Melville understood it well:

If I had been downright honest with myself, I would have seen very plainly in my heart that I did but half fancy being committed this way to so long a voyage, without once laying my eyes on the man who was to be the absolute dictator of it, so soon as the ship sailed out upon the open sea. But when a man suspects any wrong, it sometimes happens that if he be already involved in the matter, he insensibly strives to cover up his suspicions even from himself.