Book V:

In which, having been deceived by the Pirate Queen, the two Romans and their adopted children languish in captivity while seeking escape.

Mortals, vain as they are, and ingenious in deceiving themselves, calculate in the same way as the Thracians, who, according to their experience of each day, deposit in an urn a black or a white pebble; at the close of their life, these pebbles are separated, and from the relative number of each kind, they form their conclusions.

But really, may not that very day that has been complimented with a white pebble, have contained in itself the germ of some misfortune?

How many a man has got into trouble by the very power which has been bestowed upon him?

How many have been brought to ruin and plunged into the deepest misery by their own blessings? or rather, by what have been looked upon too fondly as blessings, for the hour during which they were in the full enjoyment of them.

But most true it is, that it is the day after, that is the judge of the day before; and after all, it is only the last day that is to set its stamp on the whole; the consequence is, that we can put our trust in none of them. And then, too, is it not the fact that the blessings of life would not be equal to its evils, even though they were equal in number? For what pleasure is there that can compensate for the slightest grief?

Alas! what a vain and unreasonable task we impose upon ourselves! We trouble ourselves with counting the number of days, when it is their weight that ought to be taken into consideration.

Pliny The Elder

Natural History

Vol II Book VII Chapter 41