Whats is the actual motivation for necesity of renormalization group?

[crazzy__physicist]

Renormalization

[exchemist]

2 minutes ago, crazzy__physicist said:

Renormalization

Yeah, renormalisation. 👍  Cool. 

[joigus]

Normalisation should come first.

What is so suspicious about the motivation that you need an "actual motivation"?

Isn't the fact that physical parameters should be expected to depend on the length/energy scale at which you observe them enough motivation?

[MigL]

I don't know the mathematical motivation.
The Physical motivation is the elimination of divergences in the perturbative corrections of Quantum Field Theory.