Cogito ergo sum: Encyclopedia - Cogito ergo sum

Cogito ergo sum

René Descartes' Latin statement "cogito, ergo sum" (traditionally translated as "I think, therefore I am", but more accurately as "I am thinking, therefore I exist") is possibly the single best-known philosophical statement. "Cogito ergo sum" is a translation of Descartes' original French statement: "Je pense, donc je suis", which occurs in his Discourse on Method.

Although the idea expressed by "cogito ergo sum" is most commonly associated with Descartes, it was present in many of his predecessors, especially Augustine of Hippo in De Civitate Dei (books XI, 26), who offers this argument, and anticipates modern refutations of it.

See Principles of Philosophy, §7: "Ac proinde haec cognitio, ego cogito, ergo sum, est omnium prima et certissima etc."

Cogito ergo sum - Introduction

The phrase "cogito ergo sum" is not used in Descartes' most important work, the Meditations on First Philosophy, but the term "the cogito" is (often confusingly) used to refer to it. Descartes felt that this phrase, which he had used in his earlier Discourse, had been misleading in its implication that he was appealing to an inference, so he changed it to "I am, I exist" (also often called "the first certainty") in order to avoid the term "cogito".

At the beginning of the second meditation, having reached what he considers to be the ultimate level of doubt – his argument from the existence of a deceiving god – Descartes examines his beliefs to see if any has survived the doubt. In his belief in his own existence he finds it: it is impossible to doubt that he exists. Even if there were a deceiving god (or an evil demon, the tool he uses to stop himself sliding back into ungrounded beliefs), his belief in his own existence would be secure, for how could he be deceived unless he existed in order to be deceived?

There are two important notes to keep in mind here. First, he only claims the certainty of his own existence from the first-person point of view — he has not proved the existence of other minds at this point. This is something that has to be thought through by each of us for ourselves, as we follow the course of the meditations. Secondly, he is not saying that his existence is necessary; he is saying that if he's thinking, then he necessarily exists (see the instantiation principle).

It should also be noted that Descartes does not use this first certainty, the cogito, as a foundation upon which to build further knowledge; rather, it is the firm ground upon which he can stand as he works to restore his beliefs. As he puts it:

Perhaps what Descartes meant, simply put is "I am vividly aware of my existence".

Cogito ergo sum - Criticisms of the cogito

There have been a number of criticisms of the cogito. The first of the two under scrutiny here concerns the nature of the step from "I am thinking" to "I exist". The contention is that this is a syllogistic inference, for it appears to require the extra premise: "Whatever has the property of thinking, exists", and that extra premise must surely have been rejected at an earlier stage of the doubt.

It could be argued that "Whatever has the property of thinking, exists" is self-evident, and thus not subject to the method of doubt. This is because it is true that any premise of the form: "Whatever has the property F, exists", but within the method of doubt, only the property of thinking is indubitably a property of the meditator. Descartes does not make use of this defence, however; as we have already seen, he responds to the criticism by conceding that there would indeed be an extra premise needed, but denying that the cogito is a syllogism.

Perhaps a more relevant contention is whether the 'I' to which Descartes refers is justified. In Descartes, The Project of Pure Enquiry Bernard Williams provides a history and full evaluation of this issue. The main objection, as presented by Georg Lichtenberg, is that rather than supposing an entity that is thinking, Descartes should have just said: "there is some thinking going on". That is, whatever the force of the cogito, Descartes draws too much from it; the existence of a thinking thing, the reference of the "I", is more than the cogito can justify.

Williams provides a meticulous and exhaustive examination of this objection. He argues, first, that it is impossible to make sense of "there is thinking" without relativising it to something. It seems at first as though this something needn't be a thinker, the "I", but Williams goes through each of the possibilities, demonstrating that none of them can do the job. He concludes that Descartes is justified in his formulation (though possibly without realising why that was so).

Cogito ergo sum - Williams's argument

Whilst the preceding two arguments against the cogito fail, other arguments have been advanced by Williams. He claims, for example, that what we are dealing with when we talk of thought, or when we say "I am thinking", is something conceivable from a third-person perspective; namely objective "thought-events" in the former case, and an objective thinker in the latter. The obvious problem is that, through introspection, or our experience of consciousness, we have no way of moving to conclude the existence of any third-personal fact, verification of which would require a thought necessarily impossible, being, as Descartes is, bound to the evidence of his own consciousness alone.

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