[Undated]: Probability. Cogitations

The statement or belief that something is probable is related to prediction. Even when it appears to refer to the past, as in a statement that something probably happened, it means that at a future date it is likely that something will be discovered which proves that such-and-such event took place.

It has been supposed that there are universal hypotheses, so-called deterministic hypotheses, which state validly that 100% or 0% of things are A; and these are contrasted with statistical hypotheses, which state that a certain proportion of things, between 0% and 100%, are A (Braithwaite, Scientific Explanation, p. 115). Psychoanalytic hypotheses mostly belong to the latter class, which now includes the hypotheses of any scientific deductive system relating to quantum mechanics.

Braithwaite cites, by way of example, the statement: ‘51% of children born are boys.’ He points out that there can be two statements of probability involved thus: it is probable that the hypothesis – that it is probable that 51% of children born are boys – is true.

This at once raises the question whether any hypothesis says any more than that something is probable, unless it is a definitory hypothesis; even the universal hypothesis, unless it is definitory, only states (as I have already pointed out) that certain events are constantly conjoined. But this means that all hypotheses are really definitory hypotheses; that is, that in the view of the person using a particular s.d.s. (which for the time being expresses the view he holds) such-and-such phenomena are constantly conjoined.

What then does the rational number express? Does it express a fact that 51% of children born are boys, or that he wishes it to be understood by himself and others that he is in a state of mind in which he has a 51% feeling of certitude? If the latter, then he is also expressing the view that he is 51% liberated from the Ps position; or that 51% of the potentially unrelated facts (Poincaré, Science and Method, p. 30)

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