Virtue

White is a colour. It is not a mere absence of colour; it is a shining and affirmative thing, as fierce as red, as definite as black. When, so to speak, your pencil grows red-hot, it draws roses; when it grows white-hot, it draws stars. And one of the two or three defiant verities of the best religious morality, of real Christianity, for example, is exactly this same thing; the chief assertion of religious morality is that white is a colour. Virtue is not the absence of vices or the avoidance of moral dangers; virtue is a vivid and separate thing, like pain or a particular smell. Mercy does not mean not being cruel or sparing people revenge or punishment; it means a plain and positive thing like the sun, which one has either seen or not seen. Chastity does not mean abstention from sexual wrong; it means something flaming, like Joan of Arc. (GK Chesterton "A Piece of Chalk," from Tremendous Trifles. 1909)

This is something I learned early from CS Lewis - and there are those who will tell you that everything in Lewis has its origin in Chesterton - that virtue is a positive thing, not an absence. It was a gripping and inspiring idea, coming from a college mentality where chastity, or a virtuous woman was defined almost entirely in terms of whether or not she was technically a virgin or not. And it was an age where virginity was often entirely technical, especially for women. Women resented this bitterly, even as they were the strictest enforcers, because that's what human beings are like.

Yet certainly, it's not just sex, even though that was the morality most on the mind of a man in his 20's. GKC points to Mercy, above, and we could say much the same about Justice, or Temperance. We occasionally get that far with the cardinal virtues.  It is even more true of the Theological Virtues.  Faith is not a matter of screwing yourself up to not doubt, not in any corner of your mind, but something that involves marching forward and doing, not even much bothering whether any residual doubt lingers. Hope is not just putting on a good front and not saying anything weak, it is a positive desire for the Beatific Vision. And Charity/Love we readily see, is not just avoiding being stingy or mean, but a positive desire for the good of another.