Should black box or white box testing be the emphasis for testers?

Question

Which type of testing would you say should be the emphasis (for testers/QAs), and why?

A quick set of definitions from wikipedia:

Black box testing

Answer 1

What constitutes, "internal knowledge?" Does knowing that such-and-such algorithm was used to solve a problem qualify or does the tester have to see every line of code for it to be "internal?"

I think in any test case, there should be expected results given by the specification used and not determined by how the tester decides to interpret the specification as this can lead to issues where each thinks they are right and blaming the other for the problem.