1.  A living option is one in which both hypotheses are live ones.  If I say to you, “Be a theosophist or be a Mohammedan,” it is probably a dead option, because for you neither hypothesis is likely to be alive.  But if I say, “Be an agnostic or be a Christian,” it is otherwise:  trained as you are, each hypothesis makes some appeal, however small, to your belief.

2.  Next, if I say to you, “Choose between going out with your umbrella or without it,” I do not offer you a genuine option, for it is not forced.  You can easily avoid it by not going out at all.  Similarly, if I say:  “Either love me or hate me,” “Either call my theory true or call it false,” your option is avoidable.  You may remain indifferent to me, neither loving nor hating, and you may decline to offer any judgment as to my theory.  But if I say, “Either accept this truth or go without it,” I put you on a forced option, for there is no standing place outside of the alternative.  Every dilemma based on a complete logical disjunction, with no possibility of not choosing, is an option of this forced kind.

3.  Finally, if I were Dr. Nansen and proposed to you to join my North Pole expedition, your option would be momentous; for this would probably be your only similar opportunity, and your choice now would either exclude you from the North Pole sort of immortality altogether or put at least the chance of it into your hands.  He who refuses to embrace a unique opportunity loses the prize as surely as if he tried and failed. Per contra the option is trivial when the opportunity is not unique, when the stake is insignificant, or when the decision is reversible if it later prove unwise.  Such trivial options abound in the scientific life.  A chemist finds an hypothesis live enough to spend a year in its verification:  he believes in it to that extent.  But if his experiments prove inconclusive either way, he is quit for his loss of time, no vital harm being done.

It will facilitate our discussion if we keep all these distinctions well in mind.[55]

In some arguments the working out of the definitions of a few principal terms may occupy much space.  Matthew Arnold, a famous critic of the last generation, wrote as an introduction to a volume of selections from Wordsworth’s poems an essay with the thesis that Wordsworth is, after Shakespeare and Milton, the greatest poet who has written in English; and to establish his point he laid down the definition that “poetry is at bottom a criticism of life; that the greatness of a poet lies in his powerful and beautiful application of ideas to life—­to the question, How to live.”  To the development of this definition he gave several pages, for the success of his main argument lay in inducing his readers to accept it.