In my last blog I characterized knowledge as methodically justified interpreted belief in order to make clear that it is impossible to say that there is a certain quantity of knowledge (be it measured in bytes or otherwise). I am not alone in characterizing knowledge that way. I want to mention here only Günter Abel, who has a related view (see his “Forms of Knowledge: Problems, Projects, Perspectives”, in Peter Meusberger, Michael Welker, Edgar Wunder (eds.), Clashes of Knowledge, Springer, 2008; pp. 10-33). However, that knowledge cannot be quantified is not only so because it is perspectival. Basically, the question “what is knowledge?” has no unequivocal answer, and what cannot be defined clearly cannot be measured. Take my own characterization of knowledge. Assuming that it is correct, even then it refers only to intellectual knowledge or “knowledge that”, as Ryle has called it, a type of knowledge that has to be distinguished from practical knowledge or “knowledge how” (see my blog dated June 9, 2008). Supposing that we could measure knowledge-that, we would measure only a part of what we know. Maybe all our knowledge-that, our theoretical knowledge, might be caught in books, articles and computer files (which I doubt), but how should we catch and measure all the things that we practically know how to do but that we cannot put into words? For how should we measure the knowledge how to skate or to drive a car, activities that can perhaps be theoretically explained but that we know to do only when we are successfully able to do it? Moreover, for everybody the knowledge how to do it is a bit different: my knowing how to skate is not exactly the same as your knowledge how to skate (for instance because our physical capacities are a bit different). Or what do you think of doing research? The main lines may be listed in handbooks, but many of the choices you have to make are simply a matter of your experience and intuition.
All this becomes even more complicated, when we look at other possible distinctions of knowledge. For besides the distinction between knowledge-that and knowledge how, other classifications can be made. Let me quote Abel just by way of illustration: We can “distinguish … between (a) everyday knowledge (knowing where the letterbox is), (b) theoretical knowledge (knowing that 2+2=4 or, within classical geometry, knowing that within a triangle the sum of the angles equals 180o), (c) action knowledge (knowing how to open a window), and (d) moral or orientational knowledge (knowing what ought to be done in a given situation). Across these [types] of knowledge … the following important distinctions and pairs of concepts have to be taken into account: (a) explicit and implicit (tacit) knowledge, (b) verbal and nonverbal knowledge, (c) propositional knowledge (that which can be articulated in a linguistic proposition) and nonpropositional knowledge (that which is not articulable within a that-clause), (d) knowledge relating to matters of fact and knowledge based on skills and abilities.” (Abel, id: 13).Should we measure all these different types of knowledge, add them, subtract what we counted more than once and then say: this is the amount of knowledge in the world? But how could we count or estimate everyday knowledge or implicit knowledge, for instance? And how could we say, which is a precondition for the counting task, that there is at least theoretically a fixed quantity of everyday knowledge or implicit knowledge in the world at a certain moment, for instance at 18.56h on November 14, 2011? I think that nobody would endorse the view that we can. But then the idea that there is a total amount knowledge is not realistic.