The positivist dislikes the idea that there should be meaningful problems outside the field of ‘positive’ empirical science—problems to be dealt with by a genuine philosophical theory. He dislikes the idea that there should be a genuine theory of knowledge, an epistemology or a methodology. He wishes to see in the alleged philosophical problems mere ‘pseudo-problems’ or ‘puzzles’. Now this wish of his—which, by the way, he does not express as a wish or a proposal but rather as a statement of fact—can always be gratified. For nothing is easier than to unmask a problem as ‘meaningless’ or ‘pseudo’. All you have to do is to fix upon a conveniently narrow meaning for ‘meaning’, and you will soon be bound to say of any inconvenient question that you are unable to detect any meaning in it. Moreover, if you admit as meaningful none except problems in natural science, any debate about the concept of ‘meaning’ will also turn out to be meaningless. The dogma of meaning, once enthroned, is elevated forever above the battle. It can no longer be attacked. It has become (in Wittgenstein’s own words) ‘unassailable and definitive’. [29-30]
When I wrote my Logik der Forschung I thought that the quest for the meanings of words was about to end. I was an optimist: it was gaining momentum. The task of philosophy was more and more widely described as concerned with meaning, and this meant, mainly, the meanings of words. And nobody seriously questioned the implicitly accepted dogma that the meaning of a statement, at least in its most explicit and unambiguous formulation, depends on (or is a function of) that of its words. This is true equally of the British language analysts and of those who follow Carnap in upholding the view that the task of philosophy is the “explication of concepts”, that is, making concepts precise. Yet there simply is no such thing as an “explication”, or an “explicated” or “precise” concept.
However, the problem still remains: what should we do in order to make our meaning clearer, if greater clarity is needed, or to make it more precise, if greater precision is needed? In the light of my exhortation the main answer to this question is: any move to increase clarity or precision must be ad hoc or “piecemeal”. If because of lack of clarity a misunderstanding arises, do not try to lay new and more solid foundations on which to build a more precise “conceptual framework”, but reformulate your formulations ad hoc, with a view to avoiding those misunderstandings which have arisen or which you can foresee. And always remember that it is impossible to speak in such a way that you cannot be misunderstood: there will always be some who misunderstand you. If greater precision is needed, it is needed because the problem to be solved demands it. Simply try your best to solve your problems and do not try in advance to make your concepts or formulations more precise in the fond hope that this will provide you with an arsenal for future use in tackling problems which have not yet arisen. 
[T]he quest for precision, in words or concepts or meanings, is a wild-goose chase. There simply is no such thing as a precise concept (say, in Frege’s sense), though concepts like “price of this kettle” and “thirty pence” are usually precise enough for the problem context in which they are used. (But note the fact that “thirty pence” is, as a social or economic concept, highly variable: it had a different significance a few years ago from what it has today.)
Frege’s opinion is different; for he writes: “A definition of a concept … must determine unambiguously of any object whether or not it falls under the concept … Using a metaphor, we may say: the concept must have a sharp boundary.” But it is clear that for this kind of absolute precision to be demanded of a defined concept, it must be demanded of the defining concepts, and ultimately of our undefined, or primitive, terms. Yet this is impossible. For either our undefined or primitive terms have a traditional meaning (which is never very precise) or they are introduced by so-called “implicit definitions”—that is, through the way they are used in the context of a theory. This last way of introducing them—if they have to be “introduced”—seems to be the best. But it makes the meaning of the concepts depend on that of the theory, and most theories can be interpreted in more than one way. As a result. implicitly defined concepts, and thus all concepts which are defined explicitly with their help, become not merely “vague” but systematically ambiguous. And the various systematically ambiguous interpretations (such as the points and straight lines of projective geometry) may be completely distinct.
This should be sufficient to establish the fact that “unambiguous” concepts, or concepts with “sharp boundary lines”, do not exist. [28-9]
[B]oth precision and certainty are false ideals. They are impossible to attain, and therefore dangerously misleading if they are uncritically accepted as guides. The quest for precision is analogous to the quest for certainty, and both should be abandoned.
I do not suggest, of course, that an increase in the precision of, say, a prediction, or even a formulation, may not sometimes be highly desirable. What I do suggest is that it is always undesirable to make an effort to increase precision for its own sake—especially linguistic precision—since this usually leads lo loss of clarity, and to a waste of time and effort on preliminaries which often turn out to be useless, because they are bypassed by the real advance of the subject: one should never try to be more precise than the problem situation demands.
I might perhaps state my position as follows. Every increase in clarity is of intellectual value in itself; an increase in precision or exactness has only a pragmatic value as a means to some definite end—where the end is usually an increase in testability or criticizability demanded by the problem situation (which for example may demand that we distinguish between two competing theories which lead to predictions that can be distinguished only if we increase the precision of our measurements). [24-5]