When is certainty justifiable?

Karl Popper would say that certainty is never justifiable. But there is a worthwhile line of thought in Wittgenstein, to the effect that some doubts would make your whole intellectual world fall apart. Broadening the theme to certainty about ethical and political matters, and the question of justification for rigid rules. We can also look at the tension in the fact that many people would argue against certainty in having a religious faith, but would be quite happy to be certain in their atheism.

Richard Baron is a philosopher living in London.
He is the author of Projects and Values and Deliberation and Reason.
He has published articles in Philosophy Now and in Ethical Record.
He has also had a career as an adviser on tax policy, both for the British Government and for the Institute of Directors.