An assumption is still considered "new" information. It's something the author has implicitly used to draw the conclusion, but since it's not an explicit part of the argument, it can still be considered "new".

imhimanshu -

Let me echo what Bill has said and elaborate a little...In order to "strengthen" or "support" a conclusion you must provide new information. You cannot strengthen something by stating what has already been said. For example, if I had just pasted your post from above and said nothing else I could not strengthen this discussion because I would not have added something new.

Bottom line: In order to strengthen or weaken a conclusion you must provide "new" information.

Now what form does this take? The new information does not have to be - and in fact should not be - unexpected completely surprising information. Instead it should work with the parts of the argument that are already in the stimulus. You see what you are really doing when you strengthen an argument is by making the evidence better linked to the conclusion.

One way to anticipate the correct answer is to look for the "step" that the argument has skipped over. This can be referred to as an assumption. For example if I say that "All humans are warm-blooded. Therefore, John is warm-blooded." You can see my assumption quite clearly, I assume that "John is human." If that were stated in an answer choice it would be the correct answer. If we do not know that then for all we know John is a robot, and then the evidence does not lead to the the conclusion.

Here is an article that I wrote last year that can help you understand what we mean at Veritas when we talk about strengthening! https://www.beatthegmat.com/mba/2011/02/ ... duncan-way

Good luck!