We see that a vast net of family likenesses connects the cases in which the expressions of possibility, “can”, “to be able to”, etc. are used. Certain characteristic features, we may say, appear in these cases in different combinations: there is, e.g., the element of conjecture (that something will behave
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in a certain way in the future); the description of the state of something (as a condition for its behaving in a certain way in the future); the account of certain tests someone or something has passed. ‒ ‒