Article translated from English from J. Chastek's blog.

Proposition: If beliefs are proportioned to evidence, commitments are proportioned to evidence.

Commitments are either beliefs or have them as an essential principle.

Proposition: If commitments are proportioned to evidence, we cannot make vows or have in principle unbreakable commitments. Prudence also becomes impossible, along with everything that requires prudence: politics, virtue, happiness, etc.

No degree of evidence justifies an unbreakable future commitment, because we have almost no evidence about future states. Prudence requires commitments in the face of what is intrinsically uncertain, that is, non-evident.

Proposition: We must make vows, form commitments unbreakable in principle, and be prudent.

Human life requires principled and absolute commitments to, for example, spouses, nations, children, truth, God, religion, human progress, science, ideologies [like demands for "evidence"]. The need for prudence is per se nota.

Conclusion: We must not always proportion belief to evidence.