Authentic Science Fiction Monthly No. 46 — page 99: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

eae Inference by FRANK WILSON, B.Sc. LOGIC IS FUN—2 ig this second article in this series, we are going to see what one can infer from given propositions—but first, let’s look at the homework we gave you for last month. Did you do it? It doesn’t matter very much if you didn’t. Anyway, for those who did, here are the answers: 1, Universal affirmative; 2, Singular universal affirmative; 3, Implicative or disjunctive; 4, Alternative; 5, Conjunctive. Now we can go ahead with inference. There are two forms at least of this—immediate inference and mediate inference. Broadly, the difference is that in the first, you infer something from one proposition; and in the second case, you infer | something from two propositions. We’ll deal with immediate inference first. To begin with, the four classical categorical propositions that we dealt with last month fall into their own little set of inferential relationships. You will remember that the four propositions are as follow (the symbolic form is shown in brackets): All S is P (SaP), No S is P (SeP), Some Sis P (SiP), Some S is not P (SoP), where S stands for the subject and P for the predicate. Now given the truth or falsity of any one of these propositions, you can determine the truth or falsity of most of the others. Sometimes you just cannot tell. The following table shows you what you can infer and what you cannot: ts Given that it can be inferred that SaP is true SeP is false, SiP is true, SoP is false. SaP is false SeP is ?, SiP is ?, SoP is true. SeP is true SaP is false, SiP is false, SoP is true. SeP is false SaP is ?, SiP is true, SoP is ? SiP is true SaP is ?, SeP is false, SoP is ? SiP is false SaP is false, SeP is true, SoP is true. SoP is true SaP is false, SeP is ?, SiP is ? SoP is false SaP is true, SeP is false, SiP is true. 98 Ccomiclbooks.cotin-