I clear doubt from every single cell in my body.

Doubt is felt in specific places, which is the strange part of it. The throat narrows. Something drops in the stomach before you press send. The jaw gets involved. For a state of mind it is remarkably physical, and it arrives in the body before the argument for it has finished forming.

Which means it can sometimes be answered there too. Not by reasoning with it — reasoning is slow and doubt is fast — but by unclenching the hands, straightening up, breathing out for longer than you breathed in. The body loses conviction quickly, and the thoughts follow it more often than the other way round.