It is said that whole of electromagnetism can be completely described by the Maxwell's equations.
The thing that intrigues me is that how does superposition principle follow? First, I take an example, where $2$ charges $q_i$ are placed at a distance $d_i$ from a point, $i=1,2$. Now to calculate the field at that at point, we simply add the electric field due to individual charges at that point if the other charge was not there (Field calculated using Gauss' law). But how do we know that now, after the charges are placed together, the electric field due to both of them there is unaffected and also, that it adds up?
Edit: For all those who are saying that since Gauss' Law is a linear equation, that is why the SP follows. Please read the question again. I am asking the reasoning behind it, why SP follows from linearity (Or how).
It would be appreciated if someone explains it in the simple example I chose above. (2 point charges)