Modus Dolens, Way To Pain❢ Options

[Jon Awbrey]

There's a mode of inference that has become so popular in certain quarters that I decided it was time to fashion a suitable name for it. It goes a bit like this:

If A, then B.

Not B.

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But A simply has to be !!!

I know some scholars will quibble that it should be called “modus dolendo dolens” or something, but let's not be petty.

Jon Awbrey

[Text]

What does this mean?

If A has a value different from nothing then event B occurs. Then the opposite of event B occurs?

Since A only has to exist, and it always exists as a value, then B and its opposite always occur?

[Gruntled]

What does this mean?

If A has a value different from nothing then event B occurs. Then the opposite of event B occurs?

Since A only has to exist, and it always exists as a value, then B and its opposite always occur?

It means that if we can prove that:
* if A is true then B must be true
* B is false

then logically A must be false, yet some people persist in saying that A must be true.

For example, if John Smith lives in Des Moines, it follows that he lives in the USA. If we can prove that he doesn't live in the USA, he can't live in Des Moines. Yet there may be people who insist he does, maybe invoking WP:NOR.