The weight of Manhattan

Today, my manager was reading online about absurd questions that have been known to be asked at job interviews, and he came with one that he found particularly tricky: "What is the weight of Manhattan?" He had the answer on his screen and asked us what we thought. I gave him the right answer immediately, which flabbergasted him. The answer is below, I will let you think about the question and see if you can get it without reading further. My second paragraph has clues that will help you.

I didn't know the answer, I had not read it on the internet before (as my manager suspected at first), however I knew how to deduce it. You know how to do it? If you are a bit familiar with René Magritte, it should come to you easily. In my case, I immediately remembered my course of linguistics in cégep and Ferdinand de Saussure. If you have been reading this far, you have enough clues to find out. And you know that the answer is not found through geology, physics or mathematics. Have you given up yet? Found it? Well, here it is: Manhattan has no weight. See, Manhattan is a word and thus is weightless. Simple linguistic: a sign has no relationship other than an arbitrary one to the concept it represents. Words have no weight, size, form or existence in themselves. I have to say, I am quite proud of myself.