# Math Help - About 'first principles'

I don' t understand why we called the process of finding a derivative from the definition 'finding the derivative from first principles'.
Why we have 's' after "principle"?

2. Originally Posted by ling_c_0202
I don' t understand why we called the process of finding a derivative from the definition 'finding the derivative from first principles'.
Why we have 's' after "principle"?
Because there is not a single principle that we start from but a number of
them.

RonL