The excerpt I posted doesn't just say that the cogito sum is wrong, but rather explains *why* it is wrong. The potential strength of the assertion lies in its alleged "immediacy": that it cannot be doubted as true. But as Nietzsche explains, there are several hidden claims lying beneath the surface, such as the belief that an "I" exists in the first place, and that this "I" can correctly distinguish between thought and something like feeling or willing.
And doubting the cogito sum, unlike doubting logic (which Touka does), actually isn't circular. One can temporarily posit the existence of a self without needing to stake any metaphysical claims about it. Nothing is contradictory in saying "the self, as I understand it, is in part or in full illusory."
I'm not making a claim that I exist as anything other than a collection of thoughts, and if that collection does not exist I do not think. The statement is in essence tautological. And anyways, if "I think therefor I am" is false, then I certainly have nothing to do with truth on any level, so this conversation is absolutely and completely without merit.
Regardless of one's stance on the "value" of logical claims, or its place in some hierarchy, we can still know logical truths. According to your definition, we can learn about logic, making it relevant. We can also learn about poetry, making it relevant. And phenomenology. And music. And anything which fits within the framework of the human mind, for that matter.
'We' implies our own existence, which can only be confirmed through experiencing thought (well, according to you it doesn't, which means in essence we cannot know logical truths). And logic, poetry, music, etc. are relevant and I never claimed they were not. However, they are constructs and therefor a level removed from the base reality. The construct of god is relevance, however the reality of god is not (at least as defined).
It's quite a leap to come from "only things we can learn are relevant" to "only quantitative scientific inquiry is relevant."
It wasn't learn so much as detect directly or indirectly. And I never once claimed that only quantitative scientific inquiry is relevant, just that anything that is relevant that isn't a construct falls under the jurisdiction of the scientific method because of the way the scientific method is defined.
--
MMBN style fighting game made by me in the link below!
http://sandbox.yoyogames.com/games/184947-b8bn