I'm going to have a lot to say about causes in the coming episode, and I'll start gathering citations here with this passage from William Paley's Natural Theology published in 1809;
Another system [that proposed by Erasmus Darwin], which has lately been brought forward, and with much ingenuity, is that of appetencies. The principle, and the short account, of the theory, is this: Pieces of soft, ductile matter, being endued with propensities or appetencies for particular actions, would, by continual endeavours, carried on through a long series of generations, work themselves gradually into suitable forms: and, at length, acquire, though perhaps by obscure and almost imperceptible improvements, an organization fitted to the action which their respective propensities led them to exert. A piece of animated matter, for example, that was endued with a propensity to fly, though ever so shapeless, though no other we will suppose than a round ball, to begin with, would, in a course of ages, if not in a million of years, perhaps in a hundred millions of
[page] 432
years (for our theorists, having eternity to dispose of, are never sparing in time), acquire wings. The same tendency to loco-motion in an aquatic animal, or rather in an animated lump which might happen to be surrounded by water, would end in the production of fins: in a living substance, confined to the solid earth, would put out legs and feet; or, if it took a different turn, would break the body into ringlets, and conclude by crawlingupon the ground.
Although I have introduced the mention of this theory into this place, I am unwilling to give to it the name of an atheistic scheme, for two reasons; first, because, so far as I am able to understand it, the original propensities and the numberless varieties of them (so different, in this respect, from the laws of mechanical nature, which are few and simple), are, in the plan itself, attributed to the ordination and appointment of an intelligent and designing Creator: secondly, because, likewise, that large postulatum, which is all along assumed and presupposed, the faculty in living bodies of producing other bodies organized like themselves, seems to be referred to the same cause; at least is not attempted to be accounted for by any other. In one important respect, however, the theory[page] 433
before us coincides with atheistic systems, viz. in that, in the formation of plants and animals, in the structure and use of their parts, it does away final causes. Instead of the parts of a plant or animal, or the particular structure of the parts, having been intended for the action or the use to which we see them applied, according to this theory, they have themselves grown out of that action, sprung from that use. The theory therefore dispenses with that which we [Creationists] insist upon, the necessity, in each particular case, of an intelligent, designing mind, for the contriving and determining of the forms which organized bodies bear. Give our philosopher these appetencies; give him a portion of living irritable matter (a nerve, or the clipping of a nerve), to work upon; give also to his incipient or progressive forms, the power, in every stage of their alteration, of propagating their like; and, if he is to be believed, he could replenish the world with all the vegetable and animal productions which we at present see in it.
We will, I think, begin to better understand the ancient Academic objections to Epicureanism if we first understand why Charles Darwin's theory of evolution constituted such a body blow to the theological and philosophical synthesis of Platonism and Christianity.