I have to accept that you are speaking of merely cognitive reasoning. Beliefs are often formed by unconscious reasoning. Not much of the population exercises cognitive reasoning, “thinking”. But then we are actually talking about the evidence involved in science and the associated reasoning. Without cognitive reasoning, it can’t be science at all. Cognitive reasoning is what allows for communication and verification of speculations (aka “science”).
So it is really an issue of credible evidence, not presumed beliefs. Evidence accepted yet not questioned is not credible evidence. One cannot be certain that his evidence is credible until he reasons that it is credible.
But even on the subconscious level, what you sense as “belief” is actually the result of subconscious reasoning. If the subconscious cannot use its reasoning to form a belief, there will not be any belief presented to the conscious. To the subconscious, there was no evidence with which to form a belief. And even on the unconscious level, all sensing (the source of evidence) is the result of actual reasoning, such as “because this particular nerve was triggered, something touched my arm” or "because light appeared at this point on my retina, light is being emitted from that point in space".
There is reasoning on every level of “evidence” else that level of mind does not accept even a belief.