I've been reading a collection of essays on neo-Aristotelianism where they endorse the concept of essential properties. An essential property is an ontological concept, not a conceptual concept. The essential properties of a thing are part of the existence of that thing, independent of how any mind perceives or conceives of the thing. A dog, for example, is essentially a dog, and would be essentially a dog even if there were never humans around to classify it as a dog. The dog-ness is a part of the objective, natural description of a dog.

But how can that be true, when dog-ness is a fuzzy property? Is a wolf a dog? What about a wild dog of Africa? What about a dingo? What about a half-wolf, half-dog? It seems like the essentialist is obligated to respond to each of these questions either by saying "yes", or by postulating a new essential property. If he postulated a new essential property for each one, then what about a 1/4-wolf, 3/4 dog? What about a 1/8 wolf, 7/8 dog? At what ratio does the animal become a dog? If he continues to postulate new essential properties, it starts to seem like every individual has its own unique essential property, and the essential property of any individual is simply being that individual.

On the other hand, if the essentialist says that all of those things have the property of dog-ness, then dog-ness has pretty weak explanatory properties. There are many differences between wolves and dogs, but if they are all classified as dogs, then all of those differences are contingent.

This may not be the best example, but the point is that the difference between essential and accidental properties seems to be fuzzy. That is not problematic if the difference is merely conceptual, but how does it make sense if the difference is a metaphysical feature of the objective world?

  • See Okasha, Darwinian Metaphysics: Species and the Question of Essentialism:"Putnam (1975) claims that the true criterion for being a lemon is having the "genetic code" of a lemon - this, rather than any observable traits, is the essence of lemonhood, he claims". The consensus is that such "absolute" essentialism is incompatible with modern biology, but "relative" essentialism can be saved if relational properties are allowed in essences. This is combined with a sort of soft epistemicism about boundaries, whose discovery is left to empirical science.
    – Conifold
    Commented Sep 12, 2022 at 0:51
  • 1
    Indeed few contemporary philosophers endorse Aristotelian essentialism classifications of objects according to their "essences, laws, sameness relations, fundamental properties and how these map out the ontological space of the world" and that natural kinds exist permanently and independently of human reasoning. Some prefer to classify your dog kind as "relevant" and "interesting" kind rather than some eternal and clear "natural" kind, which is still extremely useful especially in scientific applications otherwise the statistical law of large numbers and inductive reasoning would not work... Commented Sep 12, 2022 at 4:23

3 Answers 3


Philosophy has few consensus positions, so "what philosophers think" will almost always be a scattershot answer.

The question you asked, is based on applying falsification testing to a claim -- basically extending Popper's methodological naturalism to philosophy. Popper endorsed this, but not all philosophers do.

ENOUGH do, however, for these sorts of test cases to have convinced most philosophers today that essentialism is doomed. And pulling on this thread -- may take you were most other philosophers have been reluctant to go.

The basic issue is that virtually nothing in our universe appears to have an essence. The Sorites paradox, about a pile of whatever, and the Ship of Theseus thought problem, illustrate that all objects we identify in our world are bundle objects. They remain "that object" for us, even when they lose some parts, or add other parts, or even have all of their parts replaced, bit by bit. I.E. -- objects do not reduce, and they cannot be identified uniquely.

This creates a major problem for physical reductionists, and for analytic philosophy in general.

For physical reductionists, the pragmatic physical reality, that originally convinced them of physicalism, basically has to be denied. This denial is called scientific realism, and it holds that there really ARE no higher level objects, the REAL realty is just the most fundamental of physics. We just identify higher level objects as a mental shorthand, since dealing with the reduced reality of our world is just too much work. There is in this view ultimately no hardness, solidity, picking things up, etc. That philosophers are reluctant to accept the unreality of our experienced world has been an ongoing challenge for reductionists. This has led most physicalists today to accept emergent physicalism, where higher level objects ARE real, as they emerge through some as yet TBD process for lower level structures.

However, the way those higher level objects CHANGE over time provides a massive challenge to analytic philosophy. If my car is in an accident, and has many body panels replaced, plus I decided to upgrade the engine as it was also damaged, and unreliable to start with, and I repainted it another color -- is this now the same car? Most of us treat it as the same, but this seems -- odd. Trying to reduce identity to its VIN number also does not work, as I could pry its VIN off and bolt on one from a junker. This would be illegal, but would not plausibly change my car into the old junker.

The problem for analytics is that it seems that, moment to moment, due to molecule losses and changes, and larger pieces being replaced, A=/=A for basically any object in our universe over time. And if A=/=A, then one cannot validly apply logic to it.

Enter essentialism. To be able to do logic on objects, if some essence is assumed for that object, then analytics can still be done. As Conifold's comment asserts above, many essentialists have tried to assert essences are reduced properties. These are things like DNA for dogs, or for a particular person -- or the VIN number for a car. However, DNA as a category does not work 100% of the time, as all animals go thru a single strand -- double strand life cycle, and sometimes members of a species have more or fewer strands, etc. And as you noted, the DNA criteria does not separate dogs from wolves, as they interbreed. Another classic essentialist reductionist argument was that water must be H2O, in all worlds, based on laws of physics. BUT -- physics laws change, and minor variations in the values of the Standard Model of Quantum Mechanics in a different world would lead H2O to have different properties from what we call water. These efforts to identify an essence through reduction -- all fail due to the bundle problem of reality. Bundled objects and categories are GENERALLY true, but every one has exceptions, and that includes the efforts to identify a reductionist justification for essences.

Personality/selfhood essentialists have a similar problem. As Hume noted, our selves are bundles. More recent thinking no longer identifies selfhood with the highly variable and fleeting experiences and thoughts that Hume identified as the self, and instead focus on more stable memories and inclinations (character). But while selfhood is not at variable as Hume asserted, our memories are added, and fade, and are sometimes wrong, and our inclinations change. So even a more stable version of self faces and essence problem. Spiritual dualists have an answer to this -- asserting an essence of "soul". BUT -- this leads to a massive complexity in spiritual dualism, as soul was initially introduced to solve the problem of consciousness. But if consciousness is a variable bundle, and souls are not, then souls don't help at all with consciousness! And the relation between an unchanging soul essence and self/agency/consciousness becomes a murky quagmire, which depending on the relation proposed, will face its own falsification tests.

Where reductionists go from there -- I don't know. Most I have read just look for confirmation from the "generally true" of their claimed reduced essence, and they don't look for the more exotic falsification tests. Denial of falsification testing, or else making the claim untestable in principle are the general reactions among the ideologically committed to seeing their ideas falsified.

Aside -- I noted that essentialism is needed for analytics to stay relevant to our world, and that this thread can lead you far from most contemporary philosophy. There is another alternative to analytics, which need A=A, and for truth to be absolute. The alternative is radical pragmatism, where truth is what is useful. Under radical pragmatism, analytics are recognized as invalid per their own criteria when applied to this world, but often highly useful anyway. This question of A=/=A, among others such as the Munchausen trilemma, the inability of any language to support analytics (see Two Dogmas of Empiricism), and the plurality of logic, have lead me to radical pragmatism.

  • Thanks for the detailed and informative answer. My one complaint with it is the references to Popper as if he invented the idea of a counterexample to a philosophical position. Zeno of Elea would be surprised to hear that. Commented Sep 15, 2022 at 16:17
  • @DavidGudeman -- Yes, both logical and empirical testing have been part of philosophy for -- forever. But so have been rationalizations to inoculate claims against those tests, as well as citing confirmations to reinforce a view, without looking for challenging cases. Popper articulated the importance of the first, vs the other two approaches to arriving at understanding, with a focus on science. Popper extended falsification with vigor to philosophy as well. He is a noteworthy recent advocate of the importance of falsification, and critic of confirmation bias and rationalizations.
    – Dcleve
    Commented Sep 15, 2022 at 17:06

I can’t really answer your question because I don’t know enough about essentialism to say anything useful. I understand roughly what it means for a concept to be fuzzy, but I have no idea what it might mean to say that an essence is fuzzy, if you are thinking that’s how it would go. I would be very surprised if there was an answer to your question at the general level. There are many different kinds of concept and different kinds of fuzziness.

But perhaps I can offer some remarks that might help to clarify your thinking about this. In order to do this, I shall rely on ordinary ways of speaking and thinking which would not necessarily stand up to close philosophical examination.

One example of fuzziness is an out-of-focus photograph. Another would be the effect of exposing the film for too long so that object in the picture moves during the exposure, which produces an indistinct image. We know that the objects in the picture are not really fuzzy, because we know how to take a picture that is clear.

The ancient puzzle about a heap of sand – there is no clear borderline between a heap and a collection of grains – is a different case. Here, the problem lies in the concept of a heap, which has a vague borderline. We have ways of handling sand that are capable of precision (a kilo of sand, or a cubic metre), but it is convenient to have the vaguer concepts and so language contains both. The cases of "mass nouns" like water, air, coal, wood are similar but also different, since there is no smallest object involved as there is in the case of sand, which consists of grains.

There are fuzzy objects, of course. Many stuffed animal toys, for example, are fuzzy. More generally, "fuzzy" applies to anything that has a surface that feels like fur. Fuzz is a mass of short, curly hairs. Clouds might be considered fuzzy because the water droplets peter out gradually and there is no clear border between the cloud and the clear air. Whether such cases as these would make fuzziness essential to anything is another question, of course; but I would think it was possible.

But fuzzy logic is designed to apply to different kinds of case; it might have been clearer to call them indeterminate, particularly in respect of truth and falsity. Its theoretical and philosophical value is not clear to me, and it may be that some people would be inclined to regard it as a fudge. But it certainly has value in practical contexts, such as those where binary decisions need to be made or when common ground needs to be found to resolve disagreements.

One kind of case would be temperature, colour, sound. Here, the core of the problem, to put it this way, is to reconcile an analogue phenomenon, that varies continuously, with binary decisions like drawing borders between hot, warm and cold or one colour and the next or high and low. Here, it is clear that the difficulty lies in incorporating the phenomena into our thinking.

Another kind of case is probability and uncertainty. Here the difficulty is often a matter of context, since probability and uncertainty often come into their own when insufficient data is available to give a conclusive answer. For example, most gambling games have very little that is fuzzy about them; even the probability of each outcome is perfectly clear. The uncertainty that underpins the game, is always, and must be, resolved. In the case of a weather forecast, the probability of each outcome is very hard to quantify, but a number makes comparison of one with another much easier.

There are, of course, many cases (and not just biological ones) where two cases might share properties, so that one could say that a particular animal was ¼ wolf and ¾ dog, though in this case, the numbers would probably depend on counting the number of ancestors of each species. The discovery of the platypus is a dramatic real-life example, as was the case of the black swan. In one case, it was a new species and in the other a modification to the concept (though not necessarily to our idea of the essence) of them. It is clear, I think, that neither dog-wolf nor platypus is in the least indeterminate or fuzzy. (Well, the platypus is fuzzy, but only in the way that a teddy bear might be fuzzy.) The problem here is that they pose a problem for our existing classifications. Fuzzy logic might help with this, although there are already ways in natural language for describing them. However, I couldn’t say what impact they might have on ideas of essence.

That’s about as far as I can go with this.

  • This is a very good discussion of fuzziness; unfortunately, it's not an answer to the question, so I can't accept it. Commented Sep 15, 2022 at 16:31
  • @DavidGudeman. Thanks for the compliment. I wasn't expecting you to accept the answer. From seeing the answer you did accept, I've learnt something about reading questions, which is as much as I could expect from the exercise.
    – Ludwig V
    Commented Sep 15, 2022 at 20:29

You are arguing against Evolution. Read "Real Essentialism" by David Oderberg a dog is a dog and you are trying to picture some ideal Fido and measuring others as nearer or farther from Fido.

It is an essential property of a human that he has height but not any particular height. Could be a foot-long baby or Wilt Chamberlain. You are introducing the variation that is part of the essence as if were a varying essence.

  • This looks like the core of a real answer to my question, but at this point it is too obscure and incomplete to accept. I have no idea, for example, what you mean by "you are arguing against Evolution". Commented Oct 3, 2022 at 21:10

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