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John Henry: "Pray do not ascribe that notion to me": God and Newton's
Gravity
"Pray
do not ascribe that notion to me": God and Newton's Gravity
by John Henry
© Kluwer Academic
Publishers 1994
Previously published as:
"'Pray do not
ascribe that notion to me': God and Newton's Gravity", in The
Books of Nature and Scripture: Recent Essays on Natural Philosophy,
Theology and Biblical Criticism in the Netherlands of Spinoza's Time
and the British Isles of Newton's Time, edited by James E. Force
and Richard H. Popkin (Kluwer Academic Publishers, Dordrecht, 1994),
pp. 123-47.
The precise nature of the force of gravitational attraction was always
problematic for Isaac Newton. As is well known, he was forced by the
criticism of Leibniz to acknowledge in the General Scholium to the Principia
mathematica that he did not know the cause of gravity. Making a virtue
out of a necessity, he insisted that he was not interested in feigning
explanatory hypotheses, being perfectly content to show "that gravity
does really exist and act according to the laws which we have explained".
Elsewhere, however, as is also well known, Newton did try out various
explanatory hypotheses. Essentially, Newton's speculations derived from
four earlier traditions with which he was familiar. Drawing upon the
Neoplatonic tradition of light metaphysics, he suggested that light might
combine with matter to give it various active powers; the alchemical
tradition linked ideas of light with ideas of an active spirit, present
in all things, which again might be said to give rise to various unceasing
activities of matter. This active spirit, in its turn, could be linked
to more recent ideas, developed in the new mechanical philosophy, in
which an all pervasive aether was used as a medium of transmitting impulse
from one part of the universe to another. Newton's own aether speculations
were by no means purely mechanistic, since his aether consisted of particles
held apart from one another, and from particles of other matter, by repulsive
forces operating between them, but they clearly owed something to the
mechanical as well as the alchemical traditions. The fourth tradition
was Christian theology: Gravitational attraction being held to be brought
about by God.[1]
What I want to do in this paper is look at the fourth of these explanatory
speculations. The general consensus among historians of Newton's thought
is that none of the first three proved satisfactory to Newton for long.
The conclusion, therefore, is that God was Newton's most favoured explanation
for Gravity. However, it seems to me that the precise way in which Newton
was said to have invoked God to explain gravity is based on a misreading
and a misunderstanding of one or two crucially important pronouncements
of Newton's. Let's begin, therefore, by looking at what some of the leading
Newtonian scholars have said about God and Newton's gravity.
A. Rupert Hall in his The Scientific Revolution (1954) noted
that Newton, on a superficial view of his writings, seems to believe
in gravitational attraction as an inherent property of matter which was
capable of acting at a distance, but Hall simply denies that Newton could
ever have thought this way:
That Newton seemed, by the theory of universal gravitation, to contravene
the principles of mechanism, was due to misapprehension. Though certain
phrases in the Principia might seem to indicate the contrary he did not
believe that gravity was an innate property of matter, nor that two masses
could attract each other at a distance without some relationship.
Thirty years later, when Hall rewrote this book under the title The
Revolution in Science, he found himself able to say that Newton's
comments upon gravity took him to an "impasse":
On the one hand Newton says that no aetherial means, or presumably
any kind of material mechanism occupying the celestial spaces, can exist;
on the other he says that the existence of gravitational force within
a void without "mediation" between the masses is absurd.
The way out of this impasse, Hall declares, referring for support to
Newton's friends Fatio de Duillier and David Gregory, was to invoke God
as the cause of gravitational attraction. More recently, Hall has insisted
that "Newton was... certain... that though these powers, virtues or forces
[including gravity] are invariably associated with matter, they are not
produced by matter". Newton's subsequent attempts to explain the principle
of gravity by alternative natural means are described by Hall as confusing.
He then goes on to discuss the role of God in Newton's gravitational
theory, suggesting at one point that God is the agent "continually at
work" to produce gravitational effects, and at another that the "certain
very subtle spirit penetrating dense bodies", which Newton refers to
in the General Scholium appended to the second edition of the Principia,
is to be identified with Newton's "idea of ubiquitous, active God".[2]
Alexandre Koyré, in his influential Newtonian Studies of
1965, claimed that,
It is well known that Newton did not believe gravity to be an "innate,
essential and inherent property of matter"... attraction as action at
a distance through vacuum without mediation... was an utter absurdity
that nobody could believe in...
Like Hall, KoyréÇ also talks of a misapprehension by
Newton's contemporaries of what he meant. Readers of the first edition
of the Principia "could hardly fail to misunderstand Newton's
position and to ascribe to him just those opinions which he so vehemently
rejected...", he wrote. And a bit later he said, "It may seem rather
surprising, in spite of these very decided and definite declarations
by Newton,... that his teaching could be, and was, interpreted as positing
action at a distance by an attractive force residing in bodies." Koyré,
however, insists that Newton had in fact stated quite clearly that gravity
had to be "performed by something which is not material, that is, by
God."[3]
Hall's and Koyré's belief that Newton relied more or less directly
upon God to explain the force of gravity is bound up with their belief
that he did not believe action at a distance to be possible and that
gravitational attraction could not, therefore, be a property of matter.
This same view of Newton's thinking has been most forcefully stated by
I. Bernard Cohen, in a recent article on "Newton's Third Law and Universal
Gravity". This is what Cohen writes:
From the time of his Principia until his death Newton was deeply
troubled by the concept he had introduced: a universal gravity. He had
been brought up in the "received" philosophy, sometimes known as the "mechanical
philosophy," centering around the ideas of Descartes, which held that
all explanations in natural philosophy must be couched in terms of what
Robert Boyle called "those two grand and most catholick principles of
bodies, matter and motion." At first sight it would seem that to these
Newton had added a third principle, force. Not only was this a departure
from accepted norms, it also introduced a kind of force that was astonishing
in its primary characteristics or qualities. For this force had to have
the power of extending itself over many hundreds of millions of miles
as a kind of grasping entity which could affect huge bodies. For instance,
the gravitational force could extend far beyond the reaches of the solar
system... to turn a comet around and cause it to return to the visible
regions of the neighbourhood of the sun. Newton again and again sought
for some explanation of how universal gravity might act. That is, he
attempted to reduce universal gravity to the action of something else,
a shower of aether particles, electrical effluvia, variations in an all-pervading
aether. All of these attempted "explanations" or reductions of universal
gravity to some accepted kind of mechanism failed - because none could
fulfill two major requirements: that the resultant force vary inversely
as the square of the distance and that this force act mutually on every
pair of bodies so as to attempt to bring them together.
Now, one of the crucial factors in this account of an embarrassed Newton,
is that it is beyond doubt because it is fully chronicled. As Cohen goes
on to say, "It is well known that by the time of the second edition of
the Principia, in 1713, Newton publicly acknowledged the difficulty...
in accepting the action-at-a-distance of universal gravity..." And a
little later: "Newton's aversion to accepting a force that acts at a
distance without any secondary explanatory mechanism is well documented...".
This being so, Cohen goes on to ask, "How, then, could Newton have initially
been able to consider the properties and actions of a force of "attraction",
of a type in which he could not fully believe?"[4] We
need not pursue the details of Cohen's attempt to answer this question
because it is my contention that it is based on a misunderstanding of
Newton's views on the nature of gravitational attraction.
So, according to Hall, KoyréÇ and Cohen, Isaac Newton
did not believe that gravity could be an inherent property of matter,
and he did not believe that action at a distance was possible "without
mediation". However, in spite of his own very clear statements to this
effect, Newton was completely misunderstood by most of his contemporaries.
Furthermore, the fullest modern attempt to understand Newton's meaning
on these matters, that of Ernan McMullin in his book Newton on Matter
and Activity (1978), also found it extremely difficult to understand
Newton. McMullin confessed that he had "failed to identify any single
principle, consistently pursued, as the driving force behind Newton's
search for an explanatory account of gravitational motion". McMullin's
failure can be attributed to the fact that he could not reconcile Newton's
clear and unabashed pronouncements on the reality of actions at a distance
in a number of places in his writings, with a couple of famous, and very
insistent, statements by Newton that actions at a distance are impossible.[5]
All of these writers have been very influential and their reading of
Newton on this important issue has almost become canonical. So much so,
that nobody now makes any serious attempt to resolve these difficulties.
It is simply assumed that, as McMullin implies, Newton's problems were
intractable and that he never did reach a consistent position; or that,
as Hall says, Newton merely speculated "confusingly".[6] It
is my contention, however, that this standard account is almost entirely
based on a misreading of two crucial statements where Newton is supposed
to have denied that gravity is inherent in matter, and that action at
a distance is impossible.
These crucial statements appear in two passages in Newton's letters
to Richard Bentley, written between December 1692 and February 1693 when
Bentley was preparing his Boyle Lectures for the press. In the second
of his letters to Bentley, Newton wrote:
You sometimes speak of Gravity as essential and inherent to Matter.
Pray do not ascribe that Notion to me; for the Cause of Gravity is what
I do not pretend to know, and therefore would take more Time to consider
it.[7]
This is quoted in every recension of the canonical account. With good
reason since it seems to me to be literally a sine qua non. In the following
letter Newton partially explains his meaning:
The last Clause of the second Position I like very well. It is inconceivable,
that inanimate brute Matter should, without the Mediation of something
else, which is not material, operate upon, and effect other Matter without
mutual Contact, as it must be, if Gravitation in the Sense of Epicurus,
be essential and inherent in it. And this is one Reason why I desired
you would not ascribe innate Gravity to me. That Gravity should be innate,
inherent and essential to Matter, so that one Body may act upon another
at a distance thro' a Vacuum, without the Mediation of any thing else,
by and through which their Action and Force may be conveyed from one
to another, is to me so great an Absurdity, that I believe no Man who
has in philosophical Matters a competent Faculty of thinking can ever
fall into it. Gravity must be caused by an Agent acting constantly according
to certain Laws; but whether this Agent be material or immaterial, I
have left to the Consideration of my Readers.[8]
There can be no doubt, then, about the vigour of Newton's denials.
Small wonder that Koyré, Hall, McMullin, Cohen and all those who
have followed them found it hard to reconcile the suggestion that no
man with a competent faculty of thinking could ever believe in action
at a distance with all those statements in the Queries appended to the Opticks where
Newton talks glibly of actions at a distance. Consider for example, Query
29:
Pellucid Substances act upon the Rays of Light at a distance in refracting,
reflecting, and inflecting them, and the Rays mutually agitate the Parts
of those Substances at a distance for heating them; and this Action and
Re-action at a distance very much resembles an attractive Force between
Bodies.
And, of course, Query 31:
Have not the small Particles of Bodies certain Powers, Virtues, or
Forces, by which they act at a distance, not only upon the Rays of Light
for reflecting, refracting, and inflecting them, but also upon one another
for producing a great Part of the Phaenomena of Nature? For it's well
known, that Bodies act one upon another by the Attractions of Gravity,
Magnetism and Electricity; and these Instances shew the Tenor and Course
of Nature, and make it not improbable but that there may be more attractive
Powers than these.[9]
But there is an easy way out of this dilemma. What we have to ask ourselves
is, what exactly is Newton denying so vigorously in his letters to Bentley?
Is Newton saying, for example, that gravity is not a property of matter
at all, since matter is inert and passive? In which case McMullin is
correct in supposing that Newton had set himself "the thankless task
of finding a home for forces somewhere else than in matter".[10] Is
Newton implying that, in fact, gravitational attraction should be taken
to be a Spirit - spirits after all are active principles - which is all-pervasive
but independent of matter? This is the line taken by R.S. Westfall and
Betty Jo Dobbs.[11] Or, is he perhaps
saying that gravitational attraction must be directly performed by God
- "an Agent acting constantly"?
In fact, we do not have to accept any of these interpretations. There
is another reading in which these pronouncements in the letters to Bentley
can be seen to be perfectly compatible with all his other statements
or speculations on the nature of gravity and other forces, including
those optical Queries where he calmly proposes the operation of actions
at a distance.
An obvious place to seek help in interpreting Newton's meaning is to
look to see what Richard Bentley, the recipient of the letters, made
of these particular passages. At the relevant point in his Seventh Boyle
Lecture ("A Confutation of Atheism from the Origin and Frame of the World"),
Bentley rejected the notion that Gravity was inherent in or essential
to matter, "so that several Particles placed in a Void space at any distance
whatsoever would without any external impulse spontaneously convene and
unite together." Still following Newton's lead, Bentley identifies this
rejected view as the "Epicurean Theory of Atoms descending down an infinite
space by an inherent principle of Gravitation".[12] Now
this is important because none of the commentators in the canonical tradition
have ever pointed to the puzzling nature of Newton's reference to Epicurus
in his third letter to Bentley. "It is inconceivable", Newton said, "that...
Matter should... operate upon and affect other Matter without mutual
Contact, as it must be, if Gravitation in the sense of Epicurus be essential
and inherent in it."[13]
It seems clear that the concern of both Newton and Bentley is to dissociate
Newton's concept of gravity from the ancient system of Epicurus which
was generally regarded as atheistic. Neither man wanted to provide hostages
to the ranks of atheists which they perceived to be an ever-present threat
to their society and their religion. If gravity and other principles
of activity could be said to be essential and inherent in matter, then
the universe might seem capable of running itself, without the benefit
of divine guidance. So, when Newton said "Pray do not ascribe that notion
to me", the notion he was objecting to was not that gravitational attraction
might be a property of matter, but that gravitational attraction might
be held to be an essential property of matter, in the way that extension
was held to be. Extension was generally agreed to be an essential attribute
of matter. Matter could not be conceived of without extension but it
could easily be conceived of without gravitational attraction.
But what about the other notion that Newton is supposed to have rejected
in his letter to Bentley: the notion of action at a distance? How did
Bentley treat this in his Boyle Lecture? Surely he must have rejected
it out of all countenance? Evidently not. In fact, this is what he wrote:
Now, mutual gravitation or attraction, in our present acceptation of
the words is the same thing with this, 'tis an operation, or virtue,
or influence of distant bodies upon each other through an empty interval,
without any effluvia or exhalations, or other corporeal medium to convey
and transmit it.[14]
Are we to assume that Bentley simply disagreed with Newton's objections
to action at a distance? Was Bentley sufficiently confident in his own
powers "in philosophical Matters" that he chose to disregard Newton's
strictures against this great absurdity of action at a distance? Certainly
this is the line that Alexandre KoyréÇ and, more recently,
Perry Miller have taken.[15] As we shall see later, both of these commentators
have blamed Bentley for the fact that most of Newton's contemporaries
thought, erroneously according to KoyréÇ and Miller, that
he did believe in action at a distance.
If we read on, however, it becomes possible to see that Bentley was
not ignoring Newton's advice but was putting it to good use:
This Power therefore cannot be innate and essential to Matter. And
if it be not essential; it is consequently most manifest (seeing it doth
not depend upon Motion or Rest or Figure or Position of Parts, which
are all the ways that Matter can diversify itself) that it could never
supervene to it [matter], unless impress'd and infused into it by an
immaterial and divine Power.[16]
Bentley can be seen to be providing here a very clear statement of
exactly what Newton had in mind about the nature of gravity. Gravity
is a power, or virtue which has been superadded to matter by God. Certainly
there is nothing in Newton's letters to Bentley which directly contradicts
this description, nor even so much as a hint that he dissents from it.
We have no reason to suppose (although, as we shall see later, a number
of scholars have supposed) that Bentley misunderstood Newton and misrepresented
his ideas.
It is important to be clear about what Bentley is saying. The fact
that he refers to mutual gravitation implies straight away that he takes
gravity to be acting between bodies, not for example between a body on
the one hand and the centre of rotation of a vortex, as in the Cartesian
system, on the other hand. So, gravity is a virtue, or influence of one
body on another at a distance ("distant bodies"), through absolutely
empty space - not even a tenuous effluvium is required to transmit it.
He then goes on to draw implications from this. These implications are
fully in keeping with Newton's denials about gravity in his letters to
Bentley. This mutual attraction cannot be essential to matter, like extension.
Furthermore the gravitational attractive power of any given body cannot
be shown to be an epiphenomenon of the arrangement or motions of the
particles which constitute that body. The only alternative, therefore,
is to suppose that this non-essential power is superadded to bodies by
(who else but) "an immaterial and divine power".
So, Newton could be said to fully accept what Bentley says here without
having a belief in innate gravity ascribed to him. Moreover, it is now
possible to understand the otherwise deeply puzzling claim of Newton
in his letter to Bentley that he has "left to the consideration of [his]
Readers", whether the Agent responsible for gravity is material or immaterial.
This is deeply puzzling on the standard reading because Newton says just
a few lines above this: "It is inconceivable, that inanimate brute Matter
should, without the Mediation of something else, which is not material,
operate upon, and effect other Matter without mutual Contact..." In what
sense does he leave his readers to decide whether the agent responsible
for gravity is material or immaterial, when he has already told his readers
that action at a distance is inconceivable without the mediation of something
which is not material?
To resolve this difficulty we simply have to realize that the "Agent
acting constantly according to certain laws", which is the immediate
cause of gravity and which could be either material or immaterial, is
different from the immaterial Mediator which endows matter with the non-essential
power of attracting other matter. It is inconceivable, Newton is saying,
that matter should have a power to attract other matter at a distance
unless such power is mediated or brought about by God. Certainly, Bentley
himself interpreted Newton's letter this way, as can be seen by a close
paraphrase in the seventh lecture:
'Tis utterly unconceivable, that inanimate brute Matter (without the
mediation of some Immaterial Being) should operate upon and affect other
Matter without mutual Contact...
Or, as Bentley wrote in one of his letters to Newton:
"tis unconceivable, yt inanimate brute matter should (without a divine
impression) operate upon & affect other matter without mutual contact:
as it must, if gravitation be essential and inherent in it.[17]
Note that Bentley seems to be admitting at this point in his letter
(and Newton never took him to task for this) that if gravitation is essential
to matter then brute matter must act at a distance. What he objects to,
and Newton by all accounts must be taken to agree with him, is not that
matter can act at a distance, but that it can be held to do so without
this ability having been conferred upon it by a divine mediator. The
objection is to the notion of gravity as essential to matter, not that
matter can be held to operate at a distance.
For both Newton and Bentley, God was the immaterial mediator whose
omnipotence enabled him to impose upon matter an agent of gravitational
attraction which acts constantly according to certain laws. Bentley,
in his Lecture, seems to imply that the agent must be immaterial ("without
any Effluvia or Exhalations or other corporeal Medium to convey and transmit
it"). If this was Bentley's opinion, Newton evidently disagreed with
him. Being a fully committed voluntarist in his theology, Newton would
not presume to say whether the agent which God chose to use was immaterial
or material.[18]
The clear implication of what Newton says in his correspondence with
Bentley is that gravity is perfectly acceptable as long as we recognize
that it must have been endowed upon matter at the creation, since it
is not logically entailed by the nature of matter, or to put it another
way, it isn't essential to matter. This is perfectly compatible, for
example, with his statement at the end of the Opticks:
All these things being consider'd, it seems probable to me, that God
in the Beginning form'd Matter in solid, massy, hard, impenetrable, moveable
Particles, of such Sizes and Figures, and with such other Properties
and in such Proportion to Space, as most conduced to the End for which
He form'd them... It seems to me farther, that these Particles have not
only a Vis inertiae, accompanied with such passive Laws of Motion as
naturally result from that Force, but also that they are moved by certain
active Principles, such as is that of Gravity, and that which causes
Fermentation...[19]
Furthermore, in case any body should still be in doubt about God's
ability to impose gravity upon matter, he later adds:
it may be also allow'd that God is able to create Particles of Matter
of several Sizes and Figures, and in several Proportions to Space, and
perhaps of Different Densities and Forces, and thereby to vary the Laws
of Nature, and make Worlds of several sorts in several Parts of the Universe.
At least, I see nothing of contradiction in all this.[20]
To recapitulate, it would seem that Newton believed that matter, which
is essentially passive, was endowed with various active principles by
God. One of these active principles was, or gave rise to, gravitational
attraction: "we must... universally allow that all bodies whatsoever
are endowed with a principle of mutual gravitation".[21] Gravity
could be said, therefore, to be a property inherent in matter providing
it was realized that it was a superadded property. Certainly, gravity
was not to be seen as a property which was logically entailed by the
nature of matter itself, in the way that extension was. Newton's natural
philosophy, based on induction and mathematical analysis, was able to
explain in precise detail the behaviour of bodies endowed with gravitational
attraction, and so reveal the regular laws which governed gravity. What
Newton freely admitted he could not do was define exactly what was the
secondary cause of gravitational attraction (the primary cause was, of
course, God). He could not even say whether it was material or immaterial.
Part of the difficulty here was surely semantic: if matter had a property
of attracting other matter at a distance without any material linkage
between them, might not this property still be designated "material" by
virtue of the fact that it was an epiphenomenon of matter?[22] Be that as it may, Newton certainly never insisted that
gravitational attraction must be brought about by some kind of immaterial
spirit, whether divine or otherwise.
I take issue, on this point, with those commentators who have taken
Newton's pronouncements in the letters to Bentley, together with some
of his statements elsewhere, to imply that gravitational attraction must
be brought about by the direct and constant intervention of God himself.
R. S. Westfall, for example, has said that the third letter to Bentley
makes it clear that Newton believed gravity was caused by an immaterial
aether. He then goes on: "What could an immaterial aether be? To Newton,
it was the infinite omnipotent God who by his infinity constitutes absolute
space and by his omnipotence is actively present throughout it". God,
Westfall reiterates elsewhere, was the "agent acting constantly according
to certain laws" that "makes bodies move as though they attract each
other".[23]
Betty Jo Dobbs, in a refinement of these arguments, has recently argued
that Newton's gravity derived from Neo-Stoic ideas in which the Stoic
pneuma becomes Platonized into an immaterial principle, which Newton,
in turn, equated with God:
a powerful ever-living Agent, who being in all Places, is more able
by his Will to move the bodies within his boundless uniform Sensorium,
and thereby to form and reform the Parts of the Universe, than we are
by our Will to move the Parts of our own Bodies.
"What we call gravitation", Dobbs writes, is nothing more than the
Divine Mind forming and reforming the Parts of the Universe.[24]
There are a number of difficulties with Westfall's and Dobbs's views.
In the first place their theories imply that Newton did not believe there
was a secondary cause of gravity. If this is so, why did he spend time
trying to find a satisfactory aetherist account? And why did he include "the
cause of gravity" among the Active Principles of body (along with "the
cause of Fermentation", for example)? Secondly, their immanentist account
of God's activity in the world is incompatible with the transcendental
theology which is more common in Newton's writings about God. Newton's
talk of space as the sensorium of God in which we live and move and have
our being[25], which is emphasized in
these interpretations, was always presented as an analogy and Westfall
and Dobbs are taking it too literally. Newton explicitly denied that
God was gravity:
In him are all things contained and moved; yet neither affects the
other: God suffers nothing from the motion of bodies; bodies find no
resistance from the omnipresence of God.[26]
Furthermore, Newton's God was a god of dominion: "Lord God, Pantokrator". "Deity",
Newton insists, "is the dominion of God not over his own body, as those
imagine who fancy God to be the soul of the world, but over servants".
We reverence and adore God, therefore,
on account of his dominion: for we adore him as his servants; and a
God without dominion, providence, and final causes, is nothing else but
Fate and Nature.[27]
Westfall's and Dobbs's God of Gravity would be, in Newton's terms,
merely Fate and Nature, "blind metaphysical necessity". Westfall is wrong,
I believe, to interpret Newton's talk of God's dominion as though it
can mean God's direct involvement: "Newton's god was the Pantocrator...
who holds dominion over all that is, ... not by his watchful providence
but by a similar dominion over the course of events". Newton's God works
indirectly, exerting his dominion to establish his providence, which
is brought about by his servants, the secondary causes.[28]
My disagreement with Westfall and Dobbs can be expressed theologically.
Westfall and Dobbs both seem to suggest that Gravity is brought about
by God's potentia absoluta, his absolute power. On my reading,
gravity is taken care of by God's potentia ordinata, his ordinary
power. Having superadded the power of gravitational attraction to bodies,
and established the laws of interaction, God need only use his ordinary
power to maintain all things in existence. This is perfectly compatible
with Newton's attempts to understand the cause of gravity in terms of
the alternative secondary causes of superadded active principles or an
aether.[29]
So, "the Agent acting constantly according to certain Laws", which
Newton refers to in his third letter to Bentley, is not God but the active
principle which God has added to the matter (either to all matter, or
merely to the matter of the aether, depending upon which speculation
Newton favoured at the time). The "Mediation" of "something else which
is not material" which then enables matter to "operate upon, and affect
other Matter without mutual Contact" need only take place once, presumably
at the creation.[30] God's continuous operation is no more required to account
for gravitational attraction than it is to account for the impenetrability
of matter, the immortality of the soul, or the continual truthfulness
of the logical law of excluded middle. Which is to say that gravity,
along with everything else in the world, has to be continually maintained
by God's arbitrary will. It is not a phenomenon of such a unique kind
that it requires a special effort on God's part to ensure from moment
to moment that it works according to plan. If Newton had believed that
gravity was such a special part of God's creation that it required his
particular attention, then Leibniz's suggestion that Newton's gravity
was "the effect of a miracle" would have been correct. But, of course,
Newton always vigorously denied this.[31]
The interpretation of the two crucial statements in Newton's third
and fourth letters to Bentley which is presented here does little more
than note a difference of emphasis. What Newton was objecting to was
not that gravity should be seen to be a property of matter but that it
should be seen to be essentially so. In case this seems like too nice
a distinction, it is worth pointing out the implications, and advantages,
of this reading for Newtonian exegesis.
Firstly, I think it is easier to see how important the Newtonian concept
of gravity is for Bentley's purpose in the Boyle Lectures and, for that
matter, for Newton himself who said in his very first letter to Bentley
that "When I wrote my Treatise about our System, I had an Eye upon such
Principles as might work with considering Men, for the Belief of a Deity,
and nothing can rejoice me more than to find it useful for that Purpose."[32] As Bentley pointed out "if it be made appear, that there
is really such a power of Gravity perpetually acting in the constitution
of the present System", then,
This would be a new and invincible Argument for the Being of God: being
a direct and positive proof, that an immaterial living Mind doth inform
and actuate the dead Matter, and support the Frame of the World.[33]
In other words, by demonstrating the existence of active principles
in matter, which although universal and inseparable from matter were
not essential to it, Newton's natural philosophy closed up the loophole
which atheists had supposedly discovered in the Cartesian system. The
Cartesian atheist only had to assume that the world was eternal to be
able to conclude that God was never required to set the whole system
a-rolling. This argument could work because the Cartesian system relied
only upon what were taken to be essential properties of matter (like
extension). The crucial role of gravity in the Newtonian system put a
stop to such atheist claims. Since, as Bentley said, "We have proved,
that a Power of mutual Gravitation, without contact or impulse, can in
no-wise be attributed to mere Matter" as an essential property (logically
entailed, as it were, in the very nature of matter), then it must have
been "impress'd and infused into it by an immaterial and divine Power",
even if the world has endured eternally. "As for Gravitation", Bentley
wrote, "tis impossible yt That should either be coaeternal & essential
to Matter, or ever acquired by it" unless it be endowed upon matter by
divine intervention.[34] It could not
be further from the truth, therefore, to suggest that Newton wished to
dissociate himself from the view that gravity was an inherent property
of matter. On the contrary, it was important for him to insist that it
was because the otherwise inexplicable presence of this property in matter
(since it was not a natural concomitant of matter, nor could it have
been acquired by matter in some natural way) provided incontrovertible
evidence for the existence of an omnipotent God.
An obvious advantage of the reading presented here, which has already
been pointed out, is that it does away with all the puzzlement in the
standard account caused by the fact that, in spite of Newton's "Pray,
do not ascribe that notion to me" in his letter to Bentley, elsewhere
he makes no bones whatsoever about talking of gravity as a property of
matter and about casually discussing the evident reality of action at
a distance. Small wonder that Koyré should believe that contemporaries "could
hardly fail to misunderstand Newton's position and to ascribe to him
just those opinions which he so vehemently rejected...", or that "in
spite of these very decided and definite declarations by Newton,... his
teaching could be, and was, interpreted as positing action at a distance
by an attractive force residing in the bodies". Similarly, as Rupert
Hall wrote in 1954, Newton "was widely misunderstood".[35] In
fact, Newton was not misunderstood; in ascribing to him a belief in action
at a distance by an attractive force residing in bodies his contemporaries,
like Bentley, were reading him correctly. His English contemporaries
in particular were used to the voluntaristic theological claim that God
could, by his arbitrary will, endow matter with various qualities and
powers. So, when Newton, in the final book of the Opticks, asks: "Do
not Bodies act upon Light at a distance, and by their action bend its
Rays...?" he did not need to explicitly invoke God's omnipotent will
at that point. Nevertheless, most English theologians, or other intellectuals
raised in the traditions of the English church, would have taken Newton's
voluntarism for granted. It is surely significant that the major critic
of such ideas, Leibniz, was a committed intellectualist in his theology,
and therefore opposed to Newton's voluntaristic approach.[36]
But the advantage of this reading is not merely confined to a better
understanding of Newton's letters to Bentley. It has implications for
our understanding of all of Newton's statements about gravity and action
at a distance. We have already seen how there is no contradiction between
his strictures to Bentley and his glib talk of actions at a distance
in the Queries to the Opticks. We can make a precisely similar
point about another problem for Newtonian exegetes, namely: What advantage
over his theory of gravitational attraction at a distance did Newton
see in his various aether theories, given that they were not mechanical
aethers but depended on repulsive forces, operating at a distance between
the particles of the aether? This issue has been raised particularly
by Ernan McMullin in his Newton on Matter and Activity.[37]
The point here is that the aether theories were not intended to be
a way of avoiding actions at a distance, which - contrary to the standard
account - Newton was not averse to, but merely a way of reducing the
number of occult qualities in the universe. Newton was swayed during
the periods of his aether speculations by the reductionist belief that
it is better to have one active matter, like the aether, responsible
for all physical activity and change than to have each and every parcel
of matter endowed with its own activity. The aether speculations do not,
therefore, represent attempts by Newton to be more "mechanical" in his
thinking than when he assumed the existence of "active principles" in
matter. And they are neither more nor less in keeping with his pronouncements
in the letters to Bentley. Active principles and aethers both entailed
a belief in matter having virtues or powers which could not be reduced
to the motions, positions, or arrangements of the particles of matter,
and which could operate at a distance. If there was an aether, the mutual
repelling forces between its particles were active principles which,
like gravity, or the cause of fermentation and cohesion in his non-aetherist
speculations, could not be essential to the aether particles.
It might be objected that there were a number of other places, besides
the letters to Bentley, where Newton denied the concept of attractive
force residing in bodies and the possibility of action at a distance.
But it seems to me that any pronouncements of Newton's which are read
this way have simply been (mis)interpreted in the light of the standard
misreadings of the letters to Bentley. Indeed, Koyré's essay, "Gravity
an Essential Property of Matter?", shows very clearly how Newton's most
significant pronouncements on gravitational attraction were all interpreted
by contemporaries in terms of a property of matter capable of acting
at a distance. KoyréÇ himself explains this, for him, lamentable
misunderstanding by virtue of the fact that Newton's contemporaries did
not have the benefit of his clear denials of this interpretation in the
letters to Bentley, which were not published until 1756.[38]
I. B. Cohen has pointed to a number of places in the Principia where
Newton seems to apologize for his use of the word "attraction", or for
his inability to give a mechanistic explanation of gravity. In the Introduction
to Section XI, of Book I of the Principia, for example, Newton
writes:
I shall therefore at present go on to treat of the motion of bodies
attracting each other; considering the centripetal forces as attractions;
though perhaps in a physical strictness they may more truly be called
impulses. But these Propositions are to be considered as purely mathematical;
and therefore, laying aside all physical considerations, I make use of
a familiar way of speaking, to make myself more easily understood by
the mathematical reader.[39]
Cohen sees this profession of mathematical instrumentalism, "laying
aside all physical considerations", as Newton's way of freeing himself
from constraints that mainstream natural philosophy would have laid upon
him - such as avoiding talk of actions at a distance. This, and the famous
disclaimer at the end of the General Scholium that he "feigns no hypotheses" concerning
the cause of gravity, are taken by Cohen to represent a sophisticated
methodological approach which enabled Newton to go further than any of
his contemporaries. Cohen is surely right about this. But we do not need
to suppose that Newton developed this means of presenting his ideas as
a result of his own "repugnance" to action at a distance, as Cohen, citing
the third letter to Bentley, seems to think.[40] We
have every reason to assume that Newton developed his sceptical, instrumentalist
and empiricist approach partly in accordance with the powerful contemporary
tradition of empiricism associated with the Royal Society of London,
and with a full awareness of the dominance of Cartesian ideas on the
Continent with their vigorous strictures against actions at a distance.[41] But another important element in Newton's approach was
his theological voluntarism, which required him to accept that God could,
if he so willed it, create bodies capable of acting upon one another
across distances. To deny this was to deny God's omnipotence. Cohen presents
Newton's sophisticated methodology, which is so important an element
in what he calls the "Newtonian style", in a rather negative, apologetic
light. For all its intellectual power and influence, it remains for Cohen
a clever escape: with one bound Newton was free of the constraints of
contemporary natural philosophy. This is only part of the story. Newton's
method was also a positive defence of the concept of action at a distance,
and therefore of the omnipotence of God.[42]
To conclude, it is worth emphasizing that Newton does not, either in
these passages in the Principia or anywhere else, deny the reality
of actions at a distance. Not even, as we have seen, in the letters to
Bentley. Similarly, his frequently cited comment in the "Advertisement" to
the second English edition of the Opticks (1717) says nothing
against actions at a distance. Once again, he simply says, "I do not
take Gravity for an essential Property of Bodies". The aetherist hypothesis
to which he is drawing the reader's attention nevertheless relies upon
actions at a distance.[43] Moreover, the hypothetical nature of the Optical
Queries encourages him to dismiss all methodological caution and explicitly
discuss actions at a distance, whether between all particles, or simply
between the particles of a putative aether.
It is surely significant, also, that although Samuel Clarke seems to
deny action at a distance during his controversy with Leibniz, in the
subsequent defence of this particular statement it becomes clear, as
Leibniz had seen straight away, that he was not denying it at all. In
his Fourth Reply Clarke wrote,
That one body should attract another without any intermediate means,
is indeed not a miracle but a contradiction: for 'tis supposing something
to act where it is not. But the means by which two bodies attract each
other, may be invisible and intangible, and of a different nature from
mechanism...
"What does he mean," Leibniz asked, "when he will have the sun to attract
the globe of the earth through an empty space?" The German philosopher
made a few suggestions, including God, immaterial substances, spiritual
rays, an accident without a substance, some kind of species intentionalis,
or a je ne sais quoi. Clarke opted for the latter:
That this phenomenon is not produced sans moyen, that is without
some cause capable of producing such an effect; is undoubtedly true.
Philosophers therefore may search after and discover that cause, if they
can; be it mechanical or not mechanical. But if they cannot discover
the cause; is therefore the effect itself, the phenomenon, or the matter
of fact discovered by experience,... ever the less true?
There are two things to notice about Clarke's final reply. Firstly
he subtly shifts his ground from denying gravitational attraction can
take place without an "intermediate means" to saying it cannot take place
without a cause. Secondly, he does not opt for God as the direct cause,
nor for any kind of immaterial entity.[44]
We have seen above how a close reading of Bentley's seventh and eighth
Boyle Lectures helps us to understand what Newton meant in the crucial
passages of his letters to Bentley. It has been more usual, however,
for historians to suppose that Bentley is not just a dubious guide to
Newton's meaning, but was downright wrong in his interpretation. It is
important for the case presented here, therefore, to try to dispel this
view of Bentley.
In his Newtonian Studies KoyréÇ placed much of
the blame for the subsequent misunderstanding of Newton on Bentley who,
we are told,
in spite of Newton's admonition, said in his Confutation of Atheism
that "a constant Energy [is] infused into Matter by the Author of all
things" and that "Gravity may be essential to Matter".[45]
Similarly, Perry Miller, writing in 1978, illustrated his doubts that
Bentley had the mental wherewithal to "fully get the point" in his discussions
with Newton by saying:
despite his effort to make clear his agreement with Newton, Bentley
still calls it [gravity] "a constant energy infused into matter by the
Author of all things".[46]
The first thing to say here is that Bentley's designation of gravity
as "a constant Energy infused into Matter", which appears in his eighth
and final Boyle Lecture, is perfectly in accordance with Newton's own
view, expressed in the letter to Bentley, that gravitational attraction
at a distance is only impossible, "without the Mediation of something
else, which is not material". It seems safe to assume, therefore, that
Newton, pace Koyré and Miller, would have seen nothing of contradiction
in the suggestion that gravitation is "a constant Energy infused into
Matter by the Author of all things". On the contrary, it entirely suited
his voluntarist theology.
But what of Koyré's report that Bentley also said that "Gravity
may be essential to matter"? Regrettably, this is simply a very bad case
of misreading by Koyré. Having said that "the concentric Revolutions
of the Planets about the Sun" can be explained in terms of a gravitational
attraction to the sun and a perpetual motion, tangential to the planet's
particular orbit, both of which (the power of attraction and the transverse
motion) being "impress'd at first by the Divine Arm", Bentley goes on
to insist that even if an atheist were to claim that these two phenomena
were not of divine origin, the system of the world as we know it could
not be shown to arise spontaneously from this force of attraction and
this tangential motion. This is what he actually wrote:
But now admitting that Gravity may be essential to Matter; and that
a transverse Impulse might be acquired too by Natural Causes, yet to
make all the Planets move about the Sun in circular Orbs; there must
be given to each a determinate Impulse... For had the Velocities of the
several Planets been greater or less than they are now, at the same distances
from the Sun; or had their Distances from the Sun, or the quantity of
the Sun's Matter and consequently his Attractive Power been greater or
less than they are now, with the same Velocities: they would not have
revolved in concentric Circles as they do, but have moved in Hyperbola's
or Parabola's or in Ellipses very Eccentric.[47]
Bentley's argument against atheists is in two parts and he introduces
the second part by means of a counterfactual. The first part of the argument
states that gravitational attraction cannot have become a property of
matter unless it had been put there by God. The second part of the argument,
which relies upon the supposedly clear signs of intelligent design in
the universe, suggests that even if gravity was part of the essence of
matter the atheist can go no further without invoking a cosmic intelligence.
A. R. Hall has also taken Bentley to task for going beyond what Newton
intended. Having accepted Newton's insistence that gravity is not essential
and inherent to matter, Hall wrote, Bentley unwarrantably jumped to the
conclusion that gravity must, therefore, have been impressed and infused
into it by God. According to Hall, "This blurs Newton's clear contention" that
God, acting continually, is directly responsible for gravitational effects.[48] I have already argued above that this is based on a misunderstanding
of Newton's theology. Once again. I suggest, Bentley's reading of Newton
can be taken to approach very close to what Newton himself intended.
It is perhaps worth mentioning also, that there is a total lack of any
circumstantial evidence that Newton was in any way upset by Bentley's
use of his ideas. As is well known, Newton allowed Bentley to supervise
the preparation of the second edition of the Principia for the press,
an unlikely position of trust for one who had supposedly so badly misunderstood
the philosophical and theological import of Newton's work.
Besides, there is some evidence to suggest that the huge importance
bestowed by historians upon the crucial statements of Newton's in his
correspondence with Bentley does not reflect the attitude of the correspondents
themselves. The original mistake which Newton picked upon: "You sometimes
speak of Gravity as essential and inherent to Matter", was, according
to Bentley, only loose talk: "If I used yt word, it was only for Brevity's
sake". Perry Miller dismisses this excuse, but we have no real reason
for supposing it wasn't true.[49] Bentley did not, after all, let slip in one
of his published lectures that "Gravity may be essential to Matter" -
except (as we have seen) when he was putting the atheists' case for them.
If Bentley was a bit slapdash in his choice of word, he was in good
company. Roger Cotes, who edited the second edition of the Principia and
who furnished it with an editorial Preface, also slipped into referring
to gravity as essential to matter. He dropped it at the advice of Samuel
Clarke but if we go by the evidence of Cotes's letter, which is all we
can go by (since Clarke's advice seems to have been passed on orally
by a Dr Cannon), it wasn't seen as a horrendous faux pas:
I return my thanks for Your corrections of the Preface, & particularly
for Your advice in relation to that place where I seem'd to assert Gravity
to be Essential to Bodies. I am fully of Your mind that it would have
furnish'd matter for Cavilling and therefore I struck it out immediately
upon Dr Cannon mentioning Your Objection to me...[50]
Cotes's slip becomes for Koyré "an obvious error for which he
was taken to task by Clarke". It is perhaps symptomatic of Koyré's
overemphasis of the importance of this issue that he failed to notice
that this criticism was passed on orally by an intermediary. Koyré tells
us that, "Clarke's letter has not been preserved and one can only infer
its contents from Cotes's answer." It would seem that in Koyré's
eyes the error that Cotes made was so bad that it was inconceivable that
it could have been dealt with so casually.[51]
It is difficult to know what kind of further "Cavilling" Cotes and
Clarke thought the word "essential" would have inspired, given that what
they did allow to stand in the new "Preface" made a bold plea for asserting
gravity to be the metaphysical equivalent of extension, mobility and
impenetrability, the three mainstays of the mechanical philosophy. Taking
an empiricist line, Cotes insists that the extension, mobility and impenetrability
of bodies are known only by observations and experiments. But the same
method teaches us that all bodies are heavy. It will not do, Cotes says,
to argue that we have not yet observed the gravity of the fixed stars
because we have not yet observed their extension, mobility or impenetrability. "In
short", he concludes,
either gravity must have a place among the primary qualities of all
bodies, or extension, mobility, and impenetrability must not. And if
the nature of things is not rightly explained by the gravity of bodies,
it will not be rightly explained by their extension, mobility, and impenetrability.[52]
One thing is certain, Cotes was not riding a hobby-horse of his own
making here. He was drawing directly upon his understanding of Newton's
opinions, and in particular upon what he took to be the intention of
Newton's Third Rule of Reasoning. In his own explanation of the significance
of this rule Newton wrote:
if it universally appears, by experiments and astronomical observations,
that all bodies about the earth gravitate towards the earth, and that
in proportion to the quantity of matter which they severally contain;...
and all the planets [gravitate] one towards another; and the comets in
like manner towards the sun; we must, in consequence of this rule, universally
allow that all bodies whatsoever are endowed with a principle of mutual
gravitation. For the argument from the appearances concludes with more
force for the universal gravitation of all bodies than for their impenetrability;
of which, among those in the celestial regions, we have no experiments,
nor any manner of observation.[53]
Newton clearly wishes to suggest that gravity has as much claim to
being considered a primary, or universal, property of body as those other
primary qualities which are emphasized in the mechanical philosophy.
This is not to say, however, as Newton immediately adds, that gravity
is an essential property of body, any more than impenetrability or motion
is.[54] It seems clear, therefore, that Newton and Cotes, were
clearly concerned to argue that gravity was a property of bodies on a
par with extension, mobility, and impenetrability. At the same time,
however, it was important to maintain the theological significance of
this by insisting that gravity was not an essential, logical concomitant
of the very nature of body, but a property superadded by God.
I believe it is safe to say that all of Newton's pronouncements upon
gravitational attraction are consistent with the view that he believed
gravity to be a superadded inherent property of body which was capable
of acting at a distance. His cautious, sometimes tentative, ways of expressing
this view were only partly defensive. Certainly he wished, even more
than Cotes, to avoid "cavilling" from Cartesian mechanical philosophers,
or from the "mathematical readers" he spoke to in the introduction to
Section XI of Book I of the Principia. But he also wished to present
his philosophy in accordance with the sceptical and empiricist principles
laid down by the Royal Society, which he, like the leading Fellows of
the Society who struggled to establish it, believed to be the surest
means of establishing the true philosophy.[55] Moreover, this same way of presenting gravitational
attraction, as a casually inexplicable matter of fact, made evident by
phenomena, dovetailed perfectly with his voluntarist theology. Mysterious
though it is, God could make matter act at a distance - to deny this
was to deny God's omnipotence.
It may be countered to the reading of Newton offered here that it cannot
be correct if it disagrees so widely with the interpretations of the
foremost Newtonian scholars. This may well be true and, ultimately, I
defer to the judgement of others. But, in the meantime, it may be relevant,
and I hope not too impertinent, to offer some reflections on why these
scholars have, according to my account, consistently misread Newton's
views. I believe that the misreadings I have pointed to stem, initially,
from the preconceptions of the scholars involved. I think it is surely
significant, for example, that the leading proponents of the standard
account, Koyré, Cohen and Hall, are the most vigorous in rejecting
any suggestions that Newton was influenced by alchemy or other occult
traditions. A. Rupert Hall, for example, has recently expressed his fear
that scholarly interest in Newton's alchemy will "cloud the clarity of
reason and intellectual integrity" in the great man's life's work. "I
would have regarded Newton as a founder of reason," he wrote, "so, I
think, he wished to be regarded... not as flotsam on the weltering sea
of the human unconscious."[56] Given
this attitude, I think it is unlikely that Hall and his like-minded colleagues
could accept the passage from Bentley's lecture, which I quoted earlier,
as a valid illustration of what Newton had in mind about the nature of
Gravity:
Now mutual Gravitation or Attraction (in our present acceptation of
the Words) is the same thing with This; 'tis an operation or vertue or
influence of distant Bodies upon each other through an empty Interval,
without any Effluvia or Exhalations or other corporeal Medium to convey
and transmit it.[57]
This is much too obviously an occult view of gravity. If Newton is
to be preserved from the taint of occultism, then this cannot be his
view but must be the mistaken view of Bentley. Fortunately, this is easy
to establish, since we have clear and unequivocal evidence in the letters
to Bentley that Newton rejected these very ideas - or so the old familiar
story goes. But Newton's own writings do not allow much freedom of interpretation.
Accordingly, these scholars have opted for what seemed to them the only
other alternative, as Cotes foretold in his Preface to the 1713 edition
of the Principia: "either they will deny gravity to be in bodies,
which cannot be said, or else, they will therefore call it preternatural",
which is to say, directly caused by God.[58]
The mechanical philosophy is still regarded fondly by thinkers like
Koyré, Hall, Cohen and many others, as the foundation upon which
all subsequent scientific thinking was erected. We got where we are today,
thanks to the rejection of occult ways of thinking and the development
of the supremely rational ways of thinking of mechanical philosophers
like Galileo, Descartes, and above all Isaac Newton. So, even though
Koyré, Hall and Cohen accept that Newton did indeed introduce
attractive forces seemingly capable of acting over distances of empty
space, they insist on giving a non-occultist account of how he developed
these notions. All three of them, therefore, emphasize the importance
of Newton's methodological pronouncements in his three rules of philosophizing,
in his insistence that it is enough that he has shown that gravity does
really exist and that it acts according to the laws he has discovered,
and in his development of an elaborate and unique "Newtonian style".
All this is excellent and important work but I think there can be no
doubt that it is a one-sided view of Newton, failing to see that the
first modern scientist was also the last of the magi.[59]
This view is also bound up with the still dominant, late-nineteenth-century
trend in physics to denounce and reject all suggestions of action at
a distance. From Faraday, Thomson, and Maxwell onwards, actions at a
distance have been excluded from legitimate scientific theorizing. There
was no such all-pervasive prejudice in the seventeenth and eighteenth
centuries as a number of historical studies have clearly shown.[60] Indeed,
F. H. van Lunteren has recently pointed to the use of Newton's letters
to Bentley by the nineteenth-century opponents of distance-forces:
the phrase in the third letter to Bentley expressing the absurdity
of bodies acting upon another at a distance without the mediation of
anything else must have been Newton's most frequently quoted statement
in the second half of the nineteenth century.[61]
Newton's words to Bentley came to be seen, therefore, as authoritative
pronouncements on the impossibility of actions at a distance, and, of
course, clear evidence that the great Newton never believed in them.
Having been invested with this kind of authority it is hardly surprising
that the original meaning of his words became hard to see. It is the
authoritativeness of this reading, perhaps, which prevented R. S. Westfall
and Betty Jo Dobbs, two scholars who have never ignored the occult side
of Newton, from seeing Newton's comments to Bentley as a tacit acceptance
of the possibility of action at a distance.
The history we write, because it depends upon our perceptions as much
as the historical evidence, is bound to tell us something not only about
our past but also about ourselves. It is this last aspect of history-writing
which enables subsequent generations of historians (with a different
set of preoccupations) to recognize what reflects the past and what reflects
the recently present in the histories of the previous generation. Each
generation, therefore, in spite of the handicap of its own preconceptions,
can build upon the previous work to refine its reading of the past, sifting
out the more "presentist" elements and approaching ever closer to the
way things were. "So we beat on, boats against the current, borne back
ceaselessly into the past."[62]
Notes for "Pray Do Not Ascribe that Notion to Me"
Earlier versions of this paper were read to the Open University History
of Philosophy Research Group Seminar, at Birkbeck College, London (May,
1990); and at a conference on "Ciència i Religió: Perspectives
Històriques i Filosòfiques", held in the Department of
Philosophy of the Universitat Autonoma de Barcelona, in Catalonia (March
1992). I am grateful to Professor Tom Sorrell of the Open University,
and Professor Antoni Malet of the Universitat Autonoma de Barcelona for
inviting me to air my views, and for their generous hospitality during
my visits. I owe many thanks also to the audiences on both occasions
for their helpful and encouraging comments.
[1] The role of light metaphysics in
Newton's thinking has not received separate treatment but see Ernan McMullin, Newton
on Matter and Activity (Notre Dame and London, 1978), pp. 84-96.
The role of light is also alluded to in some of the discussions of Newton's
alchemy, particularly when discussing his alchemical treatise, "On the
Vegetation of Metals", and his "Hypothesis explaining the Properties
of Light" of 1675. See, for examples, P. M. Rattansi, "Newton's Alchemical
Studies", and R. S. Westfall, "Newton and the Hermetic Tradition", both
in A. G. Debus (ed.), Science, Medicine and Society in the Renaissance (New
York, 1972), pp. 167-82 and 183-98; and J. E. McGuire, "Transmutation
and Immutability: Newton's Doctrine of Physical Qualities", Ambix,
14 (1967), 69-95. On Newton's aether speculations see Henry E. Guerlac, "Newton's
Optical Aether", Notes and Records of the Royal Society of London,
22 (1967), 45-57; P. M. Harman, "Ether and Imponderables", in G. N. Cantor
and M. J. S. Hodge (eds), Conceptions of Ether (Cambridge, 1981),
pp. 61-83; and R. W. Home, "Newton on Electricity and the Aether", in
Zev Bechler (ed.), Contemporary Newtonian Research (Dordrecht,
1982), pp. 191-213. Newton's pronouncements on gravity as an effect brought
about by God are discussed in R. S. Westfall, Never at Rest: A Biography
of Isaac Newton (Cambridge, 1980), pp. 505-11. Westfall's biography
should be consulted for excellent discussions of all the foregoing issues
as well (the index is excellent). Isaac Newton, Mathematical Principles
of Natural Philosophy, translated by Andrew Motte, revised by Florian
Cajori (Berkeley, 1946), p. 547.
[2] A. Rupert Hall, The Scientific
Revolution (London, 1962), p. 273; idem, The Revolution in Science,
1500-1750 (London, 1983), p. 323; idem, Henry More: Magic, Religion
and Experiment (Oxford, 1990), p. 231, 232, 238, 240. Although
the first two of these books were intended for undergraduate audiences,
I have included them in my survey because that will have gained them
a certain amount of influence in the field.
[3] Alexandre Koyré, "Gravity
an Essential Property of Matter?", in idem, Newtonian Studies (London,
1965), pp. 149-63, see p. 149, 152, 149.
[4] I. B. Cohen, "Newton's Third Law
and Universal Gravitation", Journal of the History of Ideas, 48
(1987), 571-93, pp.587-88, 588-89. This article also appears in P.B.
Scheurer and G. Debrock (eds), Newton's Scientific and Philosophical
Legacy (Dordrecht, 1988), pp. 25-53.
[5] Ernan McMullin, Newton on Matter
and Activity (see note 1), p. 104.
[6] McMullin, Newton on Matter and
Activity (see note 1), pp. 105-6; Hall, Henry More (see
note 2), p. 232.
[7] Isaac Newton, Four Letters from
Sir Isaac Newton to Doctor Bentley containing some Arguments in Proof
of a Deity (London, 1756), Letter II, p. 20. This letter is dated
January 17 1692/3. The letters are conveniently reprinted in I. B Cohen
(ed.), Isaac Newton's Papers & Letters on Natural Philosophy,
2nd edition (Cambridge, Mass., and London, 1978), pp. 279-312. See,
p. 298. Henceforward I will refer to this edition, as Papers & Letters,
and give page numbers of the original edition in brackets.
[8] Papers & Letters, pp.
302-3 (25-6). This letter is dated February 25, 1692/3.
[9] Isaac Newton, Opticks, or A Treatise
of the Reflections, Refractions, Inflections & Colours of Light,
based on the 4th edition London, 1730 (New York, 1979), pp. 370-1,
375-6.
[10] McMullin, Newton on Matter and
Activity (see note 1), p. 53.
[11] R. S. Westfall, "The Rise of
science and the Decline of Orthodox Christianity: A Study of Kepler,
Descartes, and Newton", in D. C. Lindberg and R. L. Numbers (eds), God
and Nature: Historical Essays on the Encounter between Christianity and
Science (Berkeley, 1986), pp. 218-37, especially p. 233; B. J. T.
Dobbs, "Newton's Alchemy and his 'Active Principle' of Gravitation",
in P. B. Scheurer and G. Debrock (eds), Newton's Scientific and Philosophical
Legacy (Dordrecht, 1988), pp. 55-80, p. 74. These are discussed more
fully below.
[12] Papers & Letters,
p. 339 (27).
[13] Richard Bentley, A Confutation
of Atheism from the Origin and Frame of the World, Part II (London,
1693), pp. 331-2 (19-20). This is conveniently reprinted in Papers & Letters and
I will refer to that edition henceforth, giving page numbers of the
original edition in brackets.
[14] Papers & Letters,
p. 302 (25).
[15] Koyré, "Gravity an Essential
Property of Matter?" (see note 3), p. 149. Perry Miller, "Bentley and
Newton", in Papers & Letters, pp. 271-78.
[16] Papers & Letters,
p. 341 (29). See also, pp. 332-3 (20-1), and p. 363 (p. 11 in Part III,
the Eighth Lecture).
[17] Papers & Letters,
p. 340 (28). Bentley, Letter to Newton, 18 February, 1692/3, see H.W.
Turnbull et al. (eds), The Correspondence of Isaac Newton, 7 vols.
(Cambridge, 1959-71), iii, pp. 246-253, p. 249.
[18] For discussions of Newton's voluntarism
see Francis Oakley, "Christian Theology and the Newtonian Science: The
Rise of the Concept of Laws of Nature", Church History, 30 (1961),
433-57; and J. E. McGuire, "Force, Active Principles and Newton's Invisible
Realm", Ambix, 15 (1968), 154-208.
[19] Newton, Opticks (see note
9), pp. 400-01.
[20] Newton, Opticks (see note
9), pp. 404-5.
[21] Newton, Principia (see
note 1), p. 399.
[22] This is a difficult point to
get across. Consider the phenomena of shadows. Would it not seem misleading
to describe shadows as immaterial entities? The unenlightened might jump
to the conclusion that shadows must, therefore, be spiritual beings.
To avoid this, we might prefer to consider them to be material phenomena,
even though they are not composed of matter, because they are produced
by the behaviour of matter and cannot exist without material objects
to bring them into existence. Perhaps there should be a third category
for referring to such epiphenomena of matter, but in the meantime, whether
shadows are material or immaterial must be left to the consideration
of individuals. Another point to bear in mind when dealing with historical
concepts of matter and spirit is that the distinction between material
and immaterial in seventeenth-century thought was by no means always
so clear cut as it was in fully committed philosophical dualists, such
as Descartes or Henry More. The status of light, for example, on a spectrum
from material to immaterial never achieved a consensus, and J. E. McGuire
in his detailed studies of Newton's concept of force certainly concluded
that Newtonian forces and other active principles were part of an "invisible
realm" which could not definitively be said to be either corporeal or
incorporeal, but was rather something in between. See McGuire, "Force,
Active Principles and Newton's Invisible Realm" (see note 18).
[23] R. S. Westfall, Force in Newton's
Physics: The Science of Dynamics in the Seventeenth Century (London
and New York, 1971), p. 396. Westfall, "The Rise of science and the
Decline of Orthodox Christianity: A Study of Kepler, Descartes, and
Newton" (see note 11), p. 233.
[24] Newton, Opticks (see note
9), p. 403. B. J. T. Dobbs, "Newton's Alchemy and his 'Active Principle'
of Gravitation" (see note 11), p. 74; see also idem, "Stoic and Epicurean
Doctrines in Newton's System of the World", in Margaret J. Osler (ed.), Atoms,
Pneuma, and Tranquility: Epicurean and Stoic Themes in European Thought (Cambridge,
1991), pp. 221-38, especially pp. 232-38.
[25] For a full discussion of Newton's
speculations about space as the "sensorium" of God see Edward Grant, Much
ado about Nothing: Theories of Space and Vacuum from the Middle Ages
to the Scientific Revolution (Cambridge, 1981), 247-54; B.P. Copenhaver, "Jewish
Theologies of Space in the Scientific Revolution: Henry More, Joseph
Raphson, Isaac Newton and their Predecessors", Annals of Science,
37 (1980), 489-548.
[26] Newton, Principia (see
note 1), p. 545.
[27] Newton, Principia (see
note 1), p. 544, 546.
[28] Newton, Principia (see
note 1), p. 546. Westfall, "The Rise of science and the Decline of Orthodox
Christianity: A Study of Kepler, Descartes, and Newton" (see note 11),
p. 233. McMullin also believes that Newton held immanentist views of
God's activity in the world, Newton on Matter and Activity (see
note 1), p. 55. For an excellent discussion of how Newton tries to arrive
at putative secondary causes rather than rely on God's direct intervention
see David Kubrin, "Newton and the Cyclical Cosmos: Providence and the
Mechanical Philosophy", Journal of the History of Ideas, 28 (1967),
325-46. For further discussion of Newton's transcendentalist theology
see R. H. Popkin, "Newton's Biblical theology and His Theological Physics",
in Scheurer and Debrock (eds), Newton's Scientific and Philosophical
Legacy (see note 11), pp. 81-97; and James E. Force, "Newton's God
of Dominion: The Unity of Newton's Theological, Scientific, and Political
Thought", in J. E. Force and R. H. Popkin, Essays on the Context,
Nature, and Influence of Isaac Newton's Theology (Dordrecht, 1990),
pp.75-102, especially pp.85-8.
[29] On the distinction between potentia
absoluta and potentia ordinata see Francis Oakley, Omnipotence,
Covenant and Order: An Excursion in the History of Ideas from Abelard
to Leibniz (Ithaca and London, 1984); J. E. McGuire, "Boyle's Conception
of Nature", Journal of the History of Ideas, 33 (1972), 523-42;
and idem, "Force, Active Principles and Newton's Invisible Realm" (see
note 18).
[30] Mediation does not necessarily
imply an ongoing continuous process. According to the Oxford English
Dictionary "to mediate" can mean: "To be the intermediary or medium
concerned in bringing about [a result] or conveying [a gift etc.]...".
[31] For discussion of Leibniz's accusation
and Newton's response see Koyré, "Attraction an Occult Quality?",
idem, Newtonian Studies (see note 3), pp. 139-48.
[32] Papers & Letters,
p. 280 (1).
[33] Papers & Letters,
p. 342 (30).
[34] Papers & Letters,
p. 341 (29). Bentley, letter to Newton, 18 February 1692/3, in H. W.
Turnbull et al. (eds), Correspondence of Isaac Newton (see
note 17), p. 249.
[35] Koyré, "Gravity an Essential
Property of Matter?" (see note 3), p. 149, 152. Hall, The Scientific
Revolution (see note 2), p. 275.
[36] Newton, Opticks (see note
9), p. 339. In saying that English contemporaries would have taken Newton's
voluntarism for granted I do not mean to imply that they all would have
accepted it, simply that they would have recognized it for what it was.
There were, of course, English thinkers who subscribed to intellectualist
forms of theology. They would, presumably, have sympathized more with
the thinking of Leibniz. On Leibniz's intellectualist theology see A.
O. Lovejoy, The Great Chain of Being: A Study of the History of an
Idea (Cambridge, Mass., 1936), pp. 144-51; Oakley, Omnipotence,
Covenant, and Order (see note ); H. G. Alexander (ed.), The Leibniz-Clarke
Correspondence (Manchester, 1956); and Steven Shapin, "Of Gods and
Kings: Natural Philosophy and Politics in the Leibniz-Clarke Disputes", Isis,
72 (1981), 187-215.
[37] McMullin, Newton on Matter
and Activity (see note 1), pp. 95-101.
[38] Koyré, "Gravity an Essential
Property of Matter?" (see note 3), p. 149.
[39] Newton, Principia mathematica (see
note 1), Bk I, Section XI, p. 164.
[40] Cohen, "Newton's Third Law" (see
note 4), p. 592, and footnote 47 on the same page.
[41] For further discussion of this
point see Peter Dear, "Totius in verba: Rhetoric and Authority in the
Early Royal Society", Isis, 76 (1985), 145-61; and John Henry, "Occult
Qualities and the Experimental Philosophy: Active Principles in pre-Newtonian
Matter Theory", History of Science, 24 (1986), 335-81, especially
pp. 358-68.
[42] On Cohen's "Newtonian style" see
I. B. Cohen, "The Principia, Universal Gravitation, and the 'Newtonian
Style', in relation to the Newtonian Revolution in Science: Notes on
the Occasion of the 250th Anniversary of Newton's Death", in Bechler
(ed.), Contemporary Newtonian Research (see note 1), pp. 21-108;
and idem, The Newtonian Revolution: With Illustrations of the Transformation
of Scientific Ideas (Cambridge, 1980), and "Newton's Third Law and
Universal Gravitation" (see note 4). It was not, incidentally, merely
fortuitous that the Royal Society's carefully forged methodology should
prove amenable to Newton's voluntarism. the leading members of the Society
who were responsible for establishing its methods were all theological
voluntarists themselves, and they, no less than Newton, were always conscious
of the theological import of their work. For a fuller discussion see
Henry, "Occult Qualities and the Experimental Philosophy" (see note 41),
especially pp. 352-58; and idem, "The Scientific Revolution in England",
in R. Porter and M. Teich (eds), The Scientific Revolution in National
Context (Cambridge, 1992).
[43] Newton, Opticks (see note
9), p. cxxiii.
[44] Alexander (ed.), Leibniz-Clarke
Correspondence (see note 36), Clarke's Fourth Reply, para. 45,
p. 53, Leibniz's Fifth Paper, paras. 118-19, p. 94, Clarke's Fifth
Reply, para. 118-23, p. 118.
[45] Koyré, "Gravity an Essential
Property of Matter?" (see note 3), p. 149.
[46] Miller, "Bentley and Newton" (see
note 15), p. 274, 277.
[47] Papers & Letters,
pp. 363-4 (11-12, in Part III, the Eighth Lecture).
[48] Hall, Henry More (see
note 2), p. 238.
[49] Bentley, Letter to Newton, 18
February, 1693, in H.W. Turnbull et al. (eds), The Correspondence
of Isaac Newton (see note 18) iii, p. 249. Miller, "Bentley and Newton" (see
note 15), p. 275.
[50] Cotes's letter to Bentley quoted
from Koyré, "Attraction, Newton and Cotes", in Newtonian Studies (see
note 3), pp. 273-82, p. 281.
[51] Koyré, "Attraction, Newton
and Cotes", in Newtonian Studies (see note 3), pp. 273-82, p.
281.
[52] Cotes, Preface to Newton, Principia
mathematica (see note 1), p. xxvi. See also Cotes's letter to Bentley,
quoted in Koyré, "Attraction, Newton and Cotes", in Newtonian
Studies (see note 3), pp. 281-2.
[53] Newton, Principia mathematica (see
note 1), pp. 399-400. For a fuller discussion see J. E. McGuire, "Atoms
and the 'Analogy of Nature': Newton's Third Rule of Philosophizing", Studies
in the History and Philosophy of Science, 1 (1970), 3-57.
[54] Newton, Principia mathematica (see
note 1), p. 400. This line and what follows, the somewhat laconic closing
words of Newton's comments on Rule III, have posed severe problems for
Newtonian exegetes: "Not that I affirm gravity to be essential to bodies:
by their vis insita I mean nothing but their inertia. This is
immutable. Their gravity is diminished as they recede from the earth" (p.
400). McMullin (see note 1), p. 67, calls this "a perturbed and confusing
disclaimer". For a fuller discussion of the difficulties of interpreting
this passage see McMullin, pp. 61-71. In spite of McMullin's and others'
efforts the passage remains inscrutable. Fortunately the argument presented
here does not depend upon the meaning of this passage.
[55] See references in note 41 above.
The best illustration of how the Royal Society's method was seen by its
adherents as the securest means of arriving at truth is Steven Shapin
and Simon Schaffer, Leviathan and the Air-Pump: Hobbes, Boyle and
the Experimental Life (Princeton, 1985); but see also Henry, "The
Scientific Revolution in England" (see note 42).
[56] A. Rupert Hall, in a letter to
R. S. Westfall, quoted with permission in Westfall, "Newton and Alchemy",
in Brian Vickers (ed.), Occult and Scientific Mentalities in the Renaissance (Cambridge,
1984), pp.315-335, p. 316.
[57] Papers & Letters,
p. 341 (29).
[58] Newton, Principia (see
note 1), p. xxvii.
[59] On the "Newtonian style" see
note 42 above. The reference to Newton as the last of the magi is intended,
of course, to endorse John Maynard Keynes's "Newton, the Man", in The
Royal Society, Newton Tercentenary Celebrations (Cambridge, 1947),
pp. 27-34.
[60] For example, Arnold Thackray, Atoms
and Powers: An Essay on Newtonian Matter-Theory and the Development
of Chemistry (Cambridge, Mass., 1970); Robert E. Schofield, Mechanism
and Materialism: British Natural Philosophy in an Age of Reason (Princeton,
1970); Peter M. Heimann and J. E. McGuire, "Newtonian Forces and Lockean
Powers: Concepts of Matter in Eighteenth-Century Thought", Historical
Studies in the Physical Sciences, 3 (1971), 233-306. For a recent
essay which makes the same point see Curtis Wilson, "Euler on action-at-a-distance
and Fundamental Equations in Continuum Mechanics", in P. M. Harman
and A. E. Shapiro (eds), The Investigation of Difficult Things:
Essays on Newton and the History of the Exact Sciences (Cambridge,
1992), pp. 399-420.
[61] F. H. van Lunteren, "Gravitation
and Nineteenth-Century Physical Worldviews", in P. B. Scheurer and G.
Debrock (eds), Newton's Scientific and Philosophical Legacy (see
note 4), pp. 161-73, p. 166; see also note 38, p. 171, where he provides
a sample of references.
[62] These are, in case anyone does
not recognize them, the closing words of F. Scott Fitzgerald's, The
Great Gatsby (1926).
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