I was watching this documentary on Netflix called Shadow of Truth that goes through a murder case and an alleged false confession that follows. There are some quotes in there that I think are worth keeping in here.
If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.
René Descartes
Nothing is easier than self-deceit.
For what every man wishes,
that he also believes to be true.Demosthenes
Where doubt is, there truth is - it is her shadow.
Ambrose Bierce