Necessity is the mother of invention. This is a phrase which is used fairly often, and which most people seem to accept as common sense. But is necessity really the mother of invention? When are things invented out of necessity? Oh sure, every once in a while someone will invent something to solve some personal problem of theirs, but most of the time profitability is the mother of invention. Sure, necessity might be an ancestor to invention, perhaps two, three generations back, but the direct bearer of invention is profitability. Surely, down the line necessity is an important factor, considering that most things wouldn't be profitable, if it weren't necessary, but the most accurate expression of invention's lineage is "profitability is the mother of invention."