It's known that Descartes was someone who believed in a God but isn't the contrapositive of "I think therefore I am" an atheistic notion. That is -I am not therefore I do not think- meaning if one does not exist then one cannot be conscious which points at no consciousness after death or no after life.

I know this can be resolved if we consider existence of the mind to be eternal but Descartes never talks about that (the mind being eternal specifically) in 'Discourse on the Method' and since he begins by using a mathematical logic to build his argument how does he resolve this? If he does.

  • I suppose mind is different to the soul, and religious thought believe in the eternity (until the judgment) of the soul.
    – John Am
    Oct 23, 2015 at 16:05
  • 1
    It seems that one who says to one's self "I don't think, therefore I am not" is already thinking (and therefore existing). Oct 23, 2015 at 18:06
  • Turning a thought upside down can be useful thinking tactic, but one has to be sure that there remains some content there - it rarely works without taking in the full context. Oct 23, 2015 at 19:34
  • When someone speculates that when dead "he will not think therefore he will not exist " does not implies thinking after death. The poster is right. The contraposition of the famous quote can be considered as an atheist notion.
    – John Am
    Oct 24, 2015 at 15:37
  • if I think not am I not? I think not!
    – user48165
    Aug 31, 2020 at 20:47

2 Answers 2


Aren't you confusing "existence" with "finite bodily existence" or "alive" in a modern materialist sense? Descartes has already abstracted away all his bodily senses before arriving at this essential point. Res cogitans also "exists" and is prior to res extensa.

Existence and consciousness alike (our own or those of God and the Angels) are not confined to this mortal coil. Indeed, "mind" is an immaterial substance only hinged to material existence via, Descartes hypothesized, the pineal gland. As to your contrapositive, Kant argued that "existence" is not a proper predicate, which is partly why the ergo sum is not valid.


The contrapositive:

I am not therefore I am not thinking

Is confusing at one level, when we take into accounts Parmenidian position on non-being; when something is not we can't then ascribe properties to it; for there is no bearer for those properties - nothing in which those properties can inhere; so it's an incoherent proposition; so we can neither say that it is true or false, since truth-values can only be ascribed to coherent propositions.

This shows that simply because a proposition is coherent doesn't mean that it's contrapositive is; it is well-formed at the formal level; but not when must, as is here, consider the Sinn (Sense) of the proposition.

One might also consider turning the proposition around:

I am therefore I think

This suggests that thinking is an essential part of being, when that being is subjectivity - and this is signified by the use of the pronoun 'I'; for a stone or a box does not say 'I'.

So though this isn't the contrapositive, it does retain coherence ie sense.

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