anything that can't be proven to be wrong should be treated as "unknown".From this aspect agnostics are right.
nope, scientists make cases, and try to prove, or prove the opposite, i happen to know it as a scientist.

Anything that can be proven, but we aren't able to at the moment (due to technological reasons) should be considered unknown. But things that can never be proven, like the existence of a deity or deities, should not be considered fact because it can never be put to the test. Agnostics are fence sitters, they're too afraid or ignorant to to either believe or not believe.

the particular science that can explain such a thing is either theology or philosophy, as long as it is not something Natural.

The origins of man, or how the physical world operates is a natural thing. Theology and philosophy aren't sciences, they are more broad than that. Philosophers and scientists have tried to explain natural phenomena using rational arguments, but they are only arguments. You can't prove anything with philosophy or theology. The only way to know the origins of man is through science and patience.