Let's say that there is no free will.

This necessarly means that we are making the statement above only and soley because we are deterministically (or randomly) compelled to do so, and not because of critical thinking and rational choiche.

Ok, fine. So how we determine whether our (100% compelled and coerced) statement is true?

It's no easy. There is no critical thinking left. No proving of persuading people that A is more sound than B, no act of choosing between two or more possibilities.
There are only pre-determined (or random) outcomes. Reality compelling some of us to think A rather than B, or B rather than A.

So, it seems to me, our best and only option is to faithfully believe that reality is (deterministically or randomly) somehow, mysteriously and benevolently forcing us - but not all of us... why? Why are we so blessed? - toward the correct conclusions.

Is this a good scientifical approach?