I Wonder....

How about this guy?
He seems pretty rigorous!

If you gave a brilliant and rigorous thinker a list of sufficiently rigorous axioms, postulates, and values, could he flesh out an entire worldview that would be perfectly rational?

I am inclined to think that he could. If he were given assigned framework, and also reassured that he would not actually have to believe in his conclusions (since presumably his axioms and values are different from the ones that he was assigned) then I think that actually fleshing out the worldview would become something like a grind. He would make the logically necessary inferences, process the available data, and make relative measurements of probability. Any bias that creeped in would, I imagine, be due to his body trying to find mental shortcuts to avoid expending too much energy, he would not need to incorporate a bias to skew the worldview toward his own values because the entire project would be understood as a hypothetical fleshing out. The inferences only stand insofar as the axioms, postulates, and values are held - he would be safe from any horrifying conclusions because he does not have to share the basic assumptions.

Of course there would be the matter of insufficient empirical data. But that would be no great matter, because he could, in accordance with his assigned assumptions, develop his own "scientific method" that would make all empirical processing just a matter of going through the steps to obtain more measurements and rules for processing the probability of all theories and explanations of empirical measurements.

In fact, our thinker could do away with "belief" altogether. Instead of asking whether or not you believe a proposition, you could turn the entire enterprise into nothing but statements of fact. Instead of asking, "do you believe that there is a city called New York in North America," and the person responding with the binary "yes, I do," or "no, I don't," instead the conversation could be conducted this way, "is there a city called New York in North America" the response would be, "there is 99.9% certainty that there is such a city." Belief and acceptance of propositions would be a necessary evil that would arise as a result of individuals not being aware of the results of probability measurements; the proper and rigorous way to talk about the world would be by talking in measured probabilities. Shades instead of binaries.

Disputes about the probabilities of of a given proposition would not arise, as there would be a clear, publicly available method of calculating probabilities in accordance with the assumed rules. Any deficiencies with the method would be corrected once it was shown that another method furthered the assumed values more fully without violating an assumed truth.

Reasonable disagreement would be impossible. All disagreement would be failure to understand the probabilities calculated by the method.

The method would take the available evidence and the available theories and calculate the extent to which each theory explained the evidence, the extent to which the theory retains unexplained ambiguities, the extent to which the theory conflicted with other available evidence; any theory that contradicted an assumption or that contradicted itself (assuming the impossibility of contradiction is one of the assumptions) would instantly be disregarded as impossible. The available theories could then be assigned numerical values that reflected how their probability stands in relation both to each other as competing theories and the entire body of theories in all disciplines.

In this way, the entire universe, insofar as human beings can perceive it, could be organized into a monolithic body of knowledge and statement of fact. All of it public, clear, and factual. All by that rigorous thinker and his assigned assumptions.

The reason that this will never happen in real life is that we do not have such assigned assumptions. Disagreement takes place at the basic level, at the area that in this little scenario was covered up by assigned assumptions. It is only for this reason that we can have belief, assent, reasonable disagreement, or any kind of diversity of thought. Because when you follow a line of reasoning back far enough, you will come to something personal. Without this, we could reduce the whole enterprise of thought to a method.