Authentic Science Fiction Monthly No. 46 — page 101: what you’re looking at

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

AUTHENTIC SCIENCE FICTION not teaching you logic and, therefore, will not be giving you the rules for eduction, you'll just have to take my word for it that it cannot be done. (Anyone who wants the rules should write to me, care of the Editor, and I will send them.) Let us just take a look at conversion using a real proposition. We can start off with the proposition “‘All planets have mass.” _ This converts to ““Some bodies with mass are planets.” If we had started with ‘“‘No. planets have mass,’”’ we would have converted to “‘No bodies with mass are planets,’ which, although demonstrably untrue is nevertheless logical. Deduc- tive logic does not help you to discover whether your original propositions are true or false. It simply enables you to say what follows from them if they are true. Finding true proposi- tions is the concern of induction and is no easy matter, whereas deduction—finding what follows from true propositions—is relatively simple. Inference is a part of deduction. That was a side-track. Let us go back to immediate inference. The proposition “‘Some planets have mass” converts to ‘‘Some bodies with mass are planets,” and the proposition “Some planets do not have mass” cannot be converted. So much for conversion. Another process of eduction is making the original propo- sition state a relationship between S and non-P. This is called obversion. The obverse of ‘‘All planets have mass’? is “No planets are massless bodies” (the actual words used, you will see, are not very important; it is the meaning that matters). ““No planets have mass’”’ obverts to ‘‘All planets are massless bodies,” “Some planets have mass’’ obverts to ‘“‘Some planets are not massless bodies,”’ and “‘Some planets do not have mass”’ obverts to “Some planets are massless.” Putting all this into shorthand, it becomes: SaP obverts to SeP; SeP obverts to SaP; SiP obverts to SoP; and SoP obverts to SiP. (You will remem- ber that a - over a letter means non-.) So, from our original proposition we have seen how to 100 comicloooks. com