HUME AND REID ON NEWTONIANISM,
NATURALISM AND LIBERTY
CHRIS LINDSAY
Introductory comments
There has been a recent flurry of work comparing and contrasting the
respective methodologies of David Hume and his contemporary and
fellow Scot Thomas Reid. In his 2007 paper, “The Naturalisms of Hume
and Reid”, Louis Loeb notes that “common sense in Reid and natural
belief in Hume seem very much of a piece”.1 By drawing out the
similarities in their naturalist commitments, he argues that there is little
distance between them with respect to many of their central theses; that
Reid was one of Hume’s most notable early critics is explained by the fact
that Reid misread the Treatise. In contrast to such an approach, Penelope
Maddy argues in her 2011 paper “Naturalism and Common Sense” that
Reid’s methodology is more in keeping with contemporary naturalistic
thought than that of Hume, which is fundamentally crippled by what she
sees as a foundationalist commitment to the priority of the science of
man.2
Both writers, of course, are explicit in expressing their commitments to
a broadly Newtonian methodology. Despite the advocacy of such an
empirical approach, and despite the similarities noted by Loeb, we
nevertheless find some striking departures. One issue with respect to
which they clearly and unambiguously diverge is that of human liberty.
Where Reid is a libertarian, Hume offers several arguments that carry
1
Louis Loeb, “The naturalisms of Hume and Reid”, Proceedings and Addresses of
the APA, 81:2 (2007), pp, 65-92.
2
Penelope Maddy, “Naturalism and common sense”, Analytic Philosophy, 52:1
(2011), pp. 2-34.
2
metaphysical implications holding in favour of a compatibilist account of
liberty and necessity and against such contra-causal libertarian accounts.3
In this paper I want to unpack the methodological commitments
underlying the two different accounts of liberty. How is it that two avowed
Newtonians end up diametrically opposed to one another with respect to
such a fundamental aspect of human mentality? It is striking that, even if
one reads Hume’s account, contra the orthodox view, as consistent with
some commitment to the existence of thick connexions, the metaphysical
commitments of Hume and Reid are still poles apart. I argue that, in their
discussions of liberty, both Hume and Reid ultimately rely on claims not
grounded in naturalism or Newtonian principles. Hume is not entitled, on
purely Newtonian grounds, to reject outright the liberty of indifference, or
the existence of “a just notion of force or power”. Hume’s arguments do
not just turn upon his prior account of causation: they also rely upon some
broad empirical generalisations about human behaviour, an account of the
nature of experience and assumptions about the possible sources of the
concept of power. Each of these is problematic and subject to objection
from the libertarian on naturalist grounds. Conversely, Reid’s
libertarianism outstrips his Newtonian commitments, leading him to make
metaphysically robust claims about the existence of agent-causal powers.
Finally, I mention some brief considerations to the effect that, as far as
naturalistic commitments are concerned, the Humean compatabilist
nevertheless occupies a less problematic position than the Reidian
libertarian. I argue that such considerations cannot save Hume’s stated
position but do serve to rehabilitate some of the central theses found in his
discussion of these issues.
Newtonianism in the Scottish Enlightenment
The desire to provide an account of the mind that paralleled Newton’s
account of the physical world is, of course, a familiar theme in
philosophical writings from the 18th Century. Central to this aim was the
application of Newton’s regulae philosophandi:
Rule I: We are to admit no more causes of natural things than such as
are both true and sufficient to explain their appearances.
3
It is worth noting that James Harris has offered an interpretation of Hume that
disputes this. See: James A. Harris, Of Liberty and Necessity: The Free Will
Debate in Eighteenth-Century British Philosophy (Oxford: Oxford University
Press, 2005), and Peter Millican “Hume's Determinism”, Canadian Journal of
Philosophy, 40:4 (2010), for a response.
Rule II: Therefore to the same natural effects we must, as far as
possible, assign the same causes.
Rule III: The qualities of bodies, which admit neither intensification
nor remission of degrees, and which are found to belong to all bodies
within the reach of our experiments, are to be esteemed the universal
qualities of all bodies whatsoever.
Rule IV: In experimental philosophy we are to look upon propositions
inferred by general induction from phenomena as accurately or very
nearly true, notwithstanding any contrary hypotheses that may be
imagined, till such time as other phenomena occur, by which they may
either be made more accurate, or liable to exceptions.4
The emphasis on regularities as a basis for the postulation of general
laws and as a grounding for causal claims, as well as the rejection of
metaphysical hypotheses, are, with some qualifications, to be found in the
key works of both Hume and Reid.
Hume’s commitment to the Newtonian method is clear from the outset
of the Treatise.5 When setting out the method for his science of man, he
writes:
And as the science of man is the only solid foundation for the other
sciences, so the only solid foundation we can give to this science itself must be
laid on experience and observation. ...
For to me it seems evident, that the essence of the mind being equally
unknown to us with that of external bodies, it must be equally impossible to
form any notion of its powers and qualities otherwise than from careful and
exact experiments, and the observation of those particular effects, which result
from its different circumstances and situations. And tho’ we must endeavour to
render all our principles as universal as possible, by tracing up our experiments
to the utmost, and explaining all effects from the simplest and fewest causes,
’tis still certain we cannot go beyond experience; and any hypothesis, that
pretends to discover the ultimate original qualities of human nature, ought at
first to be rejected as presumptuous and chimerical.6
The method of forming laws based upon observed regularities, using
induction, is adopted wholesale from Newton’s study of the external
4
Sir Isaac Newton's Mathematical Principles of Natural Philosophy and his
System of the World, Translated by Andrew Motte and Florian Cajori (University
of California Press, 1962).
5
For further discussion see: John Biro, “Hume’s new science of the mind”, in
Norton and Taylor (eds.) The Cambridge Companion to Hume (2/e) (Cambridge:
Cambridge University Press, 2009), and Graciela De Pierris, “Hume and Locke on
scientific methodology: the Newtonian legacy”, Hume Studies, 32:2 (2006).
6
David Hume, A Treatise of Human Nature (1739), 1.7-8
4
world, as is the refusal to “go beyond experience” and introduce
metaphysical speculation.
The rejection of hypotheses, in the form of unknown ultimate causes,
is found throughout the Treatise. In the Introduction, he writes:
When we see, that we have arrived at the utmost extent of human reason,
we sit down contented; tho’ we be perfectly satisfied in the main of our
ignorance, and perceive that we can give no reason for our most general
and most refined principles, beside our experience of their reality; which is
the reason of the mere vulgar, and what it required no study at first to have
discovered for the most particular and most extraordinary phænomenon.7
The regularity account of causation provides the best example of this
method, at least on the standard reading of Hume's account of causation.8
On the regularity reading, Hume provides an account of causation that
stops at the limits of experience and declines to postulate underlying
objectively necessary relations–thick connexions, metaphysically robust
causes–this being equivalent to metaphysical speculation.
We may define a CAUSE to be “An object precedent and contiguous to
another, and where all the objects resembling the former are placed in like
relations of precedency and contiguity to those objects that resemble the
latter”.
If this definition be esteemed defective, because drawn from objects
foreign to the cause, we may substitute this other definition in its place, viz. “A
CAUSE is an object precedent and contiguous to another, and so united with it,
that the idea, of the one determines the mind to form the idea of the other, and
the impression of the one to form a more lively idea of the other.”9
As Loeb notes, Hume assimilates causal and inductive reasoning. The
closest Hume gets to Newton’s regulae philosophandi is found in his
discussion of induction in Treatise 1.3.15, about which he writes “Here is
all the LOGIC I think proper to employ in my reasoning; and perhaps even
this was not very necessary, but might have been supply’d by the natural
principles of our understanding.” His fourth rule provides a clear example
of his Newtonianism:
7
Treatise, 1.9.
I do not intend to discuss the sceptical realist interpretations of Hume here, nor
whether these are more in keeping with Newton’s methodology (that is, whether
Newton was committed to the existence of thick connexions).
9
Treatise, 1.3.14.31.
8
4. The same cause always produces the same effect, and the same effect never
arises but from the same cause. This principle we derive from experience, and
is the source of most of our philosophical reasonings. For when by any clear
experiment we have discover’d the causes or effects of any phænomenon, we
immediately extend our observation to every phænomenon of the same kind,
without waiting for that constant repetition, from which the first idea of this
relation is deriv’d.
The project of the Treatise is commonly–and fairly–seen as an attempt
to provide an account of the mind that mirrors the Newtonian account of
the physical world. The mind for Hume is a system remarkably similar to
the physical world; in both, we find an ontology of passive objects, the
behaviour of which are explained by laws, which are in turn discovered
through the observation of regularities. The laws do not go beyond the
mere statement of these regularities.
That Hume’s science of man does not attempt to match the
mathematical rigour of Newton’s physics is well known but worth
mentioning. Equally worth noting is the infrequency of his explicit
references to Newton. James Force, in his 1986 Hume Studies paper,
enumerates a mere eleven mentions of Newton in Hume’s writings.10 The
first he notes comes from the Appendix to the Treatise, in his discussion
of the existence of a vacuum:
As long as we confine our speculations to the appearances of objects to
our senses, without entering into disquisitions concerning their real nature and
operations, we are safe from all difficulties, and can never be embarrass’d by
any question. … If we carry our enquiry beyond the appearances of objects to
the senses, I am afraid, that most of our conclusions will be full of scepticism
and uncertainty. Thus if it be ask’d, whether or not the invisible and intangible
distance be always full of body, or of something that by an improvement of our
organs might become visible or tangible, I must acknowledge, that I find no
very decisive arguments on either side; tho’ I am inclin’d to the contrary
opinion, as being more suitable to vulgar and popular notions. If the Newtonian
philosophy be rightly understood, it will be found to mean no more.
Hume’s endorsement of Newton’s anti-hypothetical method is clear
here, as are his deflationist tendencies. This is the only mention of Newton
in the Treatise.
10
James E. Force, “Hume’s interest in Newton and science”, Hume Studies, 13:2
(1978).
6
As with Hume, Reid makes clear his allegiance to Newton at the outset
of his first major work, An Inquiry into the Human Mind, on the Principles
of Common Sense:
The man who first discovered that cold freezes water, and that heat turns it
to a vapour, proceeded on the same general principles, and in the same
method, by which Newton discovered the law of gravitation and the
properties of light. His regulae philosophandi are maxims of common
sense, and are practised every day in common life; and he who
philosophizes by other rules, either concerning the material system or
concerning the mind, mistakes his aim. 11
And again, this time from his Essays on the Intellectual Powers of
Man:
Sir Isaac Newton, the greatest of natural philosophers, has given an
example well worthy of imitation, by laying down the common principles
or axioms on which the reasonings in natural philosophy are built. Before
this was done, the reasonings of philosophers, in that science, were as
vague and uncertain as they are in most others.12
Reid does not merely acknowledge the influence of Newton; according
to Reid, Newton’s rules provide us with “the only path to the knowledge
of Nature's works”.13 Ernan McMullin labels Reid the “one other
philosopher [besides Hume] who, more explicitly perhaps than any other,
promoted the Principia and Newton's methodological comments thereon
as the unchallengeable authority in philosophy of science”.14 Newton’s
rules are assimilated wholesale into Reid’s philosophical methodology:
The first principles of natural philosophy … are such as these: That similar
effects proceed from the same or similar causes: that we ought to admit of
11
IHM 1.1 (EE 12).
Page references are to the recent Edinburgh edition of the works of Thomas Reid:
An Inquiry into the Human Mind, on the Principles of Common Sense (1764),
Derek R. Brookes (ed.) (Edinburgh: Edinburgh University Press 1997); Essays on
the Intellectual Powers of Man (1785), Derek R. Brookes (ed.) (Edinburgh:
Edinburgh University Press, 2002); Essays on the Active Powers of Man (1788),
Knud Haakonssen and James Harris (eds.) (Edinburgh: Edinburgh University
Press, 2010).
12
EIP 1.2 (EE 40).
13
EIP 2.3 (EE 83).
14
Ernan McMullin, “The impact of Newton's Principia on the philosophy of
science”, Philosophy of Science, 68 (2001).
no other causes of natural effects, but such as are true, and are sufficient to
account for the effects. ... [E]very man of common understanding readily
assents to them, and finds it absolutely necessary to conduct his actions
and opinions by them, in the ordinary affairs of life.15
Reid’s commitment to these principles in his work is explicit.16 He
devotes the third chapter of Essay I to the rejection of hypotheses,
claiming that Newton’s first rule is “a golden rule; it is the true and proper
test, by which what is sound and solid in philosophy may be distinguished
from what is hollow and vain”.17 Throughout his writings, Reid uses the
ban on hypotheses to argue against a wide range of theories: the
neurophysiological account of mental states offered by David Hartley is
but one example.18 Here, Reid rejects Hartley’s suggestion that mental
states such as sensations and thoughts are causally dependent upon
vibrations in the nervous system and brain on the grounds that the method
by which Hartley argues for his theory is mere speculative hypothesis:
Hartley heaps “supposition upon supposition, conjecture upon conjecture,
to give some credibility to his hypothesis”.19 Furthermore, the hypothesis
is inadequate for explaining the data at hand: “We cannot, indeed, shew
how any vibration should produce the sensation of sound”,20 as quoted in
Nichols (2007b)).
Hartley’s theory fails the Newtonian test for Reid on the grounds that it
goes beyond mere observed regularities to claims about true causal
relations. As Nichols emphasises21, Reid took Newtonian laws to be free
from claims about objective necessary relations: such laws concern
observed regularities, nothing more: “when physics shall be carried to the
utmost perfection, there would not be found in the whole science such a
15
EIP 1.2 (EE 40-1).
See Larry Laudan, “Thomas Reid and the Newtonian Turn of British
Methodological Thought”, in Butts and Davis (eds.) The Methodological Heritage
of Newton (Toronto: University of Toronto Press, 1970); Steffen Ducheyne “Reid's
adaptation and radicalization of Newton's natural philosophy”, History of
European Ideas, 32 (2006); and Ryan Nichols, Thomas Reid’s Theory of
Perception (Oxford: Oxford University Press, 2007a) and “Natural Philosophy and
its limits in the Scottish Enlightenment”, The Monist 90:2 (2007b). Nichols notes
inconsistencies in Reid’s application of Newtonian principles (see esp. 2007b); see
below.
17
EIP 1.3 (EE 51).
18
For full discussion, Nichols (2007b).
19
EIP 2.3 (EE 86).
20
EIP 2.3 (EE 86).
21
Nichols (2007b), p. 234-5.
16
8
conception as that of a cause”.22 Claims about true causes have no place in
natural philosophy. Rather, science proceeds in accordance with Newton’s
fourth rule, by forming generalisations based on observation; these
generalisations should not be read as carrying any metaphysically
substantive causal commitments. Metaphysics has no place in science.
Reid’s indebtedness to Newton goes beyond the mere acceptance of his
regulae philosophandi. Paul Wood notes that “[b]y 1729 he was deeply
immersed in the study of the mathematical technicalities of Newton’s
Principia and, for the rest of his life, Reid investigated an array of
empirical and theoretical problems set by Newton in astronomy,
mechanics, and optics”.23 Here we find a picture of Reid as a practising
Newtonian natural philosopher: teaching astronomy from a Newtonian
perspective during his time as regent at King’s College; writing on “the
proper measure of the force of bodies in motion”, and devoting much
energy to the study of optics. Reid’s avowed debt to Newton is not mere
lip-service (and unsurprising given his place within the Gregory family).
It is striking to note the extent to which the two Scots draw explicitly
upon Newton in their respective writings. The natural conclusion to draw
from this is that Reid takes himself to be the more committed Newtonian;
if it is indeed the case that Reid’s overall theory is wholly consistent with
the Newtonian methodology, then so much the worse for Hume.
The naturalist commitments of Hume and Reid
What, though, of the respective naturalist commitments of the two
authors? The naturalist reading of Hume is now very familiar, and I will
not argue for it over traditional sceptical readings here.
Louis Loeb has recently argued that there are far more similarities
between Hume and Reid that ordinarily thought. Despite Reid’s criticisms
of Hume (which Loeb puts down to misunderstandings and an incomplete
reading of Hume by Reid), both end up advocating naturalist positions:
“When Reid defended the legitimacy of the beliefs of ‘common sense’, he
had in view beliefs resulting from unavoidable and universal instinctive
mechanisms, the faculties associated with his ‘first principles’. I think it
fair to say that David Hume, on what is today the received interpretation of
his philosophy, held a position of this sort.”24
22
Thomas Reid, “Of Power”, The Philosophical Quarterly, 51 (2001), p. 7.
Paul Wood, “Thomas Reid and the culture of science”, in Cuneo and van
Woudenberg (eds.), The Cambridge Companion to Thomas Reid (Cambridge:
Cambridge University Press, 2004).
24
Loeb 2007, p. 65.
23
This is clearest, Loeb thinks, when we consider their accounts of
induction–unquestionably the most relevant issue on the matter of their
respective attempts to engage in a scientific study of the mind. He notes
three strands in Reid’s position on induction, all of which he shares with
Hume (whether Reid accepts this or not):
First, Reid takes it that the inductive principle, the belief in ‘the
continuance of the present course of nature’, cannot be founded in
argument or derived from antecedent reasoning. This claim is basic
Humean doctrine.25
The next commonality Loeb draws attention to is the attribution “of
inductive beliefs to human nature”.26 The belief in induction is a first
principle for Reid: “That, in the phenomena of nature, what is to be, will
probably be like what has been in similar circumstances”.27 For Hume,
inductive beliefs are grounded in custom or habit, a natural, irresistible and
unavoidable tendency of the mind. They are “necessary” to “the conduct
of human life”.
For Reid, all first principles are justified due to their basis in human
nature. All of our fundamental beliefs about epistemological sources come
from the “same shop”, whether this is seen as nature or God: we have no
grounds for favouring, say, introspection and reason over sense experience
or induction. All first principles should be accepted or rejected together:
the latter, however, is not a philosophically viable option but is, rather, a
sign of madness or insanity.
Reid does not identify with the Humean account of induction on the
grounds that Hume’s account is wholly sceptical in nature. For reasons
that are understandable, Reid takes Hume to hold custom or habit to be
antithetical to rational justification: the role of the imagination here
undermines any claim that the beliefs might have to be reasonable.
That such beliefs are justified is the third common strand Loeb claims
to find. As noted above, Loeb rejects the sceptical reading of Hume,
finding it disproved “as decisively as possible” in the Hume scholarship
over the last forty years, citing passages such as Hume’s rules for
inductive reasoning in favour of this interpretation.
If we favour the non-sceptical reading of Hume, it can be hard to find
much of a gap between the two philosophers on this matter. This is, of
course, not unexpected given their shared Newtonian heritage. As noted
25
Loeb 2007, p. 66.
Loeb 2007, p. 67.
27
EIP 6.5, EE 489.
26
10
above, the tendency to emphasise the differences comes, in part at least,
from Reid’s characterisation of Hume as the arch-sceptic.
One obvious difference between Hume and Reid relates to their
starting points. Where Hume limits himself to the introspectively-revealed
impressions and ideas, on the grounds that the science of man is the
foundation for all other sciences and should not, therefore, draw upon
them, Reid helps himself to a wider range of sources. When coming to
Reid from a familiarity with Hume, one of the most striking aspects of his
methodology concerns the kinds of evidence upon which Reid draws.
Although introspection is one of the most important sources of knowledge
for Reid, he also draws upon our knowledge of the external world and
from common linguistic usage.
We can see this when we consider the empirical methods by which
Reid identifies his first principles. For Reid, such principles should be
irresistible and embedded in all languages. It should not be possible to
recall when one acquired the belief, nor should it be possible to trace the
origins of the belief in history.28 The evidence, therefore, for a belief to be
counted among the first principles is not drawn from introspection alone; it
comes from all disciplines, including the study of language, the sociological
study of other cultures and languages, evidence from testimony, and
human history: all legitimate sources of evidence for contemporary science.
It is this willingness to admit evidence from such a variety of sources
that leads Maddy to claim that Reid is closer to the contemporary
naturalist than Hume. A similar claim looks possible with regard to the
respective Newtonian merits of the two positions.29 On her view, Hume’s
approach falls short of naturalist standards due to an ultimately unjustified
commitment to what she sees as a foundationalist appeal to introspection.
As Maddy has it, the Humean scientist of man “begins with the stipulation
that all his studies must be founded on the Science of Man and that the
Science of Man itself not only begins from introspection of his
experiences, but begins from such introspection alone, unaided by any
other knowledge of the world, particular or general.”30
Liberty and necessity
Concerning Hume’s account of liberty and necessity, we find him
employing a familiar approach:
28
Cf. Keith Lehrer, Thomas Reid (London: Routledge, 1989), p. 35.
Cf. Ducheyne (2006).
30
Maddy 2011, 12-13.
29
In judging of the actions of men we must proceed upon the same maxims,
as when we reason concerning external objects... No union can be more
constant and certain, than that of some actions with some motives and
characters; and if in other cases the union is uncertain, it is no more than
what happens in the operations of body31.
While his evidence for this approach is hardly exhaustive, Hume does
offer some compelling cases (in amongst less palatable discussion of the
differences between the sexes and the behaviour of “savages”). The bestknown and most striking case is, of course, that of the condemned man:
A prisoner, who has neither money nor interest, discovers the impossibility
of his escape, as well from the obstinacy of the goaler, as from the walls
and bars with which he is surrounded; and in all attempts for his freedom
chuses rather to work upon the stone and iron of the one, than upon the
inflexible nature of the other. The same prisoner, when conducted to the
scaffold, foresees his death as certainly from the constancy and fidelity of
his guards as from the operation of the ax or wheel32.
The most pertinent discussion for the matter of Hume’s Newtonian and
naturalist commitments comes from the following chapter, in which Hume
moves on to the matter of why we think we possess liberty. Hume’s
comments on this false belief–the belief that we possess the liberty of
indifference–are of particular importance for us. He postulates three
reasons “for the prevalence of the doctrine of liberty”:
It is difficult for us to persuade ourselves we were governed by
necessity33
There is a false sensation or experience even of the liberty of
indifference34
[The third reason] proceeds from religion, which has been very
unnecessarily interested in this question35
The first is true enough, but still consistent with the claim that we are
not governed by necessity. We can set the third aside here, as well as
Hume's argument that moral evaluation presupposes the liberty of
spontaneity rather than that of indifference. Of more immediate
31
Treatise, 2.3.1.12.
Treatise, 2.3.1.17.
33
Treatise, 2.3.2.1.
34
Treatise, 2.3.2.2.
35
Treatise, 2.3.2.3.
32
12
importance is the second reason, by which Hume at once recognises and
dismisses the idea that we might possess an impression that could serve to
give rise to the idea of power.
Now we may observe, that tho’ in reflecting on human actions we seldom
feel such a looseness or indifference, yet it very commonly happens, that in
performing the actions themselves we are sensible of something like it:
And as all related or resembling objects are readily taken for each other,
this has been employ’d as a demonstrative or even an intuitive proof of
human liberty.36
Setting aside the fact that Hume never details the mechanism that gives
rise to this alleged feeling (or “something like it”), it is his rejection of the
veracity of the feeling that is important for our present purposes. This is
grounded in his commitments to the Copy Principle and to the thesis that
impressions are wholly passive–“We never have any impression, that
contains any power or efficacy. We never therefore have any idea of
power”37 –as well as his account of causation as constant conjunction.
A rejection of thick connexions (or causal powers in the
metaphysically robust sense) underpins Hume's rejection of one proposed
account of the acquisition of the idea of power in a passage added in the
Appendix. Here, Hume finds only constant conjunction in the relation
between impressions of reflection and their subsequent ideas:
Some have asserted, that we feel an energy, or power, in our own mind;
and that having in this manner acquir’d the idea of power, we transfer that
quality to matter, where we are not able immediately to discover it. The
motions of our body, and the thoughts and sentiments of our mind, (say
they) obey the will; nor do we seek any farther to acquire a just notion of
force or power. But to convince us how fallacious this reasoning is, we
need only consider, that the will being here consider’d as a cause, has no
more a discoverable connexion with its effects, than any material cause has
with its proper effect. … In short, the actions of the mind are, in this
respect, the same with those of matter. We perceive only their constant
conjunction, nor can we reason beyond it.38
While one is not in general aware of the constant conjunctions that
hold between motives and actions in one’s own case–this fact underlies the
36
Treatise, 2.3.2.2.
Treatise, 1.3.14.11.
38
Treatise, 1.3.14.12, Appendix addition.
37
“false sensation” of the liberty of indifference–such constant conjunctions
are accessible to third parties:
We may imagine we feel a liberty within ourselves; but a spectator can
commonly infer our actions from our motives and character; and even
where he cannot, he concludes in general, that he might, were he perfectly
acquainted with every circumstance of our situation and temper, and the
most secret springs of our complexion and disposition39.
One thing to note here is the assumption of determinism: even in cases
where inferences from motives cannot be drawn, it is assumed that this is
in principle possible. Of course, it could be argued that this is an inductive
inference based on a limited base of empirical evidence–those cases
mentioned above–and that Hume's psychological theory is only helping
itself to the same methodological principles available to the rest of science.
While such a claim has some merit, the paucity of the evidential basis
hardly merits such a generalisation.
Reid’s position could not be further from that of Hume: he is
committed to a contra-causal libertarian conception of human agency. On
Reid’s view, the power to perform a certain action consists in the
possession of active power: the ability to act in the relevant way or to
refrain from doing so in one and the same set of circumstances. Reid holds
an agent causalist view of human action according to which the agent is
the true, irreducible cause of her actions only when the following
conditions are satisfied: agent a has the power to x; a exercises that power;
a could have refrained from exercising that power in just those
circumstances. As we have seen, such a commitment goes beyond the
boundaries of science for Reid, in that science ought only to be concerned
with the discovery of regularities; such claims fall foursquare within
Reid’s metaphysics.
When discussing the origins of the conception of power in the opening
paragraphs of “Of Power”, Reid, consistent with his commitment to
broadly Newtonian principles of reasoning,40 rules out three potential
accounts of the source of this conception. Agreeing with Hume, he notes
that power “is not an object either of sense or consciousness”;41 nor does
he wish to accept that knowledge of the full range of one’s powers and of
the effects of exertions is innate. Instead of adopting any such position,
39
Treatise, 2.3.2.2.
See, for example, EIP 1.1 and 1.3. Ryan Nichols questions the extent of Reid’s
commitment to Newtonianism in Nichols (2007b).
41
OP 3. See also EAP 3.1.2.
40
14
Reid holds that it is through experience that we come to learn that we have
the power to affect changes in the body and in the environment, and of the
range of this power:
I am rather inclined to think that our first exertions are instinctive, without
any distinct conception of the event that is to follow, consequently without
will to produce that event. And that finding by experience that such
exertions are followed by such events, we learn to make the exertion
voluntarily and deliberately, as often as we desire to produce the event.
And when we know or believe that the event depends upon our exertion,
we have the conception of power in ourselves to produce that event.42
As Maddy notes, Reid often sounds like a contemporary cognitive
scientist, and we see this here. The passage displays an approach that is
reminiscent of developmental psychology; we do not look for the origins
of the conception of power merely through an introspective process that
seeks to explain its origin in a prior impression of sensation or reflection;
we look to the behaviour of infants in the early stages of growth.
Furthermore, “that we have some degree of power over our actions,
and the determination of our will” is one of Reid’s first principles of
contingent truths, this bringing with it evidence from all the sources
outlined above. This, of course, is a stronger claim and amounts to an
endorsement of the conception of power as accurate with regard to one’s
own possession of active power. We believe that we possess such power,
and we do.
In “Of Power”, Reid offers five considerations in support of the
contention that our possession of active power is a first principle:
The arguments I have adduced are taken from these five topics: 1. That
there are many things that we can affirm or deny concerning power, with
understanding. 2. That there are, in all languages, words signifying, not
only power, but signifying many other things that imply power, such as,
action and passion, cause and effect, energy, operation, and others. 3. That
in the structure of all languages, there is an active and passive form in
verbs and participles, and a different construction adapted to these forms,
of which diversity no account can be given, but that it has been intended to
distinguish action from passion. 4. That there are many operations of the
human mind familiar to every man come to the use of reason, and
necessary in the ordinary conduct of life, which imply a conviction of
42
OP, 3.
some degree of power in ourselves and In others. 5. That the desire of
power is one of the strongest passions of human nature.43
While this might be read as suggesting that first principles admit of
proof, we should note Harris’ correct response to any such suggestion:44
these considerations are not intended to prove a first principle: these are
fundamental and do not admit of proof. Instead, they “show that
philosophy can be brought to bear on the task of distinguishing genuine
first principles from mere pretenders to that status”; they are not for the
purpose of showing that such principles are true. This will be important
when it comes to our final evaluation of Reid’s Newtonian commitments.
The move from naturalism
What explains such a radical divergence? Maddy’s explanation in
terms of Hume’s foundationalist commitment to the science of man as
coming before, and not drawing upon, the other sciences cannot be the
whole story. Reid’s account does, of course, take evidence from the other
sciences but it need not have: an inspection of one’s own mind, including
memories of infancy and childhood, combined with a study of one’s own
linguistic practices, would have shown the same results.
Reid would lay the blame for Hume’s perceived error on his
commitment to the Way of Ideas. This, thinks Reid, is profoundly unNewtonian and leads to a subversion of legitimate forms of evidence:
The structure of all languages is grounded upon common notions, which Mr.
Hume's philosophy opposes, and endeavours to overturn. This no doubt led
him to warp the common language into a conformity with his principles; but
we ought not to imitate him in this, until we are satisfied that his principles are
built on a solid foundation.45
The Way of Ideas, according to Reid, fails the central Newtonian tests:
we have no independent evidence for the postulation of ideas, and they
explain nothing. They are, in other words, mere hypotheses.
[W]e must acknowledge, that, though we are conscious of perceiving
objects, we are altogether ignorant of how it is brought about; and know as
little how we perceive objects as how we were made. And if we should
admit an image in the mind, or contiguous to it, we know as little how
43
OP, 19-20.
Harris 2005, 186.
45
EIP 1.1 (EE 36).
44
16
perception may be produced by this image as by the most distant object.
Why therefore should we be led, by a theory which is neither grounded on
evidence, nor, if admitted, can explain any one phenomenon of perception,
to reject the natural and immediate dictates of those perceptive powers, to
which, in the conduct of life, we find a necessity of yielding implicit
submission?46
Reid here appeals to his familiar themes of darkness and mystery in
our knowledge of the mind to ground his rejection of Humean ideas.
Newtonian science does not allow us to go beyond causal regularities; to
do so is to break Newton’s first rule.
Hume’s rejection of the possession of an idea of power is not
consistent with his broader Newtonian commitments: it is driven by the
Lockean account of the origin of ideas as copies of (as Hume would have
it) impressions and the commitment to a offering a model of the mind that
mirrors Newton’s account of the behaviour of physical bodies as passive,
governed by laws.
Reid’s account of the origin of the conception of power, in contrast,
seems perfectly consistent with his commitment to Newtonian principles:
it is grounded in the two forms of observation discussed earlier and gives a
psychologically plausible, naturalistic account of the origin of the
conception.
It is only when Reid moves outwith what he takes to be the realm of
Newtonian explanation into the domain of metaphysical speculation that
we find his endorsement of a thoroughly un-Newtonian belief in the
existence of active power and the rejection of any notion of causation
other than that involving an agent.47
Nichols draws attention to Reid’s tendency to lay the charge of
forming hypotheses at those works with which he disagrees while allowing
himself to postulate the existence of free will, angels and the souls of
vegetables.48 This charge is not without merit, but it does not by itself
demonstrate that Reid takes an anti-Newtonian line at any point: if these
claims are made outwith the context and domain of Newtonian
explanation, then they are just as legitimate as Newton’s own belief in the
existence of a divine being.
46
EIP 2.14 (EE 178)
It becomes apparent here that even if one is sympathetic to interpretations of
Hume whereby he is committed to the existence of causal powers, the gap between
Reid and Hume is not closed in any way whatsoever.
48
Nichols 2007b.
47
The problem for such a line is that Reid does not adequately delineate
the boundaries of scientific explanation and metaphysical speculation. As
Nichols notes, these can appear to vary depending upon Reid’s sympathy
with the subject at hand.
It is at this juncture that Reid can be charged with a violation of
Newton’s regulae. Loeb argues that Reid’s point blank refusal to admit
reductive accounts of his first principles breaches his Newtonianism and
his naturalism.49 It might be thought that were a psychological account of
the origins of such a belief offered–say, an account that seeks to explain
the acquisition of such a belief in terms of more primitive and general but
empirically legitimate mechanisms (rather than a unique faculty within the
black box of the mind, as Reid would have it)–then we should be at the
very least be willing to entertain it and consider its Newtonian pedigree.
Reid does not do so and appears unwilling to consider such
possibilities. Where Wolterstorff sees this as a sign of Reid’s humility and
piety, and Maddy makes approving noises about Reid’s reluctance to go
beyond the science of the day, Nichols finds a hard-headed and
illegitimate anti-naturalist streak underlying such comments as:50
But how are the sensations of the mind produced by impressions upon the
body? Of this we are absolutely ignorant, having no means of knowing
how the body acts upon the mind, or the mind upon the body. ... There is a
dark gulf between them, which our understanding cannot pass.51
Nichols infers from this and similar comments that “Reid is employing
a double standard on philosophical explanation ... he draws the boundary
between natural philosophy and metaphysics at the place he does in part
because it allows him the conclusions he desires.”52
To read Reid in this way is, however, to go some way towards
misrepresenting him. Reid’s commitment to Newtonianism is only one
aspect of his wider common sense commitments: as Lehrer writes, “the
idea that science and philosophy can stand on their own without the
support of the first principles of the human mind, the principles of
common sense, leads inevitably to scepticism”.53 The study of science for
Reid takes place within a common sense framework: these are not
49
Loeb 2007. See also Nichols 2007b.
Nicholas Wolterstorff, Thomas Reid and the Story of Epistemology (Cambridge:
Cambridge University Press, 2001); Maddy 2011; Nichols 2007b.
51
IHM 6.21 (EE 176).
52
Nichols 2007b, p. 245.
53
Keith Lehrer, “Reid, Hume and common sense”, Reid Studies 2:1 (1998), p. 25.
50
18
different paradigms that one switches between. Common sense is prior to
Newtonian natural philosophy. Newton’s “regulae philosophandi” might
be “maxims of common sense”, but they do not exhaust or lay down the
methodology of the common sense philosopher: this is prior to Newton’s
rules, not subject to them. In his discussion of induction as a first
principle, Reid is explicit on this matter: “I need hardly mention, that the
whole fabric of natural philosophy is built upon this principle, and, if it be
taken away, must tumble down to the foundation.”54
Hume, on the other hand, places Newtonian principles (as he sees
them) at the heart of his methodology. His account of causation is
consistent with a Newtonian framework; the problem arises when he
applies this reasoning to one’s own actions. As we have noted above, it is
in part his commitment to the Way of Ideas that informs his approach to
the idea of power. Hume could legitimately reject the thesis that we are
aware of ourselves as possessing contra-causal agency–especially since
this would appear to require knowledge of counterfactuals–but his
advocacy of determinism and the liberty of spontaneity breaches his
Newtonianism. Such claims fall within metaphysics–every bit as much as
Reid’s agent causal theory does–and are grounded in the assumption that
an account of the mind as passive is available to mirror Newton’s account
of matter as passive. This is not an assumption to which he is entitled by
dint of his Newtonianism.55
54
EIP 6.5 (EE 489).
I would like to express my gratitude to the organisers of the 2011 Moscow
conference, especially Anastasia Yastrebtseva and Ekaterina Vostrikova, for their
hospitality and assistance. Peter Millican and Emilio Mazza are also due thanks for
helpful comments at the paper’s original presentation.
55