Cogito, Ergo Sum? | Issue 160

Tallis in Wonderland

Raymond Tallis has a long-postponed meeting with M. Descartes.

René Descartes (1596-1650) has been a conspicuous absentee from this column. Well, here he is at last, uttering perhaps the most famous sentence in Western philosophy: Cogito, ergo sum, or ‘I think therefore I am’. This rather odd statement of the seemingly obvious was prompted by a search for something beyond the reach of doubt, as Descartes describes in his Meditations on First Philosophy (1641).

As to the grounds for pervasive doubt, Descartes tells us he’s had experiences in dreams very similar to those when he was awake. When he was dreaming, he believed that the dreams corresponded to reality. As he expresses it in the Meditations, “there are never signs by means of which being awake can be distinguished from being asleep.” While dreams are transient, and he recognized them for what they were when he woke up, Descartes argues that “it is prudent never to trust completely those who have deceived us even once.” That is no less true when the person by whom we have been deceived is ourselves. Since what passes for waking experience may be a dream, it is entirely reasonable to doubt everything.

Well, not quite everything. One thing I cannot doubt, he continues, is that I am thinking; because to doubt that I am thinking requires that I should be thinking. Since anything that thinks – and that includes by doubting – must exist, I-the-thinker must exist, and I cannot doubt this without self-contradiction. Even if I were dreaming that I was rehearsing the cogito argument, its conclusion – that I am – would still hold up. Hallelujah!

Therefore I Am What?

But what does Descartes’ cogito argument really deliver? Why, for a start, does it begin with thought? Why not ‘I itch, therefore I am’? A non-existent being could not itch. Or what about ‘I dream, therefore I am’? A non-existent being could not entertain dreams. So why did Descartes privilege thought? Was it because thinking was closer than itching or dreaming to the kind of entity he thought himself to be – namely a thinking thing (res cogitans)? Perhaps he chose thought as his starting point for the journey out of scepticism because it was thinking that got him into scepticism in the first place. More to the point, it is possible to think one is not itching without running into self-refutation, but not that one is not thinking.

Descartes’ incontrovertible thought that he is thinking doesn’t, however, seem to place much of his existence beyond doubt. Which is disappointing. After all, Descartes wanted to be sure of his own existence, not just that of the existence of anyone or of any thinking being’s existence, or indeed of anything. This highlights how slim are the pickings from Cogito, ergo sum.

The physicist, philosopher, and wit Georg Christoff Lichtenberg (1742-1799) argued that all Descartes could legitimately conclude from observing his thinking is that ‘there is thinking going on’. Granted, you cannot be aware of thoughts unless you are the individual thinking them, but that alone will not take you all the way to an ‘I’ who does the thinking. Descartes reaches ‘I am’ at the end of the argument only if ‘I’ is in place at the beginning, in ‘I think’. So the cogito argument boils down to “If it is an ‘I’ that is thinking – if the thinking is a manifestation of a whole ‘I’ – then my thinking proves that I am.” But the ‘I’ doing the thinking is not packaged into the mere fact that, as Lichtenberg put it, ‘thinking is going on’. Listening in to thoughts does not therefore deliver the existence of the Man in Full: René Descartes the soldier, mathematician, philosopher, fencer, teacher of Queen Christina, etc. Nor does the reassurance the cogito argument provides extend beyond Descartes into the world he thought he lived in. It doesn’t even deliver his own body, notwithstanding that, as he argued, he is not in his body as a pilot in a ship; he’s more entangled with it than that. You don’t get from ‘there is thinking’, to ‘there is a thinker’, and thence to ‘there is a thinker called René Descartes’, and that that thinker is an embodied subject who has been living a certain life. Or not at least without adding assumptions not delivered by the famous sentence. Some of those assumptions, as I said, are smuggled in via the left-hand side of the argument: they are baked into cogito before we mobilise the ergo.

Perhaps not all the smuggling is entirely unjustified. An entity who can think ‘I think’ must have the capacity for articulate thought, for self-reference, for thought about thought, and (as the performance of the argument itself indicates) for drawing inferences. Whether this amounts to an embodied subject who has a full-blown biography is moot. It remains unclear how many predicates could be logically attached to the bare existence of the thinker – how substantial is the ‘am’ of his conclusion – or whether, indeed, ‘am’ is justified, given that ‘am’, unlike ‘is’, cannot be confined to the bare existence of an entity with only a handful of predicates. It appears that one introspected episode of thought is required to do some implausibly heavy lifting if it is to deliver the full Descartes and at least some of the world he normally believes in.

Descartes is of course aware of how little his cogito argument delivers. As he admits, it does not deal with the concern that he might be the victim of an evil demon who is deliberately deceiving him so that everything else he believes is untrue. To pre-empt that possibility, he invokes a benign God who would not deliberately deceive him or allow him to be deceived about what he calls ‘clear and distinct ideas’.

The best-known argument in Western philosophy seems, therefore, to deflate on close inspection. The episode of thinking fed into the opening of the argument does not deliver something as substantial as a particular thinker or an external world. And although the argument seems like an inference – and an irresistible one at that – it is no such thing, notwithstanding the ergo overseeing the transition from ‘I think’ to ‘I am’. The passage from premise to conclusion depends on assumptions buried in the premise, which are not necessarily immune to the universal doubt from which Descartes is trying to escape.

Performing Thinking

Such concerns have prompted some philosophers (most notably the Finnish philosopher Jaakko Hintikka in his classic ‘ Cogito, Ergo Sum: Inference or Performance?’ Philosophical Review, 1962) to re-think what Descartes was up to. Notwithstanding the ergo, Cogito, ergo sum should not be judged as an argument on paper but as a performance. Any underpinning of substantive truth is to be found not in the mere abstract phrase, but in the speech act by which it is asserted at a particular time and place. What the cogito argument does, then, is to highlight not a logical, but an existential, necessity. This is not located in sentences in the abstract, but in actual statements made – or thought – by someone referring to himself as ‘I’. Descartes’ assertion that he exists is self-evidencing, given that any claim he may make to this effect requires that he should exist in order that he should be able to make it. Moreover, what is delivered by a live performance is a subject with the qualities of a human being capable of arguing like a philosopher.

Whether the ‘I think’ input into the cogito performance is an embodied arguer rather than a disembodied premise remains uncertain. The point remains however that there is a performance requiring the performer to say ‘I am’. If so, we can, it seems, cut down the most famous sentence in Western philosophy to one word: sum. This expression is something about which the ‘I’ in question can neither be mistaken nor be suspected of being mistaken. It remains perfectly acceptable for some third party to say of Descartes that ‘he is not’; but not for Descartes himself to say ‘I am not’.

Does cogito itself, therefore, contribute nothing to the power of the argument, given that the assertion ‘I am’ is as self-evidencing as, and delivers as much as (or as little as ), ‘I think’?

Admittedly, ‘I am’ is a thought: thinking is required for me to stand outside of myself to assert my existence. But it is not a thought that refers to itself as a thought. Nevertheless, while to say ‘I’ or ‘I am’ is to think, it is not necessary to spell this out reflexively by adding ‘I think’ – to assert that the I who is recognising their own existence is thinking. The role of thought – of thinking that ‘I am’ or that ‘I think’ – is not as an input to an inference that leads to the quasi-logical conclusion that the thinker exists. Rather, in both cases, its function is to make the thinker explicit to himself. The ‘I’ as it were speaks for itself rather than being arrived at as a conclusion. This is why it is present either side of ergo.

Most of the cogito argument therefore seems redundant. The work is done existentially, not inferentially. If you can say ‘I am’, then nothing more is needed to reassure yourself that you exist. But it doesn’t deliver much. The ‘I am’, that pops out at the end of Descartes’ argument is not the full Descartes. There is a mismatch between the flimsy episode of thought and the ‘I’ of the philosopher’s identity. Yes, it delivers something he cannot doubt, but that which is placed beyond the reach of doubt seems rather threadbare.

There are further questions. Given that the speech act may seem like a recipe for reassuring one’s self that one exists, what is its shelf life? Descartes himself admitted that it was no longer than the duration of the performance. What’s more, no-one else would – or should – be persuaded by his argument. Your thinking, or even saying, “I think, therefore I am” does not prove your existence to me. A figure in a dream I am having or a simulation could ‘perform’ the same ‘act’. Alexa could endlessly repeat the cogito without thereby proving that ‘she’ is an ‘I’ aware of, and asserting, ‘her’ own existence. So, what for Descartes is a proof, is for the rest of us merely the report of a proof that we must take on trust unless we do it ourselves. It works only for the person who performs it, and only while they are performing it.

Is it time, therefore, to bury Cogito, ergo sum? Absolutely not. Descartes’ journey from universal doubt to the reason he gives for placing a limit to doubt is the most electrifying example of that awakening out of ordinary wakefulness that is the beginning of true philosophy. As Edmund Husserl said in his Cartesian Meditations (1931), “anyone who seriously intends to become a philosopher must ‘once in his life’ withdraw into himself” and undertake the Cartesian journey that led to the cogito argument.

© Prof. Raymond Tallis 2024

Raymond Tallis’s latest book, Prague 22: A Philosopher Takes a Tram Through a City will be published in conjunction with Philosophy Now.