JCSBimp's Hexagonal Orthogonal

What do you call someone who believes that everything that is genuinely real, is real regardless of what they (or anyone) believe? I.e., they do not believe that what/whether/how they believe has an influence on what truly exists.

Because I sometimes think such a belief/non-belief system appeals to me intellectually, but there are still ways (magickal thinking?) that I am not precisely there: I am, specifically, not even sure that adequately describes all the ways reality, objective verifiability, and belief are connected.

Are there ways in which what I believe now (time mark 1) influences what I experience/observe of reality now (time mark 2)?