DISTRIBUTION OF TERMS. In logic a term is said to be distributed in a proposition when explicit reference is made to its whole extent or extension. Otherwise (that is, not only when reference is made explicitly to a part only of the extension of the term, but when explicit reference is simply not made to its whole extension) it is said to be undistributed. Thus, in a proposition of the form No S is P both the subject and the predicate are dis tributed. In the form Some S is P, neither S nor P is distributed. In All S is P, S is distributed, but P is not. Lastly, in Some S is not P, S is not distributed, but P is. Briefly, only universal propositions distribute the subject term (S), and only negative propositions distribute their predicate (P). Naturally, singular terms (including proper names used as singular terms) are always distributed, for they only refer to one object, and cannot refer to less. The importance of the distribution of terms arises from the fact that it is a principle of formal inference that no term may be distributed in this conclusion unless it was distributed in the premises. That is why, e.g., All S is P can only be converted into Some P is S (not into All P is S), and Some S is not P cannot be converted at all.