When I consider the wonderful activity of the mind, so great a memory of what is past, and such a capacity of penetrating into the future: when I behold such a number of arts and sciences, and such a multitude of discoveries hence arising,--I believe and am firmly persuaded that a nature which contains so many things within itself cannot be mortal.
As I give thought to the matter, I find four causes for the apparent misery of old age; first, it withdraws us from active accomplishments; second, it renders the body less powerful; third, it deprives us of almost all forms of enjoyment; fourth, it stands not far from death.
Now in regard to trades and other means of livelihood, which ones are to be considered becoming to a gentleman and which ones are vulgar, we have been taught, in general, as follows. First, those means of livelihood are rejected as undesirable which incur people's ill-will, as those of tax-gatherers and usurers. Unbecoming to a gentleman, too, and vulgar are the means of livelihood of all hired workmen whom we pay for mere manual labour, not for artistic skill; for in their case the very wage they receive is a pledge of their slavery.
I speak of that learning which wakes us acquainted with the boundless extent of nature, and the universe, and which even while we remain in this world, discovers to us both heaven, earth, and sea.