bleechers's Blog

Kids These Days

My kids and their friends like to use the phrase "that was so random" when someone says something that does not follow the current line of thought. Let's say the group is talking about school (this is hypothetical after all) and one in the group blurts out "I'd like some ice cream," the comment is met with "that was so random!"

But was it "random?"

Actually, no, it was a "Non sequitur." The thought was very much chosen by the speaker and had a defined intent. Had the kid just blurted out the words "ice cream" for no reason, then you might say "that was random."

A "Non sequitur" is something that does not follow. You can equate it with the idea "out of sequence." In logic it can be used of a conclusion that does not follow a premise.

Premise: All basketballs are round.
Premise: Bob's ball is a basketball.
Conclusion: Bob's ball must be round.

That conclusion follows the premises.

Premise: All basketballs are round.
Premise: Bob's ball is a basketball.
Conclusion: Bob's a good dancer.

A "non sequitur" conclusion would be like the one above or even "Bob's house is round." The first is more absurd, but neither follows the argument.

While we're there, you can have a conclusion which does follow the premise, but that doesn't necessarily mean that the conclusion is correct

Premise: All cheese is from the moon.
Premise: Bob has some cheese.
Conclusion: Bob's cheese is from the moon.

The conclusion follows the argument, but it is based on a faulty premise. Even if you get a correct conclusion (based on a premise), that doesn't mean that the whole argument is sound

Premise: All cheese is from Wisconsin.
Premise: Bob has a piece of cheese.
Conclusion: Bob's cheese is from Wisconsin.

The conclusion follows the argument and Bob's cheese may very well be from Wisconsin, but that does not make the premise sound. We cannot point to the conclusion being correct to argue that the premise is sound. In both of the last two examples we have faulty premises, one just happens to lead to a correct conclusion (purely by happenstance).

Lastly, we can have an unsure premise and come to conclusions that cannot be verified.

Premise: The girl who lives in that room is pretty.
Premise: Bob likes pretty girls.
Conclusion: Bob would like the girl in that room.

Well, unless we've established that the girl is indeed pretty, we cannot say whether any of this is correct. It look correct. It sounds correct. We may have to trust somebody's opinion on the first premise. But we cannot draw hard and fast conclusions based on conjecture or pure opinion. And even in Bob's case, how do we know he likes pretty girls?

Sometimes "consensus" can make for a relatively sound argument. Sometimes "preponderance of evidence" can lead to relatively sound conclusion. But these are beyond either pure opinion or pure conjecture.

Premise: Michael Jordan was a great basketball player.
Premise: Bob enjoys watching good basketball.
Conclusion: Bob would enjoy watching Michael Jordan

Not absolute, but we can safely say that if Bob does indeed like basketball, he would enjoy watching Jordan. We cannot be 100% certain of our conclusion, but it is an educated conclusion based on a "consensus" of basketball fans, analysts and players.

Civil trials are based on evidence. A judge or a jury must draw conclusions based on the evidence (premises) presented. In these cases, all we can do is examine the evidence that is available to us and make the least prejudiced decision that we can.

I hope that wasn't too "random."