Lucretius, De Rerum Natura
William Ellery Leonard, Ed.

     Again, why is't there goes
Impetuous rage with lion's breed morose,
And cunning with foxes, and to deer why given
The ancestral fear and tendency to flee,
And why in short do all the rest of traits
Engender from the very start of life
In the members and mentality, if not
Because one certain power of mind that came
From its own seed and breed waxes the same
Along with all the body? But were mind
Immortal, were it wont to change its bodies,
How topsy-turvy would earth's creatures act!
The Hyrcan hound would flee the onset oft
Of antlered stag, the scurrying hawk would quake
Along the winds of air at the coming dove,
And men would dote, and savage beasts be wise;
For false the reasoning of those that say
Immortal mind is changed by change of body-
For what is changed dissolves, and therefore dies.
For parts are re-disposed and leave their order;
Wherefore they must be also capable
Of dissolution through the frame at last,
That they along with body perish all.
But should some say that always souls of men
Go into human bodies, I will ask:
How can a wise become a dullard soul?
And why is never a child's a prudent soul?
And the mare's filly why not trained so well
As sturdy strength of steed? We may be sure
They'll take their refuge in the thought that mind
Becomes a weakling in a weakling frame.
Yet be this so, 'tis needful to confess
The soul but mortal, since, so altered now
Throughout the frame, it loses the life and sense
It had before. Or how can mind wax strong
Coequally with body and attain
The craved flower of life, unless it be
The body's colleague in its origins?
Or what's the purport of its going forth
From aged limbs?- fears it, perhaps, to stay,
Pent in a crumbled body? Or lest its house,
Outworn by venerable length of days,
May topple down upon it? But indeed
For an immortal perils are there none.