Starting a company is to live in a contradiction:
1. You have to maintain the irrational belief that you will prevail, even in the dark moments when everyone tells you that you will fail.
2. But at the same time, you have to confront the facts of your reality, however brutal they may be.
This is the psychological duality that you are forced to inhabit.
But it's not actually a contradiction.
The odds may seem against you. But odds are averages over things in the past. As a founder, you are—by definition—building something new. It is your job to build conviction on a plan that turns the odds around.
And often, the mere existence of your "irrational belief" is enough to do that. You may be the first person to be irrational enough to give your plan a real shot.
There are times when faith in a fact can help create that fact. A great founder has the judgement to know when that's true.