There are two modes of justification.
- You have “already written the last line of your proof”, and you are looking for a reason to believe it. This is generally pretty bad. Like, it doesn’t increase your probability of arriving at a correct conclusion.
- You write “conjecture”, have some thoughts, and eventually write “theorem”, and then give a proof. This is more good. But still poke at it, please. Try to disprove it.