Therefore the wise man will lose nothing which he is able to regard as a loss; for the only possession he has is virtue, and of this he can never be robbed.
- Seneca, On Firmness (Basore translation)
Can something that we cannot guard, that can be snatched away from us at any moment, truly be considered our own? Can a supposed possession be "possessed" by us if we no longer have it? To call something our own, it must be fully, not partially, ours. We must be able to protect to always, and possess it always. If not, it is like a thing on loan.
The wise man loses nothing. Nothing can be stolen or even slip away from him. His possessions are permanently his own. And this is so because the wise man has a proper understanding of what his possessions are.
There are things under our control and there are things not under our control. And the things that are under our control, by definition, are always under our control.
The wise man is wise precisely because he has recognized that this thing under his control is Virtue, and Virtue alone. And what a glorious array of possessions Virtue contains! How rich the wise man is in goods! Courage, Temperance, Justice, Wisdom, and a whole host of other treasures are his for as long as he chooses to possess them. Neither Man, nor Fate, nor Chance, nor even God can take away what is his.
The wise man will lose nothing, because he can lose nothing.