to wit man, upon another very small part, to wit that inanimate matter lying within his reach, is the rule by which cleanthes judges of the origin of the whole; and he measures objects, so widely disproportioned, by the same individual standard.  But to waive all objections drawn from this topic, I affirm, that there are other parts of the universe (besides the machines of human invention) which bear still a greater resemblance to the fabric of the world, and which, therefore, afford a better conjecture concerning the universal origin of this system.  These parts are animals and vegetables.  The world plainly resembles more an animal or a vegetable, than it does a watch or a knitting-loom.  Its cause, therefore, it is more probable, resembles the cause of the former.  The cause of the former is generation or vegetation.  The cause, therefore, of the world, we may infer to be something similar or analogous to generation or vegetation.

But how is it conceivable, said DEMEA, that the world can arise from any thing similar to vegetation or generation?

Very easily, replied Philo.  In like manner as a tree sheds its seed into the neighbouring fields, and produces other trees; so the great vegetable, the world, or this planetary system, produces within itself certain seeds, which, being scattered into the surrounding chaos, vegetate into new worlds.  A comet, for instance, is the seed of a world; and after it has been fully ripened, by passing from sun to sun, and star to star, it is at last tossed into the unformed elements which every where surround this universe, and immediately sprouts up into a new system.

Or if, for the sake of variety (for I see no other advantage), we should suppose this world to be an animal; a comet is the egg of this animal:  and in like manner as an ostrich lays its egg in the sand, which, without any further care, hatches the egg, and produces a new animal; so...

I understand you, says DEMEA:  But what wild, arbitrary suppositions are these!  What data have you for such extraordinary conclusions?  And is the slight, imaginary resemblance of the world to a vegetable or an animal sufficient to establish the same inference with regard to both?  Objects, which are in general so widely different, ought they to be a standard for each other?

Right, cries Philo:  This is the topic on which I have all along insisted.  I have still asserted, that we have no data to establish any system of cosmogony.  Our experience, so imperfect in itself, and so limited both in extent and duration, can afford us no probable conjecture concerning the whole of things.  But if we must needs fix on some hypothesis; by what rule, pray, ought we to determine our choice?  Is there any other rule than the greater similarity of the objects compared?  And does not a plant or an animal, which springs from vegetation or generation, bear a stronger resemblance to the world, than does any artificial machine, which arises from reason and design?