What is 'necessity is the mother of invention' all about?

Answer 1

I adjusted your question to give the exact wording of the saying.

Think about it for a minute - if you need to do something and the proper tool or technique doesn't exist, it's basic human nature to try to figure out a way to solve the problem. For example, back a couple of million years ago, Ugg and Glugg were picking up stones to break open nuts and animal bones to eat. But that's pretty uncomfortable and doesn't give you a lot of power, so loads of reasonably good hunted & gathered food would go to waste. After a lot of frustration, someone figured out that if you attached the stone to a stick, you'd (a) spare your hand (paw??) a lot of discomfort, as well as (b) have more power to crack open larger food sources. Presto, the hammer is born!