Comments on: A nearly ubiquitous form of fallacious reasoning

By: A=B implies that 1=1, therefore… « 360

A=B implies that 1=1, therefore… « 360 — Wed, 03 Feb 2010 01:08:00 +0000

[...] implies that 1=1, therefore… By TwoPi I’ve ranted in the past about the fallacy of trying to prove an identity by starting with the equation itself, then [...]

By: infinity

infinity — Wed, 05 Mar 2008 03:48:49 +0000

I always hated seeing this correction on my homeworks/tests, but understood why it was there and when I was grading the other day, I wrote this correction down. It’s almost like you turn into your professors just like you turn into your parents…

By: Ξ

Tue, 04 Mar 2008 09:39:15 +0000

I’m not sure that the answer is to completely avoid it, but rather to emphasize the “if and only if” nature of the argument within the proof. (Although I admit, even though I talk about that necessity to all my classes and take off points if it’s left off, only about one such proof in fifteen “proofs” of this nature actually uses “if and only if” or explicitly points out that each step is reversible. It really is ingrained in many students that this type of argument is just fine as is.)

By: Batman

Batman — Tue, 04 Mar 2008 02:10:45 +0000

Or, as one of my professors put it, “It is good to be clever, but better to be correct.”