There are many LSAT questions that involve causal reasoning, which is significantly different from the conditional reasoning that makes up most of the rest of the test. PowerScore’s Logical Reasoning Bible squeezes in a chapter on causal reasoning between the chapter on “weakening arguments” and “strengthening arguments.” There’s a reason for that–a statement which might a perfectly valid conditional statement (“if the rooster crows, then the sun comes up”) could be a ridiculous causal claim (“the rooster crows, which causes the sun to come up”).
PowerScore identifies five situations which weaken a causal relationship. I have taken the liberty of turning them into an acronym:
- R: Reverse causation
- A: Alternate cause
- C: Cause without effect
- E: Effect without cause
- S: Statistical errors
Let’s run through these, using our rooster example. Perhaps the rooster does not cause the sun to come up–instead, it is the early morning sunlight that causes the rooster to crow. That would be a clear case of reverse causation.
The problem with that explanation, as any chicken keeper knows, is that roosters start crowing long before the sky begins to get light. Maybe there is some kind of biological clock inside the rooster that tells it that 24 hours have passed. If so, that would be an alternate cause–something other than the sun itself that causes the effect.
If we wanted to prove that the rooster doesn’t really make the sun come up, we just need to get the rooster to crow in the middle of the night and see what happens. This happens to me now and then when we start something time consuming right around sunset. I have to grab my flashlight and go close up the chickens late at night. My roosters start crowing their heads off when I turn on the lights, and the sun stays put. It’s hard to have a causal relationship if you you can have the “cause” (the rooster crowing) without the “effect” (the sun coming up). That’s a cause without effect situation.
Most of my students don’t even keep chickens–which means the sun comes up on them even though no rooster crowed. That is an effect without cause situation.
PowerScore’s final category involves statistics. When we say, “The rooster crows and the sun comes up,” we oversimplify the situation. My roosters crow pretty much all day long. (That’s why we keep them well away from the house!) If we graphed all the times each rooster crows and plotted it against the sunrise, it would be obvious that the rooster has nothing to do with the sunrise. The reason I associate sunrise with roosters is that when those noisy birds wake me up I want to go make rooster soup! If I’m already awake, I just ignore their crowing. If I had good data instead of my very selective memory, I would never associate crowing with sunrise.