More from Dawkins’ The Greatest Show on Earth:

As we trace the ancestry of modern Homo sapiens backwards, there must come a time when the difference from living people is sufficiently great to deserve a different specific name, say Homo ergaster. Yet, every step of the way, individuals were presumably sufficiently similar to their parents and their children to be placed in the same species. Now we go back further, tracing the ancestry of Homo ergaster, and there must come a time when we reach individuals who are sufficiently different from “mainstream” ergaster to deserve a different specific name, say Homo habilis. And now we come to the point of this argument. As we go back further still, at some point we must start to hit individuals sufficiently different from modern Homo sapiens to deserve a different genus name: say Australopithecus. The trouble is, “sufficiently different from modern Homo sapiens” is another matter entirely from “sufficiently different from the earliest Homo“, here designated Homo habilis. Think about the first specimen of Homo habilis to be born. Her parents were Australopithecus. She belonged to a different genus from her parents? That’s just dopey! Yes it certainly is. But it is not reality that’s at fault, it’s our human insistence on shoving everything into a named category. In reality, there was no such creature as the first specimen of Homo habilis. There was no first specimen of any species or any genus or any order or any class or any phylum. Every creature that has ever been born would have been classified – had there been a zoologist around to do the classifying – as belonging to exactly the same species as its parents and children. Yet, with the hindsight of modernity, and with the benefit – yes, in this one paradoxical sense benefit – of the fact that most of the links are missing, classification into distinct species, genera, families, orders, classes and phyla becomes possible. (The Greatest Show on Earth, Chapter Seven, pp. 195–196.)

He gets to the heart the confusion underlying this point earlier in the book, where he shows how Plato’s “theory of forms” – termed “essentialism” today – led to the theory of evolution being so counter-intuitive:

For Plato, the “reality” that we think we see is just shadows cast on the wall of our cave by the flickering light of the camp fire. Like other classical Greek thinkers, Plato was at heart a geometer. Every triangle drawn in the sand is but an imperfect shadow of the true essence of a triangle…

Biology…is plagued by its own version of essentialism. Biological essentialism treats tapirs and rabbits, pangolins and dromedaries, as though they were triangles, rhombuses, parabolas or dodecahedrons. The rabbits that we see are wan shadows of the perfect “idea” of rabbit, the ideal, essential, Platonic rabbit, hanging somewhere out in conceptual space along with all the perform forms of geometry. Flesh-and-blood rabbits may vary, but their variations are always to be seen as flawed deviations from the ideal essence of rabbit.

How desperately unevolutionary that picture is! The Platonist regards any change in rabbits as a messy departure from the essential rabbit, and there will always be resistance to change – as if all real rabbits were tethered by an invisible elastic cord to the Essential Rabbit in the Sky. The evolutionary view of life is radically opposite. Descendants can depart indefinitely from the ancestral form, and each departure becomes a potential ancestor to future variants. Indeed, Alfred Russel Wallace, independent co-discoverer with Darwin of evolution by natural selection, actually called his paper “On the tendency of varieties to depart indefinitely from the original type”.

If there is a “standard rabbit”, the accolade denotes no more than the centre of a bell-shaped distribution of real, scurrying, leaping, variable bunnies. And the distribution shifts with time. As generations go by, there may gradually come a point, not clearly defined, where the norm of what we call rabbits will have departed so far as to deserve a different name. There is no permanent rabbitness, no essence of rabbit hanging in the sky, just populations of furry, long-eared, coprophagous, whisker-twitching individuals, showing a statistical distribution of variation in size, shape, colour and proclivities…the reason Darwin was such an unconscionable time arriving on the scene was that we all – whether because of Greek influence or for some other reason – have essentialism burned into our mental DNA. (The Greatest Show on Earth, Chapter Two, pp. 21–23.)

The question “what is a cat, really?” or “what is the ‘ultimate reality’ of a cat?” that we saw in the Ultimate reality entry implicitly contains within it this idea of “essentialism” – it assumes that there is some “essence of cat hanging in the sky” which is waiting to be found, but this is simply not true. “Ultimate catness” is “no more than the centre of a bell-shaped distribution of real” cats, and the search for some kind of “ultimate reality of a cat” is a wild and definitely religious goose chase.

Modern hermeticism – from which the so-called “Western esoteric tradition” and modern occultism ultimately originate – has this idea of a “thing-in-itself” at its very heart:

“Under, and back of, the Universe of Time, Space and Change, is ever to be found The Substantial Reality – the Fundamental Truth.’ – The Kybalion.

“Substance” means: “that which underlies all outward manifestations; the essence; the essential reality; the thing in itself”, etc. “Substantial” means: “actually existing; being the essential element; being real”, etc. “Reality” means: “the state of being real; true, enduring; valid; fixed; permanent; actual”, etc.

Under and behind all outward appearances or manifestations, there must always be a Substantial Reality. This is the Law. Man considering the Universe, of which he is a unit, sees nothing but change in matter, forces, and mental states. He sees that nothing really IS, but that everything is BECOMING and CHANGING…And if he be a thinking man, he realizes that all of these changing things must be but outward appearances or manifestations of some Underlying Power – some Substantial Reality.

All thinkers, in all lands and in all times, have assumed the necessity for postulating the existence of this Substantial Reality. All philosophies worthy of the name have been based upon this thought. (The Kybalion, Chapter Four, pp. 53–54.)

The Platonic influence on Hermeticism – and therefore on modern occultism – is striking; the idea of “Substantial Reality” which “underlies all outward manifestations” is equivalent to “essentialism” and to Plato’s “theory of forms”. We have seen that, in the case of living creatures at least, there is no “essence of rabbit” or “essence of cat”, and we have seen how the deconstruction of all objects ultimately into subatomic particles reveals that there is no “essence” of any other object, either. The absence of such an “essence” – of such an “ultimate reality” – pulls the rug from under the entire “Western esoteric tradition”, and reveals the whole philosophy behind it to be built on sand; occultists in the Hermetic tradition are clinging to an outmoded philosophy which modern science has shown to be illusory.