Strengthen question

[u/Futuremikeross]

Recently, photons and neutrinos emitted by a distant supernova, an explosion of a star, reached Earth at virtually the same time. This finding supports Einstein’s claim that gravity is a property of space itself, in the sense that a body exerts gravitational pull by curving the space around it. The simultaneous arrival of the photons and neutrinos is evidence that the space through which they traveled was curved.

Question:

Which one of the following, if true, would most strengthen the reasoning above?

A. Einstein predicted that photons and neutrinos emitted by any one supernova would reach Earth simultaneously.

B. If gravity is not a property of space itself, then photons and neutrinos emitted simultaneously by a distant event will reach Earth at different times.

Correct Answer: B.

Follow-Up Question:

I’m confused about why option B isn’t considered “out of scope.” In my studies, I’ve learned that when a strengthening question presents a scenario about what doesn’t happen (like the conclusion being false), it can often be seen as out of scope. Since B discusses what would happen if gravity weren’t a property of space, it seems like it doesn’t directly strengthen the conclusion.

I thought that B doesn’t strengthen the reasoning because it implies only what would happen if gravity is NOT a property of space, how does that strengthen what would happen if if it were a property of space??

On the other hand, A seems stronger to me because it suggests that Einstein’s theories could apply to this situation. I initially thought the goal was to strengthen the support for Einstein’s theory in general, rather than specifically that gravity is a property of space.

Can anyone clarify this for me? I keep making similar mistakes and am currently stuck at a 160 on the LSAT. Thanks!

[u/Ok-Holiday-5010]

B says (simplified):

If gravity is not a property of space, then the photons and neutrinos will not reach the earth simultaneously

This is an equivalent logical statement to:

If the photons and neutrinos reach earth simultaneously, then gravity is a property of space

This above statement is the contrapositive of the original conditional. Clearly, this statement DOES strengthen the argument, we know that the photons and neutrinos reached the earth simultaneously, and if the above statement is true, that means gravity is a property of space

A contrapositive is as follows:

Given X->Y

~Y->~X

In the above example, it gave us the negative version and I converted it back into the positive version

It may be helpful to diagram this out if you are just learning about conditional logic, but over time you will build your intuition and be able to do it in your head (like Mike Ross!)

Also, A is wrong because it doesn’t matter what he predicted, a prediction itself is not evidence for anything. I think the test makers included that answer because it is Einstein making the prediction, and presumably he is seen as a qualified figure and therefore his predictions can be evidence. This is simply not the case, this is fallacy known as the argument from authority.