#26- Before 1986 physicists believed they could describe the

[Jonathan Evans]

Hi, CJ12345!

Strengthen answers exist on a spectrum. If we are in agreement that answer choice (B) could help link the premises to the conclusion, then that's enough.

If no previous results are incompatible with a 5th force, then we have made it incrementally more likely that a 5th force might exist. This ipso facto supports the conclusion, as articulated in the question stem, that "there is a 5th force."

In your question, you negated answer choice (B). This approach is not applicable to strengthen questions. It only works on assumption questions. You are correct that even if previous scientific results are incompatible with a 5th force, it still could be possible that there is a 5th force. That's okay. The negation of correct strengthen answer choices need not invalidate the conclusion. However, one might note that the statement in answer choice (B) when negated does weaken the conclusion.

I hope this helps!

[Cflores17]

Hopefully this post helps someone on this problem.

so (B) says "NO Previously established scientific results are INCOMPATIBLE...with a fifth universal force"

This is Convoluted camouflage by using two negative terms.

So if you take out the negatives you get "Previously established scientific results are compatible with a 5th.."

Based on the C/E techniques in the book for strengthening. I would say that this is easily
"... eliminate possible problems with the data (A casual reasoning strategy given in the powerscore book to confirm if the answer strenghtens the argument)

[Robert Carroll]

Cflores17,

I think that's a good point. I also think Nikki's post above explains well that, while an absence of counterevidence doesn't prove that something is true (and, indeed, thinking otherwise is a standard flaw on the LSAT), an absence of counterevidence does strengthen an argument in general. That is what answer choice (B) accomplishes - nothing we know so far excludes the possibility of a fifth force. One reason I want to be explicit about that is because it's good to know that this way of strengthening arguments goes beyond just causal arguments and can potentially be used more widely than just those.

Robert Carroll