In the history of philosophy, Descartes’s Cogito ergo sum or I think therefore I am has an important place in his search for indubitable knowledge. Descartes finally identifies this sentence as an Archimedean point for constructing a strong basis for the sciences and he eliminates the radical skepticism created by the deceiver argument in the First Meditation. We see that, especially in the Second Meditation, without stating the Cogito explicitly, Descartes declares that “thought” belongs only to him and he defines himself such as “thinking I”, “thinking substance”, “thinking existence”. In doing so, he discovers the relationship between thought and existence. However, he does not hesitate to describe his “I” or self as something mysterious. Thus, it has been observed that there is extensive discussion in the literature about the nature of this “I” or self. Besides that, the Cogito argument has been argued since the time of Descartes as whether it is an inference, a syllogism or a performance and this discussion will be mentioned through Objections and Replies in the “Introduction” part of this article. Moreover, Jaakko Hintikka claims that the Cogito argument is not an inference but it is a performance. Does Descartes consider it as a syllogism, an inference, or a performative act?

In this article, firstly, the function of the Cogito argument will be presented, and then throughout The Second Meditation, the sub-arguments of the Cogito argument will be addressed by analysis of Anthony Kenny. Later, Hintikka’s assertions about performative character of the Cogito argument will be discussed. In addition, the function of “I” and the question of “whether Cogito is an inference or not” will be discussed through the lens of some philosophers who belong to tradition of analytic philosophy. Let us briefly mention which commentators will be considered in this article.

First, we will mention Anthony Kenny’s analysis of the structure of Cogito in the Second Meditation, as Kenny clearly outlines the sub-arguments of Cogito and discusses them in detail. Kenny emphasizes that the term “I” is not even clear after Cogito ergo sum, whereas “thinking” is clear, and that the conclusion of Cogito is not merely “I exist” but “it is true that I exist”. He also refers to Bertrand Russell’s comment that states the use of “I” is superfluous and, in fact, does not refer to any specific entity and datum. According to Kenny, Descartes would be likely to accept that “I” it is not a datum, as he would regard the Cogito argument as an inference. 

Thus, the issue will be addressed by examining whether the Cogito is an inference or, as Jaako Hintikka suggests, a performance. Hintikka argues that Cogito ergo sum is not a valid inference and supports his claim with examples involving Hamlet and Homer. However, these examples are weak and unconvincing. It is worth noting that most of the commentators we consider criticize Hintikka’s analysis. Next, we will consider Peter Geach and Ayer who both discuss the situation of “I” in the Cogito argument and maintain that the “I” in the Cogito does not have to refer anything. Ayer further argues that “I exist” already is accepted by Descartes as true, and therefore does not need to be inferred from the Cogito. According to Ayer, Descartes chose the Cogito argument precisely because its negation implies “I exist” already. Ayer thinks that the primary error in the Descartes’s thought lies in his method of deduction.

Then, we will consider James Carney’s comment. Carney asks that although Descartes postpones whether his mind is physical or not to Sixth Meditation, why do Hobbes, Ayer and Hintikka claim that it is not physical and this is shown in the Second Meditation? Carney thinks that in the Second Meditation, Descartes defines himself as “thinking existence” and this definition causes these philosophers think that Descartes accepts his mind as something not physical. Carney stresses that by defining himself as a “thinking existence”, Descartes already clarifies his “I” and he explains how Descartes’s justification about physical objects do not belong to “I”. Carney thinks that it would be wrong to infer that through “I”, that means conscious mind and Descartes rashly infers his existence from his thinking, the idea as claimed by Hobbes and Hintikka. And then we will consider Harry Frankfurt’s comments especially about Hintikka’s analysis. Frankfurt accepts that the Cogito argument has a performatory character but he also claims that it is an inference. Frankfurt thinks that Hintikka is not successful at demonstrating the performatory character of the Cogito argument and he claims that a valid inference can be found in the Second Meditation. Then we will mention Edwin Curley’s comments on the Cogito argument. We think it is interesting to note Curley’s claim because he also thinks that the Cogito argument is both an inference and a performance. Lastly, we will mention Turkish philosopher Mehmet Emin Erişirgil who stresses that Descartes’s effort to eliminate confusion about whether the Cogito argument syllogism or not. Erişirgil thinks that this confusion is due to his usage of “ergo” in the argument but he also stresses that the Cogito argument enables Descartes with strong foundation in his philosophy. Through all these comments, we will also add our comments and will try to give the reason why the Cogito argument in the Second Meditation, is both an inference and a performance.