On first read this sounds almost stern — even a little cold. Is Lewis telling us not to love things deeply, in case they're taken away? Look closer and it's the opposite: it's a warning born of taking love and loss extremely seriously.

The line comes from The Four Loves, Lewis's study of the different kinds of human affection. He knew profound grief — he lost his mother as a boy, and later his wife to cancer, an experience that produced one of the most unflinching books ever written about mourning. So this isn't detachment from someone who's never risked anything. It's hard-won counsel about where you place the full weight of your happiness.

The distinction he's drawing is subtle but freeing. Loving people and things that can be lost is not the mistake — that's simply what it is to be human, and Lewis championed it. The mistake is letting your entire sense of wellbeing rest on a single fragile thing, so that its loss would leave you with nothing at all. When happiness is balanced only on one person, one job, one outcome, we don't actually love that thing more freely — we love it anxiously, clutching, terrified of the loss we've made total.

Read that way, the advice is really an invitation to build happiness on a wider footing: on several loves, on meaning, on things that can't simply be taken in an afternoon. Not so you'll care less when you lose something, but so that loss, when it comes — and Lewis knew it comes — doesn't take the whole of you with it. It's a quietly protective kind of wisdom, offered by someone who understood exactly what's at stake.