(1) Epistemology is looking for a definition of knowledge.

(2) Suppose an epistemologist claims that he has come upon a correct definition, this claim would amount at saying " now, I know what is the correct definition of knowledge".

(3) He cannot use his alledged definition of knowledge to assess his own claim, that would be circular.

(4) He cannot use another definition, for the definition he has found is alledgedly the only correct one.

In brief, epistemology is impossible, for we should know what is knowledge in order to look for a knowledge of knowledge and to bring this research to its completion.

One answer could be : knowing that P is not the same thing as knowing that one knows P, but, what would be an epistemology that would not be a claim to know anything?

Are there any references that may be pointed to concerning this way of questionning the possibility of epistemology?

  • 2
    This is a version of what is called Agrippa's trilemma, with a horn missing. It is half-valid assuming the Aristotelian ideas of definition and justification, or, more broadly, foundationalist ones. Foundationalists typically get out of it by postulating "basic knowledge" of some sort that need not be "assessed" (the missing horn). Non-foundationalists deny (1) in the intended sense of "definition", epistemology is to describe and organize knowledge, make it coherent, not "define" it, except in a practical sense.
    – Conifold
    Nov 16, 2019 at 22:49
  • Formal axiomatic systems need one or more an undefined terms. This does not limit knowledge since knowledge may not be in the form of such a system. You're assuming knowledge is a matter of definitions and calculations, but this is not a comprehensive view. If you are in pain you know it, and no amount of linguistic/conceptual analysis will change this. . .
    – user20253
    Nov 17, 2019 at 13:04
  • This related SE Philosophy post may be of interest: philosophy.stackexchange.com/questions/6413/…
    – J D
    Nov 17, 2019 at 20:44

3 Answers 3


We distinguish propositional knowledge (knowledge-that), knowledge-how, and knowledge by acquaintance, at least these three. It may be, but we should not assume, that 'knowledge' has the same sense or meaning in all three cases.

It is hard to get your question off the ground. For we need to know what a definition is - the sense or meaning of 'definition' - before we can know whether a particular definition of 'knowledge' is correct.

I assume, but I may be wrong, that the question centres on propositional knowledge (knowledge-that).

There seem to be two ways of elucidating this concept. One is simply Wittgensteinianly to 'look for the use'. How does a language community use the term 'knowledge' When we have established this, and there may be a range of uses, we have 'the definition'. There is no more to definition than usage. 'But don't we need to know that we have established the community's usage?' Why shouldn't correct belief be enough?

The other way is to consider functionally the question of the nature of knowledge. We have the concept of belief; we have the concept of correct or true belief? Why do we need, as well as these, another concept - that of knowledge? What is this extra concept functional to?

E.J. Craig suggested in 'The Practical Explication of Knowledge' that what knowledge introduces is the notion of non-accidental truth. Mere belief, or mere correct or true belief, is unreliable. Unless the grounds or explanation of a belief are non-accidental, its connection with truth is accidental. A belief counts as knowledge if there is a reliable, non-accidental connection between a belief and its truth. I would count this as a functional definition of knowledge, and one that avoids the paradoxical requirement to know what knowledge is before we can tell whether the definition is correct.


Edward Craig, 'The Practical Explication of Knowledge', Proceedings of the Aristotelian Society, New Series, Vol. 87 (1986 - 1987), pp. 211- 226.


One might say that the argument is a very straightforward reason to believe, not that epistemology is meaningless, but that its concept (knowledge) is irreducible to other concepts. The Stanford Encyclopedia of Philosophy discusses this, at least in the article on John Cook Wilson (I thought I could find a reference to Timothy Williamson's statement of the same thesis, but I didn't find it...):

Cook Wilson believed that “our experience of knowing then being the presupposition of any inquiry we can undertake, we cannot make knowing itself a subject of inquiry in the sense of asking what knowing is” (SI, 39). This leads to his main thesis concerning knowledge, namely that it is not definable in terms of something else. In particular, it is not to be defined in terms of belief augmented by some other property or properties, as in the traditional view of knowledge as ‘justified true belief’.

Here's an IEP article that's relevant: https://www.iep.utm.edu/meta-epi/


... and the dictionary being just a set of self-references would be completely useless.

You've just noticed that knowledge (not only regarding the term) is based on a set of tautologies. Kant already suggested that. In such case we can take it to the extreme: you are asking a useless question, since any answer would be based on facts you already know.

But the essential fact behind is that knowledge is not just a set of entities (Kant's "concepts"), but also a set of logical relationships (a concept in a dictionary is a relationship with other concepts: a dictionary is just a set of references). Your question, therefore, deals not about finding new concepts, but moreover new relationships between concepts you already have. Your dictionary lacks of some relationships among already existing terms.

A secondary fact is related to the most criticized issue regarding Kant: language can approximately reflect knowledge, but it usually with a quite poor level of precision. When you walk the sand and feel something, you might try to express it, but it is actually impossible to use language for that. Art is better for such purpose (you can use music, sculpture, hand shoe making), but it is far from being precise. And Kant dismissed the imprecisions of language. Reason cannot factually be described by language with precision, nor the facts raising from it. For example, 'yellow' could or not be a concept; raises moreover a feeling, than cannot be expressed with language. In such case, reason is not only like a dictionary, a set of references to other concepts, but also a set of references with feelings, desires, faculties, etc.

Consider a third fact, in addition: even scientific knowledge is not such thing if it is written in a book which no one reads. So, even scientific knowledge has a load of subjectivity. You would ask "wasn't it objective???", yes, since objectivity is shared subjectivity (any scientific fact depends on a lot of subjective elements and beliefs, and it is objective when such subjective elements are shared between two individuals). Absolute objectivity is impossible, it would imply that a martian would agree with all science. But perhaps martians have other subjective ideas, perceptions, capabilities. Absolute objectivity implies complete denial of subjectivity, and that's impossible (see Berkeley, Hume).

Having such elements in mind, perhaps you get an answer. Knowledge comes to be a subjective (fact 3) model of reality, consisting in relationships (fact 1) between concepts and physiological faculties (fact 2). Epistemology implies the attempt to model such subjectivity, by means of the physiological capabilities we have. So, 'epistemology is the study of knowledge' is correct, whilst considering the three aforementioned facts. If such facts are ignored ---concepts would just be isolated objects, concepts would be absolutely precise, concepts would be absolutely objective---, yes, in such case, robotic-epistemology is impossible.

Epistemology is the mirror reason uses to model itself. Your argument would be equivalent to state that one cannot look oneself using a mirror because mirror contents are not reality. That's arbitrary. While a mirror shows not reality, it usually provides enough information for the goals it serves to.

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