Rescher, 83 (Nicholas, Department of Philosophy at the University of Pittsburgh, Risk: A Philosophical Introduction to the theory of risk evaluation, p. 67)
In such situations we are dealing with hazards that are just not in the same league. Certain hazards are simply unacceptable because they involve a relatively unacceptable threat—things may go wrong so badly that, relative to the alternatives, it’s just not worthwhile to “run the risk,” even in the face of a favorable balance of probabilities. The rational man is not willing to trade off against one another by juggling probabilities such outcomes as the loss of one hair and the loss of his health or his freedom. The imbalance or disparity between risks is just too great to be restored by probablistic readjustments. They are (probablistically) incommersuable: confronted with such “incomparable” hazards, we do not bother to weigh this “balance of probabilities” at all, but simply dismiss one alternative as involving risks that are, in the circumstances, “unacceptable”.