If thoughts depend on memories and memories are unreliable then how can we trust any thought? I assume thoughts require memories because thoughts seem to require at least some time to compute, even with very simple thoughts we think thing one at a time - if it's not quite like that I think it's very close to something like that, maybe my whole doubt depends on a dubious connection between thought and memory, I don't know. I think the unreliability of memory is more obvious, memory seems to be something just given to us and we simply have to "trust" it but the possibility of doubt is still there. I recognize that there is some not inconsiderable paradox in doubting the very idea of being able to form a thought and using thought to achieve that doubt but alas... I wonder if this suggests that thought in its truest form is something more intuitive and directly related to a grasp of the present moment than reason as it is generally understand as a discursive process.