by Charlie Huenemann
At the beginning of book three of his Treatise on Human Nature, David Hume argues that justice is something we invent. In a word, justice is unnatural. It isn't something we just see in the world, since we only ever see what is, and nothing in what we see tells us how things ought to be. Neither does justice come from some inner, natural feeling, if by “natural” we mean the hard-wired, immediate pleasures and pains that we can't help but have. No; to have any sense of justice, we have to be taught to have it. We have to be trained by others to feel a particular kind of pleasure in seeing fair treatment being done. Our parents have to show us how to be fair, and encourage us in whatever ways they can to get us to want fairness, until it starts to seem natural to us.
Parents train their children in this way because, somewhere along the way, our ancestors figured out – probably the hard way – that respecting and honoring fairness eventually leads to the kind of life where we can live safely, raise families, and keep property. Justice works. And so these ancestors taught their children to be fair, and they taught their children, and so today do we. “In a little time, custom and habit operating on the tender minds of children, makes them sensible of the advantages, which they may reap from society, as well as fashions them by degrees for it, by rubbing off those rough corners and untoward affections, which prevent their coalition”. We become shaped by our early experiences to take some pleasure in a sense of justice – and a good thing, that.
Hume argues that this early and artificial shaping has to be in place well before promises can have any hold over us. Promises come about because, at some point, the affairs of daily life present us with circumstances where an exchange of this for that can't happen right away. “Your corn is ripe to-day; mine will be so to-morrow. 'Tis profitable for us both, that I shou'd labour with you to-day, and that you shou'd aid me tomorrow”. At this point, a promise would come in handy. So we invent special words and signs that constitute a promise. But there is no reality to this human invention, apart from all of us agreeing to treat it as a real thing, out of the interest in justice we have been shaped to have.
