Blaming Being Illogical's Not Always Sensible

"You're being illogical"
"Your argument is illogical"
"My argument is completely logical"

Logic, or a lack thereof, seems to the standard mark of evidence held up for or against an argument. So, it supposedly goes: an argument is invalidated by being illogical, validated by being logical. If someone is drawing an invalid conclusion or presenting an invalid argument, it's because there is a fault in their logic. This explanation, I want to argue, doesn't always make sense.

Logic can certainly take the blame in some situations. For example, a person may take p to be true and ultimately know that if p is true then q must also be true, but still deny that q is true. Or they may beg the question, by assuming the conclusion they're trying to justify. But frequently, mistakes can't be blamed on logic.

Perceptual problems and inaccurate knowledge can be at fault. I won't talk much about the former here, but will note that Edward de Bono has (see his book "I am Right, You are Wrong"). Logical rules such as "if x then y" (e.g. "if the afternoon sky is red then the weather will be fine in the next day") represent knowledge about the world. They say that the world is such that a red sky in the afternoon is an indicator that the weather will be fine the next day. "if x then y" is an encoding of knowledge.

Flawless logic can lead to mistakes, if the knowledge encoded by statements such as "if x then y" is inaccurate. While it may seem obvious that flawed knowledge can lead to mistaken conclusions, this reason seems frequently overlooked. Someone may be accused of overlooking a simple fact, but in cases where there's a more subtle problem with their knowledge of how the world works and is, their mistake is far more likely to be attributed to being illogical.

This actually takes us back to the issue of perception. I'm sure we've all experienced situations where a conclusion seems obvious to us, but not matter many times we enumerate the facts and outline the chain of reasoning, the other person just don't gettit. The conclusion that's usually drawn is that the person is "illogical", as if there's some problem with their logic.

Illogical they may be, but more frequently, I think, they just have different knowledge of the world. The other person's logic may be impeccable, but they may have quite different knowledge -- quite a different view of the way it is and works -- giving them no reason to accept your conclusions and leading them to different ones. They're perceiving the situation differently. Thus, effectively criticising their view would require criticism of their underlying beliefs (knowledge) about the world.

It would be useful to investigate the frequency of the various causes of mistakes in reasoning. The conclusion that I've drawn from my experience is that perceptual and knowledge problems are far more common than logical problems, but this is something for systematic investigation to determine (it may have already done so!).

What I can say is that when we see that statements like "if x then y" are primarily encodings of knowledge, it's easier for us to see that any long chain or reasoning is primarily composed of knowledge, and thus that if we're looking for the causes behind mistaken conclusions, knowledge should be a big potential candidate.