Abstract
According to Hintikka's interpretation of the cogito, "I think" is not a factual premise from which we infer "I exist" thanks to the tacit premise "to think, one must be". I think" is not a first thought-content from which a second is inferred ("I am"), but the act of thinking the thought-content "I am": this thought-content is necessarily true from the moment the act of thinking it is performed. It is the act of thinking it (cogito) that implies the truth of the thought content (sum). In this theoretical framework, the self that is unmistakably given in the experience of the cogito is, and is only, the subject of the mental act, inherent in the act in question. The notion of "thinker" or "subject" thus corresponds to a role defined in relation to a mental occurrence, just as the notion of "speaker" corresponds to a role defined in relation to a verbal occurrence.
At this point, we need to consider a well-known objection to the Cartesian cogito: that of Lichtenberg. Is it legitimate to go beyond thought itself, and hypostasize its subject as Descartes does? It's all very well for a thought to occur, but what's to guarantee that this occurrence is attributable to a subject, even if it's myself? Lichtenberg argues that the transition to "I think" is illegitimate, and that we should stick to a simple cogitatur: "it thinks".
Lichtenberg's reply is that, in Descartes, thoughts are defined by consciousness. Thoughts are immediately given to us, and are the object of the mental act of apperception, not contingently, like a sunset that may or may not be observed, but necessarily: a thought would not be a thought if it were not present to the consciousness of the thinking subject. Thoughts are therefore inseparable from the subject of consciousness: the subject of consciousness is the subject to whose awareness thoughts are present, and in whose absence there would be no consciousness and therefore no thought. Thoughts and their subject (in the minimal sense) are given together in the phenomenon of consciousness, and cannot be dissociated. As Hamelin writes, commenting on Descartes, "the fact of being for oneself is not a special act that is added to thought". From this point of view, there is an important difference, strongly emphasized by Cartesians, between being aware of a thought, and thinking about that thought. When we think about a thought, we form a second thought, distinct and separable from the one we're thinking about. But, as Brentano would later point out, awareness of a thought is not a second thought, but the thought itself as conscious.
