Your own thumb on the scale

Where reasoning quietly bends.

Confirmation bias

We search for, notice and remember what fits what we already think. The practical fix is to look actively for the best case against your position and to write it down.

Ask what you would say if the same evidence supported the other side.
Deciding what evidence would change your mind before looking is the strongest defence.

Motivated reasoning

When a conclusion is comfortable, we accept weak evidence; when it is uncomfortable, we demand strong evidence. Noticing the asymmetry in yourself is most of the skill.