Friday, February 18, 2011


Sometimes one wants a word like "un-negation" or "de-negation"—a word for the sentence "s" as it relates to "~s". For instance, when teaching logic, one wants to say that if one is asked to prove a negated sentence, one's best bet is often to prove a contradiction from that sentence's un-negation. I just found out that there is a handy word for this. It's "negand". Shiny! I never knew that. So one can say things like:
  1. Believing a negative proposition is the same as disbelieving its negand.
(I actually don't know if that's true, but one can say it.  But I am inclined to think it is true.)  There are also times when one wants to refer to a proposition and "a negation or negand of it".  I just love that word.

Last time I needed a word for this in class, I talked of "s" as the "de-negation" of "not-s", but "negand" is much better.


DL said...

Oh, I see! Operators takes operands, so negators takes negands. But then I don't think it's quite right to talk of the negand of a proposition; only of a negation. So, if r is ~s, then there is no "negand of r", but there is a negand of the "~" operation.

Alexander R Pruss said...

Right: only some propositions have negands, just as only some propositions have conjuncts.