Belief: The subjective assessment of uncertainty, quantified by probability.
When asked whether I "believe" in something, I interpret the question as "to what extent is this thing likely to be true, based on available evidence, experience, anecdotes, or intuitions?" I would argue that what identifies a good scientist is the relative weighting of each of those 4 markers of probability, with empirical evidence being weighted much more heavily than the other 3, and usually in that order. If enough evidence is available, the other 3 markers tend to not even factor into the assessment of belief.
For a scientist, belief is an obligate condition, imposed by the unavoidably subjective interpretation of the available evidence. Assuming this is true, then the only reason that two scientifically minded individuals would disagree on a belief would be that they have been exposed to different evidence, or weighted the evidence differently. Reconciling their beliefs is then a simple matter of putting as much evidence on the table as possible for examination and criticism.
