Tuesday, April 24, 2018

I Didn't Know This. Did You?

When was the theory of evolution proposed? answered by Ben Waggoner on Quora
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You can click the link above to read Ben's answer in Quora, or just scroll down for the article. I'm sharing it in whole because the Embed Share feature doesn't show the entire article in Blogger.
The Greek philosopher Anaximander is said to have opined that humans came from fish, although his own writings have not survived. I don’t think we know whether he had a definite “theory of evolution” in anything like the modern sense of the word. A 3rd century Roman writer claims that Anaximander believed that the first humans appeared as embryos inside the bodies of fish, which themselves came from mud and water; later, they burst out of the fish and could survive on their own. Frankly, this sounds weird. But I hesitate to judge Anaximander’s ideas based on nth-hand reports from about 700 years after he lived. (Anaximander)
But the Roman poet Lucretius did come up with a pretty well-sketched-out scenario of the entire universe evolving from atoms, subject to the laws of nature and the workings of chance, in his poem De rerum natura, written in the middle of the first century BCE. Lucretius probably didn’t come up with all of this himself—he was trying to explain and expound on Epicurean philosophy, which began with the work of Epicurus around 300 BCE. Lucretius explained that Earth had given birth to all living things. Since Earth could still spontaneously generate simple life forms like worms and such, it wasn’t surprising that Earth had once given birth to larger and more complex plants and animals:
Thus then the new Earth first of all put forth
Grasses and shrubs, and afterward begat
The mortal generations, there upsprung—
Innumerable in modes innumerable—
After diverging fashions. For from sky
These breathing-creatures never can have dropped,
Nor the land-dwellers ever have come up
Out of sea-pools of salt. How true remains,
How merited is that adopted name
Of earth—"The Mother!"—since from out the earth
Are all begotten. And even now arise
From out the loams how many living things—
Concreted by the rains and heat of the sun.
Wherefore 'tis less a marvel, if they sprang
In Long Ago more many, and more big,
Matured of those days in the fresh young years
Of earth and ether. . . .
Wherefore, again, again, how merited
Is that adopted name of Earth—The Mother!—
Since she herself begat the human race,
And at one well-nigh fixed time brought forth
Each beast that ranges raving round about
Upon the mighty mountains, and all birds
Aerial with many a varied shape.
But, lo, because her bearing years must end,
She ceased, like to a woman worn by eld. . . .
In suchwise, then, the lapsing aeons change
The nature of the whole wide world, and earth
Taketh one status after other. And what
She bore of old, she now can bear no longer,
And what she never bore, she can to-day.
There’s a sort of foreshadowing of natural selection here, because Lucretius argues that Earth also produced monsters and strange beings—which, however, have died out because they weren’t well adapted for life.
In those days also the telluric world
Strove to beget the monsters that upsprung
With their astounding visages and limbs—
The Man-woman—a thing betwixt the twain,
Yet neither, and from either sex remote—
Some gruesome Boggles orphaned of the feet,
Some widowed of the hands, dumb Horrors too
Without a mouth, or blind Ones of no eye,
Or Bulks all shackled by their legs and arms
Cleaving unto the body fore and aft,
Thuswise, that never could they do or go,
Nor shun disaster, nor take the good they would. . . .
And in the ages after monsters died,
Perforce there perished many a stock, unable
By propagation to forge a progeny.
For whatsoever creatures thou beholdest
Breathing the breath of life, the same have been
Even from their earliest age preserved alive
By cunning, or by valour, or at least
By speed of foot or wing. And many a stock
Remaineth yet, because of use to man,
And so committed to man's guardianship. . . .
. . . But those beasts to whom
Nature has granted naught of these same things—
Beasts quite unfit by own free will to thrive
And vain for any service unto us
In thanks for which we should permit their kind
To feed and be in our protection safe—
Those, of a truth, were wont to be exposed,
Enshackled in the gruesome bonds of doom,
As prey and booty for the rest, until
Nature reduced that stock to utter death.
This doesn’t look much like a “theory” in the modern sense, but I would argue that it’s not too wide of the mark to call it one. Lucretius is proposing a naturalistic scenario for how life began and changed, and while he doesn’t go out and test it, or particularly encourage readers to do so, he does appeal to observations and experience to support his scenario. And he avoids teleology: the Earth and the life on it weren’t created for us, or for any higher purpose. In the end it’s all atoms and the void.

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