There are two ways of answering such questions, I mean the deductive way and inductive way. Mortality of man is established by either of the above ways. In deductive way we take it for granted from reliable source, "Man is Mortal." But in the inductive way we approach the same truth by our poor reasoning of "observation and experiment." By observation we can see that Gandhi dies, Fotilal dies, C.R. Das dies, Patel dies and therefore we conclude that man dies or, "Man is Mortal". Then again in the same deductive way when we reason that man is mortal, and find that Jawaharlal is a man and thus conclude that Jawaharlal is mortal.