I hold that the only valid means to justify a…

I hold that the only valid means to justify a belief as it being true in order for its embrace, is through the main stream science epistemological system. It is part rationalist, part empiricist and part pragmatic.
However, I also hold that rationalism often needs to be confirmed by observation. As I am sure most of you know, the assumptions or implications of theorems, however logically consistent, need to be confirmed by observation before they can be regarded as true. If such was not the case, the M theory would already be science.
It stands to reason that what is true by virtue of meaning, is not necessarily true of objective reality. As Eugene Wigner said of maths: “they are *unreasonably effective in describing the universe.

What a arguments have you to dismiss empiricism, rationalism or pragmatism as the only effective means to acquire knowledge?.
Also, do you employ any other epistemological system?. If so, how do you asses its effectiveness in regards to the acquisition of knowledge?

(By the way, I made another post. If it is not approved before I go idle, please do not hold it against me)