Probability

When it comes to action, we can never wait until we have an absolutely certain understanding of the entire situation. We only take the path down which we are lead by probability. Every "duty" must follow this path; for this is how we sow, sail, make war, get married, and have children. In all these things, the result is uncertain, but we nevertheless decide to undertake those actions which we think have some hope of succeeding..... We go where reason- and not absolute truth- leads us.

- Seneca, On Benefits