Flimflam inoculation 2: Appeal to consequences

(OK, so number 3 came before number 2)

Ever heard this dull-witted line of reasoning?

Hitler believed in evolution.

Therefore, evolution is not true.

Or how about this one?

Christians all around the world are helping those in need.

Therefore, Christianity must be true.

Even if Hitler DID believe in evolution (I doubt he even understood it), the fact that he was a douche-bag doesn't say anything about the truthfulness of evolution. And while it's terrific that people help each other, the simple fact that many people agree on something does not make it true. Most people used to think the world was round.

The "appeal to consequences" logical fallacy often takes one of these forms:

If X, then Y.

I really like Y.

So X is true.

Or...

If X, then Y.

I really don't like Y.

So X is false.

Neither of those conclusions follow logically. But the like or dislike of "Y" can be very compelling and distracting.

[From intelligent-falling.blogspot.com]