Anti-essentialism is a Popperian idea that many people are either unaware of or do not understand. Many people are essentialists, particularly people who think they understand philosophy, but essentialism is a bad mistake. There are two separate ideas that Popper criticises. (1) Essentialism is the idea that reality consists of ultimate essences and we ought to try to explain what we see in terms of ultimate essences. (2) There is another closely connected idea: we ought to define our terms before we start a discussion otherwise we might get lost.
Let’s take point (1) first. Suppose that reality does consist of ultimate essences. Whatever they are we don’t have direct access to them and so the idea that we should use them seems to require knowledge we don’t have. What would an explanation in terms of essences look like? We start with terms like “cat” and then define the essence of a cat by listing all the features that all cats have in common: whiskers, weird looking eyes, make meowing noises and so on. We would then take all of the cat features and use them to explain what cats do. The problem is that each time we define an essence we use many undefined terms and so we would have to define the new undefined terms and we would get into an infinite regress without ever explaining anything. Nor can definitions reduce ambiguity, as mentioned in point (2): every definition we introduce uses undefined ambiguous terms.
Popper suggests that a better way of thinking about definitions is that a defined terms should be used as shorthand for a longer description: methodological nominalism. So instead of saying “negatively charged particle with spin-1/2 and about 1/1000 the mass of a proton” we say “electron” as a shorthand.
Furthermore, if we try to explain things in terms of ultimate essences we might be tempted to think the ideas we have tell us what the essences are and that would be bad because we might be wrong. An example of this: I have seen some philosophical discussions in which the participants start the discussion by defining knowledge as justified true belief and discussing that definition. The discussion didn’t go anywhere because there was nowhere for it to go: the problem had been set up in such a way that it was completely unsolvable.
One last comment I should make that I don’t think was made by Popper, although I could be wrong. It seems to me there’s another reason to reject essentialist methods: it takes explanations and breaks them up into pieces that are difficult to understand. Suppose we want to understand electrostatics: the forces between slowly moving charges. We find that sometimes two objects attract one another and sometimes they repel one another. We propose and test the idea that the force with which they do this varies as the inverse square of the distance between them. We also discover that the force between two objects isn’t determined by the distance between them and introduce different charges on the objects to explain this. Imagine trying to learn this by having a dictionary that defines charges, and distances between charges and forces and so on. You would have to try to take all these different definitions and put the information they give together in an order that would actually give you an explanation before you could understand electrostatics. You can’t start with an unexplained heap of definitions and then use them to work out a theory. You have to start with problems and explanations.
The best expositions of Popper’s anti-essentialism that I have been able to find are in The Open Society and Its Enemies, Vol. 2, Chapter 11, Section II and Conjectures and Refutations, Chapter 3, Section 3.
There is another good exposition in a long section of Unended Quest.
It is interesting to note that The Poverty of Historicism was derailed and turned into The Open Society and its Enemies when Popper was writing the section on essentialism and that raised so many issues that he had to write a different book.
One of my beefs with essentialism is that it converts practical people into anti-intellectuals when they encounter the useless and boring essentialist approach and they think “if that is the life of the mind, they can shove it…”.
Thinking aloud some more. Early in the 1980s I had the idea of taking some of Popper’s leading ideas, specifically non-justificationism, objective knowledge and anti-essentialism and instead of defending these theories in detail against critics (which usually resuted in conducting the debate on their own terms), to “unpack the content” of these ideas by exploring what it means if these ideas are taken on board and tested in a whole lot of different contexts. Actually I started the project with non-justificationism and objective knowledge but it soon became apparent that essentialism creates so many problems that it was added to the list.
The project got to the point of a plan for a book with an introduction and a synopsis of the way the various chapters might look. I passed to to a literary agent in Sydney and he sent it to the HO in London. The message came back that it looked interesting but it would not be accepted by a publisher because it fell between the two stools of academic philosophy and psychobabble.
FWIW, I believe that the error of essentialism arises because, within a person’s mind, each concept carries a sort of ‘flavour’, based on what else it is connected to in that mind. This flavour does have some value but one may falsely assume it to be something objective.
An extract from Unended Quest.
Everybody who has done some translating, and who has thought about it, knows that there is no such thing as a grammatically correct and also almost literal translation of any interesting text. Every good translation is an interpretation of the original text; and I would even go so far as to say that every good translation of a nontrivial text must be a theoretical reconstruction. Thus it will even incorporate bits of a commentary. Every good translation must be, at the same time, close and free. Incidentally, it is a mistake to think that in an attempt to translate a piece of purely theoretical writing, aesthetic considerations are not important. One need only think of a theory like Newton’s or Einstein’s to see that a translation which gives the content of a theory but fails to bring out certain internal symmetries may be quite unsatisfactory; so much so that if somebody were given only this translation he would, if he discovered those symmetries, rightly feel he had himself made an original contribution, that he had discovered a theorem, even if the theorem was interesting chiefly for aesthetic reasons. (Somewhat similarly, a verse translation of Xenophanes, Parmenides, Empedocles, or Lucretius, is, other things being equal, preferable to a prose translation.)
In any case, although a translation may be bad because it is not sufficiently precise, a precise translation of a difficult text simply does not exist. And if the two languages have a different structure, some theories may be almost untranslatable (as Benjamin Lee Whorf has shown so beautifully). Of course, if the languages are as closely related as, say, Latin and Greek, the introduction of a few newly coined words may suffice to make a translation possible. But in other cases an elaborate commentary may have to take the place of a translation.
In view of all this, the idea of a precise language, or of precision in language, seems to be altogether misconceived. If we were to enter “Precision” in the Table of ideas (see above), it would stand on the left-hand side (because the linguistic precision of a statement would indeed depend entirely on the precision of the words used); its analogue on the right-hand side might be “Certainty”. I did not enter these two ideas, however, because my table is so constructed that the ideas on the right-hand side are all valuable; yet both 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 to 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). 14
It will be clear that these views differ greatly from those implicitly held by many contemporary philosophers of science. Their attitude towards precision dates, I think, from the days when mathematics and physics were regarded as the Exact Sciences. Scientists, and also scientifically inclined philosophers, were greatly impressed. They felt it to be almost a duty to live up to, or to emulate, this “exactness”, perhaps hoping that fertility would emerge from exactness as a kind of by-product. But fertility is the result not of exactness but of seeing new problems where none have been seen before, and of finding new ways of solving them.
However, I will postpone my remarks on the history of contemporary philosophy to the end of this digression, and turn again to the question of the meaning or significance of a statement or a theory.
Having in mind my own exhortation never to quarrel about words, I am very ready to admit (with a shrug, as it were) that there may be meanings of the word “meaning” such that the meaning of a theory depends entirely on that of the words used in a very explicit formulation of the theory. (Perhaps Frege’s “sense” is one of them, though much that he says speaks against this.) Nor do I deny that, as a rule, we must understand the words in order to understand a theory (although this is by no means true in general, as the existence of implicit definition suggests). But what makes a theory interesting or significant-what we try to understand, if we wish to understand a theory-is something different. To put the idea first in a way which is merely intuitive, and perhaps a bit woolly, it is its logical relation to the prevailing problem situation which makes a theory interesting: its relation to preceding and competing theories: its power to solve existing problems, and to suggest new ones. In other words, the meaning or significance of a theory in this sense depends on very comprehensive contexts, although of course the significance of these contexts in their turn depends on the various theories, problems, and problem situations of which they are composed.