Is a pearl beautiful? Yet consider, it is but sea water, and was once cast away in the bosom of the deep. Are gold and silver beautiful? Yet they were and are but dust and ashes. Are silken vestments beautiful? Yet they are nothing but the spinning of worms. This beauty is but in opinion, in human prejudice, not in the nature of the things. For that which possesses beauty from nature, need not any to point it out. If you see a coin of brass that is but gilded over, you admire it at first, fancying that it is gold; but when the cheat is shown to you by one who understands it, your wonder vanishes with the deceit.
The beauty therefore was not in the nature of the thing. Neither is it in silver; you may admire tin for silver, as you admired brass for gold, and you need some one to inform you what you should admire. Thus our eyes are not sufficient to discern the difference. It is not so with flowers, which are much more beautiful. If you see a rose, you need no one to inform you, you can of yourself distinguish an anemone, and a violet, or a lily, and every other flower. It is nothing therefore but prejudice.
And to show, that this destructive passion is but a prejudice; tell me, if the Emperor were pleased to ordain that silver should be of more value than gold, would you not transfer your love and admiration to the former? Thus we are everywhere under the influence of covetousness and opinion. And that it is so, and that a thing is valued for its rarity, and not for its nature, appears hence. The fruits that are held cheap among us are in high esteem among the Cappadocians, and among the Serians even more valuable than the most precious among us, from which country these garments are brought; and many such instances might be given in Arabia and India, where spices are produced, and where precious stones are found.
Such preference therefore is nothing but prejudice, and human opinion. We act not from judgment, but at random, and as accident determines. But let us recover from this intoxication, let us fix our view upon that which is truly beautiful, beautiful in its own nature, upon godliness and righteousness; that we may obtain the promised blessings, through the grace and lovingkindness of Jesus Christ our Lord, with whom, etc.
Source: Homilies on First Timothy (New Advent)