With the following code

void TestF(const double ** testv){;}
void callTest(){
    double** test;
    TestF(test);
}

I get this:

error C2664: 'TestF' : cannot convert parameter 1 from 'double **' to 'const double **'

I cannot understand why. Why test cannot be silently casted to const double**? Why should I do it explicitly? I know that

TestF(const_cast<const double**>(test)) 

makes my code correct, but I feel this should be unnecessary.

Are there some key concepts about const that I'm missing?