certainty of cogito

The Certainty of Cogito

by
Dr. Laxminarayan Lenka
Department of Philosophy,
North-Eastern Hill University,
Shillong, India,Pin-793022
lenkanehu@yahoo.co.in

1. Why was Descartes in search of certainty?

He was a traditional foundationalist. He made a distinction between philosophy and sciences other than philosophy with the understanding that a philosopher’s job is to find some basic truths on which the superstructure of all other science is to be built on. Further, in accordance to this understanding, if the foundation happens to be corrigible and uncertain then the superstructure based on that foundation cannot be incorrigible and certain as much as a weak foundation of a building cannot hold a strong and heavy superstructure. As we need our scientific knowledge to be reliable and reliable only if it is certain, we must find some basic principles no less than certainty. Hence, Descartes was after certainty.

Note that
he was so much obsessed with his search for certainty, he was not ready to accept that nothing qualifies certainty unless it is found with certainty that nothing qualifies certainty.

2. How did he approach to certainty?

He approached to certainty through his method of doubt.
The idea is simple. He identified certainty with indubitability, that is, what cannot be doubted. Then, explored into different types of beliefs in order to examine if they can be doubted. Finally, what he could not doubt became, for him, the indubitable truth or the truth with certainty.
The Cogito Principle, that is, I think , therefore, I am, is that truth with certainty.

3. How is the Dream Argument significant in the search for certainty?

The dream argument is employed to demonstrate that, at one go, we can doubt on the truth of all propositions expressing our beliefs based on sense experience.
None that we claim to know through our sense perception is certain- this Dream Argument is supposed to prove.
How?
The argument has a crucial assumption that there is no mark of distinction between the waking state and the dream state. With this assumption, it is concluded that we can doubt on anything we perceive through our sense, since we can doubt on anything that we perceive in a dream.
For example,
I see in my dream that I am reading a book. It is false that I am reading a book, as I am actually sleeping. If there is no difference between my dream state and my waking state, then, even if I am in the waking state it is doubtable that I am in the waking state. Consequently, it is doubtable that I am reading a book even if I am actually reading a book in my waking state. If I believe in my waking state that I am reading a book, and I am reading a book, the said belief is not certain and it is doubtable. Who knows, I might be just dreaming and not actually reading a book, insofar as there is no mark of difference between the two states.

4. How is the Demon Argument significant in the search for certainty?

Whereas the Dream Argument is employed to doubt on knowledge claims based on sense perceptions, the Demon Argument is employed to doubt on truths of arithmetic, geometry and even the so-called logical truths. By this argument we can doubt on every simple truth that does not come under the purview of doubting on the basis of the Dream argument.
For example,
even if it might be false that I am not seeing an apple when I see an apple in my dream, it is true that an apple has a shape and size. That the apple has a shape and size is true when I see it in my dream, it is also true when I actually see it. Therefore, even if there is no difference between the two states, the Dream Argument does not suffice me to doubt that an apple has a shape and size. Similarly, 2+2 is equal to 4 is true both in my dream and in my waking state. The truth of 2+2 is equal to 4 cannot be doubted by means of Dream Argument. It can be doubted by means of the Demon Argument.
How?
The Demon Argument goes like this.
Imagine that there is such a powerful but deceitful demon that he has full control over our body and mind and that even if it is ~p he makes us believe that it is p. For example, even if 2+2 is not 4, the demon has made us all to believe that 2+2 is equal to 4; even if there is no apple in reality, the demon has made all arrangements for us to believe that an apple has a shape and size.

Note that
the point is not that whether such a demon really exists or not. It is true that such a demon does not exist. The point is whether we can imagine or conceive of such a demon being there.
Insofar as we can conceive of such a demon, it is proved that we can conceive of the falsity of those simple truths under consideration. Now, where ever such a falsity is conceivable, there we can be assured of certainty; the truth of the belief under consideration becomes doubtable.
This is how the Demon argument works in enabling us to doubt on simple truths which we cannot doubt by means of the Dream Argument.

5. Is the Cogito Principle certain in the sense that a logical truth is certain?

No. Even a logical truth is subject to doubt by Descartes’ Demon Argument. Therefore, the certainty of cogito ergo sum cannot be identified with the certainty of a logical truth. In other words, I think, therefore, I am is not a logical truth.

Secondly, neither I think nor I exist is a logical truth.
It is not necessarily true that I think. Because, I might not be thinking. This becomes clear if you replace “I” by “Lenka”. “Lenka is thinking” is not a necessary truth. Nor is it necessarily true that Lenka exists. One hundred years back, it was false that Lenka exists and false that Lenka is thinking. But a necessary truth is true now as well as one hundred years back, it never becomes false. (following A.J. Ayer)

6. What does the “therefore” in “I think, therefore, I am” mean?

There are at least four different interpretations on the meaning of the above said “therefore” in accordance to four different interpretations of the meaning of “I think, therefore, I am”.
(a) “I thin therefore I am” has an implicit major premise of a syllogistic argument one can advance in support of “I think therefore I am”. The implicit major premise is
Any thing that thinks does exist
And the argument is
Anything that thinks does exist
I think
Therefore, I exist
(b)”I think, therefore, I exist” is an inference in the sense that “I think” implies “I exist”. It is not a syllogistic inference because, as we cannot claim the certainty of “Anything that thinks does exist”, we cannot claim the certainty of “I exist” based on the above-cited syllogistic argument.
Why cannot we claim the certainty of “Anything that thinks does exist”?
To claim its certainty, we need to be certain about at least one subject that if it thinks then it exists. The one subject may be either somebody other than myself or I myself. If it is I myself, then, it leads to the fallacy of begging the question. That is, I am supposed to prove that I think therefore I exist and have already presupposed that I think necessarily implies that I exist. On the other hand, if the subject is other than me, it leads to an intuitively unacceptable situation. Namely, that I know that other thinking beings do exist before I know that I myself is an existent thinking being.
Now, as the “therefore” is not referring to a syllogistic inference, it must be an inference of what follows it from what precedes it. That is, it an inference one can rewrite as
I think implies I exist.
The advantage of this understanding is that we obtain the certainty of I exist from the certainty of I think.

(c ) It is an inference, neither syllogistic nor implication, but a presupposition.(Bernard Williams)

What is the difference between an implication and a presupposition?
The fundamental difference between the two is that the rule of modus tollens works with respect to implication, it does not work with respect to presupposition. For example, in the argument

My kids are in the school implies that my kids are not in my school.
My kids are in my house.
Therefore, my kids are not in the school

We have used modus tollens to infer the conclusion from the premises.
Similarly, if we use modus ponens to
My kids are in the school presupposes that I have kids
I have no kids
And infer that My kids are not in the school.
This would be wrong. Because, the conclusion (my kids are not in the school) presupposes that I have kids whereas it is already asserted in one of the premises of the same argument that I have no kids. Thus, if we allow modus tollens to hold with respect to presupposition, we assert a contradiction, namely, that I have kids and I have no kids.

Note that
We can infer I have kids
as well as My kids are not in the house
from that My kids are in the school,
though in the first instance of inferring is due to a presupposition
and the second is due to an implication. That is, we infer I have kids because My kids are in the school presupposes that I have kids. We infer my kids are not in my house because My kids are in the school implies my kids are not in the school.

Now, even if we accept the said difference between implication and presupposition, why should we take the Cogito principle for an inference in the sense of a presupposition and not in the sense of an implication? Secondly, why at all we take it to be an inference when we know that knowledge of my own existence is there with me without my knowledge of my own thinking? If q is inferred from p, then, knowledge of q is based on the knowledge of p. How do I know the truth of q without knowing the truth of p, if I infer q from p?

Answer(in accordance to Bernard Williams):
Even if we we do not know the truth value of q and thereby do not know the truth value of p&q, we can very well infer that it is p if it is p&q. Inferring of p from p&q does not demand that we must know the truth of p&q prior to our knowing that p. Similarly, inferring of I exist from I think does not demand that we must know I think prior to our knowing that I exist. Therefore, it is quite possible that we know that I exit before we know that I think and yet we infer I exist from I think.

The advantage of holding the ‘therefore’ as a presupposition rather than an implication is that we can interpret “I think” to be certain on the basis of the infallible reference of “I”.

(d) It is not an inference of any sort; it is a performance. (J. Hintikka)