Comments and Criticisms on Meditation II
I think therefore I am
The Cogito had a revolutionary implication for knowledge. What Descartes argued
was that certainty about things could only to be derived from subjective certainty.
This turned on its head the common-sense idea that we can be more certain of what
we can agree on objectively with other people than what we think of by ourselves.
For example, if we all agree that an object is round and red this seems more certain to
be true than if only I (subjectively) think the object is round and red. Here was an
argument to say this was not the case.
This shift of certainty from the objective to the subjective has seismic implications – it
puts the emphasis on true knowledge being discovered through reason rather than
through observations on how the world appears through our senses, i.e. the rationalist
approach is preferable to that of the empiricist.
You will remember that the empiricists already have one argument that can resist
Descartes’ leading us down the path of scepticism to the Cogito in the first place.
This is their claim that we can rely on our senses to give us reliable knowledge (the
Counterfeit Coins Argument). We have also seen that Descartes can, in turn, resist
this argument by insisting that he is looking for indubitability rather than ‘as certain as
we can be’.
A different objection to the Cogito (due to Kant) is that Descartes cannot even
formulate the statement itself without there already being concepts (i.e. knowledge) in
place in his mind in the first place. When Descartes says I think therefore I am he
must already know what thought is, what existence is, what logical entailment is.
How can he know these things with certainty? Kant says that he cannot know these
things and so the very foundation on which he rebuilds his world of knowledge is not
secure at all.
Another objection (due to Wittgenstein) is that Descartes has made a mistake in
claiming this as knowledge. Knowledge excludes alternative possibilities. If I know
an object is round this excludes the possibilities of it being square, oblong, etc. If
there are no other possibilities to exclude, then something cannot count as knowledge.
Now Descartes is claiming ‘I know that I think’. But, Wittgenstein says, it is
meaningless to have the possibility ‘I do not know that I think’ as a candidate for
exclusion since this is an impossibility. Hence, ‘I know that I think’ is meaningless
with respect to knowledge and, as such, cannot be the foundation for all knowledge.
A further worry about the Cogito is the way Descartes moves from the I think to the
conclusion I am (or I exist). To perform this movement legitimately, it appears that
there must be a suppressed premise involved:
1. I think
(2. All thinking things exist)
Therefore, 3. I am.
How can Descartes know for certain that all thinking things exist? If he cannot know
this for sure (and how could he?) then he cannot know the Cogito.
Descartes has a reply to this objection: he says that the Cogito is not a syllogism (such
as that illustrated above). He is not claiming to know that ‘all thinking things exist’.
All he is claiming is one particular piece of knowledge: that since he is thinking then
he must exist to do this thinking, i.e. he is an instance of the universal ‘all thinking
things exist’. Unfortunately, in other works Descartes rather muddies the waters by
saying that the Cogito is a syllogism after all which indicates that even he was not
totally clear about where the knowledge of ‘all thinking things exist’ comes from.
He does have another possible reply, however. He might claim that his knowledge of
logical principles (such as the Law of Non-contradiction which says that you cannot
have p and not-p at the same time) is the same type of thing as the Cogito: it is
intuitively obvious that, in such cases, the particular and the universal are inextricable.
Apprehending either comprehends both.
A final objection to the Cogito is that Descartes is not justified in claiming knowledge
of the ‘I’ in question. He can claim the more general ‘there is thought going on’ and
from this infer that there is a thinker to have this thought but how can he know that
this thinker is identified with Descartes’ self (the ‘I’ he refers to)? It is not at all clear
how he can know (as, from the rest of the Meditations he clearly thinks that he does
know) that this I of the Cogito is a continuing identity. He cannot know, for instance,
that he is not ten thinkers thinking in unison. This objection stems from the way that
Descartes conceives of substance as an enduring stuff to which attributes become
attached.
Substance
Descartes is a substance dualist. Not only does he hold that mind and body are
incommensurate, he holds that they are two different substances. The notion of
substance needs clarification here for us to see why there are very few substance
dualists left in the world.
Descartes adopted Aristotle’s definition of substance. The notion is that a substance
is the stuff to which properties are attached. Properties include things like shape,
hardness, colour, taste, etc. Thus a chair will have certain properties: hard, wooden,
4-legged, brown, and so on. Now properties can change but it is clear that they
cannot exist all by themselves: take an old, brown chair – the property ‘old’ cannot
exist all by itself (without the chair or anything else), and neither can the property of
‘brownness’. Thus, a property like ‘old’ must be attached to something if it is to have
meaning. Now, since we know that properties can change, and since we also know
that there is something permanent about a thing like a chair, it seems that this
‘something’ cannot be a property i.e. it is essential to existence. This property-less
something Aristotle called a substance.
Descartes regarded the essential substance of material things to be extension
(occupying a certain amount of space) and of mind to be thought.
The preoccupation with substance as a thing has been considered a mistake for two
main reasons. Firstly, we never encounter (physically or mentally) substances
without their accompanying properties. So, for example, when we apprehend an
apple, we do not apprehend it as the total sum of its properties (it weighs 30g, it’s red
and green, it’s roundish, etc.). Rather, we assign it whole to the category ‘apple’.
Questions of what is left after taking away mass, colour, shape, etc. are mistaken since
this is not how the object is conceived in the first place.
The second reason is that we can easily have objects with properties which clearly do
not attach to a substance but such objects do have existential status. An example
would be the Fiat Uno. Notice that there are lots of ‘a Fiat Unos’ but these are just
examples of the Fiat Uno. A car critic can talk about the top speed, engine capacity,
streamlining, acceleration, shape, etc., etc., of the Fiat Uno. But it would be absurd to
ask him to show you the Fiat Uno. The Fiat Uno does not exist except as
examples/drawings/specifications/thoughts. In other words, there is no substance but
there are properties of the car. Thus, the pressing logic which seemed to demand the
existence of substance as a bedrock on which properties reside is an unnecessary
complication (since there is no way of discovering such a substance empirically and
rationality does not find it a necessary condition).
Mind/Body Dualism
Returning to the Cogito, Descartes has used it to claim that he is, in essence, solely a
thinking thing. The argument he produces in Meditation II runs along these lines:
1. I can imagine that my body does not exist.
2. I cannot imagine that my mind does not exist.
3. Identical objects have identical properties.
Therefore, a) my body and my mind are not identical,
and b) my mind is the only thing I know.
The objection to conclusion a) is that Leibniz’ Law (premise 3) does not hold for
psychological verbs like ‘want’, ‘believe’, ‘imagine’. Descartes’ argument has the
same form as:
1. I can disbelieve I am a teacher at Sevenoaks School.
2. I cannot disbelieve I just wrote this sentence.
Therefore, whoever wrote that sentence is not a teacher at Sevenoaks School.
Clearly, this is wrong. The mistake comes in expecting agreement between mental
states concerning the world and real states of the world. These do not (or may not, or
cannot?) have identical properties.
The objection to conclusion b) is that it is invalid. Descartes cannot know that he is
solely a thinking thing. Sure, he can claim that he knows he is thinking but, for all he
knows, he might also have a body as well as a mind. The Cogito does not rule this
out as a possibility at all.
Knowing one’s own mind
Descartes is rather generous with what counts as thought. Not only does he include
thoughts like those about logic, mathematical objects and relations and so on. He also
includes his imagination, his will and his sensations, in fact ‘all things that we are
immediately conscious of’. Once the thought is conscious, in other words, it is
incorrigible (immune to error).
An initial objection to this is that there do appear to be conscious thoughts that people
have about which they are wrong. For example, people may be convinced that they
are in love when, in fact, it turns out that this psychological certainty is wrong and
they are not in love at all. So perhaps Descartes should not include all conscious
thought in his category of knowledge that is immune to doubt.
But if consciousness of thought is not a criterion, what can be included in Cartesian
certainty of mind? A contemporary critic (Hobbes) pointed out that Descartes’
definition of thought being ‘anything of which we are immediately conscious’ does
not clarify anything. His objection is to ask whether the consciousness of a thought is
identical to the thought or different to it. The horns of this dilemma are:
1. if consciousness of a thought is identical with that thought then it is no different
from the thought itself and so cannot be used as a defining property of the mental.
2. if consciousness of a thought is different from the thought, then an infinite regress
is generated: if I have the thought of x then I must be conscious of x, but this
consciousness of x is also a thought, and so there must be a further thought, that I am
aware of x, and so on ad infinitum.
Since Descartes cannot accept either of the horns of this dilemma, it demonstrates that
his concept of consciousness as a defining character of the mental is suspect.
The Wax Argument
The purpose of this argument is to establish that, contrary to common-sense
empiricism, the mind is more distinctly known than ideas derived from senseexperience.
His piece of wax has a colour, taste, scent, feel and sound when struck. These
properties are all changed when the wax melts, and yet no-one would deny that it is
the same piece of wax as before. So what attributes, besides the ones listed above,
does the wax have? Descartes says that the only attributes left are extension,
flexibility, and being movable.
The attributes of flexibility and movement are ones about which he cannot claim to
have any knowledge derived through his imagination (or senses). This is because he
conceives that the wax can take any shape, can be moved to any place. In other
words, it has a potential infinity of shapes and positions. The same goes for
extension: the wax occupies a certain volume when solid, a larger volume when
liquid, a still larger one when boiled and, on further heating, a yet greater one up to
infinity. In other words, he conceives of an infinity of volumes for the wax.
Now, he says, the imagination is not capable of apprehending infinity. This
apprehension is simply an intuition of the mind: something that is seen clearly and
distinctly when thought about carefully. When this sort of thinking is done, we gain
certainty because we are using our understanding, our reason. It is when we use our
faculty of judgement rather than our bodily senses that we arrive at certainty. Thus it
is that the contents of our minds are more easily known than our bodies: we can be
certain of the former but not of the latter. A human can know more about the wax
(and all other physical things) through the process of reasoning than by the mere use
of bodily senses (like, say, a dog watching the wax melt – it cannot know the wax
better because it’s knowledge is limited to its bodily senses: it has no mind).
An initial objection (due to Quinton) is that objects like the wax are never ‘just
extension’ but that they always with some observable attribute. In other words, it is
not just extension that is essential to objects but also other attributes like colour, or
tangibility – and these are apprehended through the senses. However, there is no
argument offered in favour of this claim and, at the very least, there is no
contradiction or inconsistency in Descartes’ argument that a substance is invisible and
untouchable [but see the discussion of ‘substance’ above].
A different criticism (due to Descartes’ contemporary, Gassendi) is that Descartes has
failed to fully establish that the mind is better known than the body. To really know
something requires something like a qualitative explanation of it. Using wine as an
example, it is not enough to say of one’s conception of a Fine wine as superior to
plonk that it is ‘liquid, pressed from grapes, red, inebriating’ and the like – these terms
are far too general. What is required to distinguish them is some sort of in-depth
analysis of flavours, sweetness/acidity balance, etc. to truly identify where the
difference (and hence the superiority) lies. Gassendi points out that we have a lot of
detailed explanation for the body but that Descartes never offers any comparable
characterisation of the mind – in fact, his description is merely negative: it occupies
no space, it is intangible, invisible, has no weight, and so on. Thus, he cannot claim
that the mind is better known.
In reply, Descartes can argue a) that the mind has a unique range and variability in its
capacity to perceive (in contradistinction to mere animals) – something which the wax
argument has established. And b) that such a mechanistic explanation (like that
carried out for the body) of the mind is ruled out because the mind is a different sort
of thing altogether (a different substance for Descartes). Finally, he can claim that the
mind is absolutely transparent to itself – that it has no ‘hidden constitution’ like
material things have so it is unanalysable.