Much of the knowledge in any field is tacit, that is to say not explicit in the writings of those working in the field, but held instead as mental representations communicated between thinkers viva voce, in lectures, seminars, tutorials, and most importantly in conversation. The degree to which a field is tacit and explicit varies considerably, with the humanities being towards the the tacit end of the scale and the sciences towards the explicit end. Mathematics is as explicit as any, but I understand from my acquaintances in that area that much knowledge there is in fact tacit.

It is interesting to note that that a concrete and information rich study such as history tends toward the tacit, while the abstract and informationally selective field, such as physics, tends towards the explicit. This point underlies the very much less helpful subjective/objective distinction. That is to say, being relatively explicit, the sciences are in a better position to reach intersubjective agreement on novel propositions; while the humanities rely to such a degree on tacit understanding that this level of within group agreement inhibits, obscures and can be mistaken for free discussion and testing of fresh ideas.