Suppressed Evidence

Intentionally failing to use information suspected of being relevant and significant is committing the fallacy of suppressed evidence. This fallacy usually occurs when the information counts against one's own conclusion. Perhaps the arguer is not mentioning that experts have recently objected to one of his premises. The fallacy is a kind of fallacy of Selective Attention.

Example:

Buying the Cray Mac 11 computer for our company was the right thing to do. It meets our company's needs; it runs the programs we want it to run; it will be delivered quickly; and it costs much less than what we had budgeted.

This appears to be a good argument, but you'd change your assessment of the argument if you learned the speaker has intentionally suppressed the relevant evidence that the company's Cray Mac 11 was purchased from his brother-in-law at a 30 percent higher price than it could have been purchased elsewhere, and if you learned that a recent unbiased analysis of ten comparable computers placed the Cray Mac 11 near the bottom of the list. If the relevant information is not intentionally suppressed by rather inadvertently overlooked, the fallacy of suppressed evidence also is said to occur, although the fallacy's name is misleading in this case. The fallacy is also called the Fallacy of Incomplete Evidence and Cherry-Picking the Evidence. See also Slanting.

Sharpshooter's

The sharpshooter's fallacy gets its name from someone shooting a rifle at the side of the barn and then going over and drawing a target and bulls eye concentrically around the bullet hole. The fallacy is caused by overemphasizing random results or making selective use of coincidence. See the Fallacy of Selective Attention.

Example:

Psychic Sarah makes twenty-six predictions about what will happen next year. When one, but only one, of the predictions comes true, she says, "Aha! I can see into the future."

Selective Attention

Improperly focusing attention on certain things and ignoring others.

Example:

Father: Justine, how was your school day today? Another C on the history test like last time?
Justine: Dad, I got an A- on my history test today. Isn't that great? Only one student got an A.
Father: I see you weren't the one with the A. And what about the math quiz?
Justine: I think I did OK, better than last time.
Father: If you really did well, you'd be sure. What I'm sure of is that today was a pretty bad day for you.

The pessimist who pays attention to all the bad news and ignores the good news thereby commits the fallacy of selective attention. The remedy for this fallacy is to pay attention to all the relevant evidence. The most common examples of selective attention are the fallacy of Suppressed Evidence and the fallacy of Confirmation Bias. See also the Sharpshooter's Fallacy.

Confirmation Bias

The tendency to look only for evidence in favor of one's controversial hypothesis and not to look for disconfirming evidence, or to pay insufficient attention to it. This is the most common kind of Fallacy of Selective Attention.

Example:

She loves me, and there are so many ways that she has shown it. When we signed the divorce papers in her lawyer's office, she wore my favorite color. When she slapped me at the bar and called me a "handsome pig," she used the word "handsome" when she didn't have to. When I called her and she said never to call her again, she first asked me how I was doing and whether my life had changed. When I suggested that we should have children in order to keep our marriage together, she laughed. If she can laugh with me, if she wants to know how I am doing and whether my life has changed, and if she calls me "handsome" and wears my favorite color on special occasions, then I know she really loves me.

Committing the fallacy of confirmation bias is often a sign that one has adopted some belief dogmatically and isn't seriously setting about to confirm or disconfirm the belief.