An article in USAToday entitled “Will We Be The First Martians” brings to mind an application of an important passage from Lucretius. Just as mankind today is about to take life to Mars — and probably already has through microscopic organisms on our unmanned probes — we should not presume that life “originated” here on Earth. Given the eternal nature of the universe, all uses of the term “originate” must be carefully considered, no less when considering “life” than when considering any other manifestation of the eternal and changing combinations of the elements.
In the passage below from Book II of De Rerum Natura, Lucretius states this proposition clearly. These facts “cry loud in proclamation” …. the vastness of the universe “holds innumerable seeds” … so “it must be unthinkable that our sky and our round world are precious and unique.”
The argument in full is well worth keeping in mind the next time you come across some oracular pronouncement that life on Earth “began” “such-and-such billions of years ago” at “such and such exotic locale.” Assertions of this sort fly in the face of the evidence cited by Lucretius. The truth is – The processes of Nature have marched forward, are marching forward, and will always march forward, at innumerable locations in the universe over countless eons of time. Detailed knowledge as to how and when those processes of Nature may have crossed from place to place in the Universe in the past may remain beyond our reach, but we should not allow that lack of knowledge to blind us into presuming that such crossings have never happened. Already in less than one hundred years of space travel we have evidence that such crossings are possible.
We turn now to Lucretius:
There is no end,
No limit to the cosmos, above, below,
Around, about, stretching on every side.
This I have proven, but the fact itself
Cries loud in proclamation, nature’s deep
Is luminous with proof. The universe
Is infinitely wide; its vastness holds
Innumerable seeds, beyond all count,
Beyond all possibility of number,
Flying along their everlasting ways.
So it must be unthinkable that our sky
And our round world are precious and unique
While all those other motes of matter flit
In idleness, achieve, accomplish nothing,
Especially since this world of ours was made
By natural process, as the atoms came
Together, willy-nilly, quite by chance,**
Quite casually and quite intentionless
Knocking against each other, massed, or spaced
So as to colander others through, and cause
Such combinations and conglomerates
As form the origin of mighty things,
Earth, sea and sky, and animals and men.
Face up to this, acknowledge it. I tell you
Over and over – out beyond our world
There are, elsewhere, other assemblages
Of matter, making other worlds. Oh, ours
Is not the only one in air’s embrace.
With infinite matter available, infinite space,
And infinite lack of any interference,
Things certainly ought to happen. If we have
More seeds, right now, than any man can count,
More than all men of all time past could reckon,
And if we have, in nature, the same power
To cast them anywhere at all, as once
They were cast here together, let’s admit –
We really have to – there are other worlds,
More than one race of men, and many kinds
Of animal generations.
Adding up all the sum, you’ll never find
One single thing completely different
From all the rest, alone, apart, unique,
Sole product, single specimen of its kind.
Look at the animals: is this not true
Of mountain-ranging species, and of men,
Of the silent schools of fish, of flying things?
Likewise you must admit that earth, sun, moon,
Ocean, and all the rest, are not unique,
But beyond reckoning or estimate.
Their term of life is definitely set
And so remains, their substance is of stuff
No less ephemeral than what we see
In the teeming multitudes of our own earth.
Lucretius – Book II – De Rerum Natura (Humphries translation)
** It is always important to keep in mind the limitations of “chance” in Epicureanism, as covered in A. A. Long’s “Chance and Natural Law in Epicureanism“