Philosophy of Death & Time
Why Killing Is Wrong: The Answer Is Stranger Than You Think
Most arguments against killing turn out to be arguments against something else entirely.
The Idea
The obvious answer to why killing is wrong — 'because it ends a life' — collapses almost immediately under pressure. Animals end lives all the time; we don't call them murderers. So the wrongness must be something specific to what killing does to persons. But what, exactly? The most influential philosophical answer of the last half-century belongs to Don Marquis, who argued in 1989 that killing is wrong because it deprives the victim of a 'future like ours' — a future of experiences, relationships, projects, and pleasures they would otherwise have had. The harm isn't just the moment of death; it's everything that gets cancelled. This is called the deprivation account. What makes this view genuinely unsettling is its rigour. It explains why killing a healthy 30-year-old feels more catastrophic than killing a 90-year-old in decline — not because one life is worth more, but because more future is at stake. It also explains why we don't typically think of contraception as killing: a sperm or egg has no ongoing projects, no anticipations, no continuous self whose future gets stolen. But the deprivation account creates problems too. Does it imply that death is always a harm, even a peaceful death at extreme old age? And what about beings — certain animals, people with severe dementia — who arguably have futures but lack the kind of self-awareness that generates anticipations? The cleaner the theory, the sharper the edges it leaves exposed.
In the World
In 1972, a philosopher named Peter Singer published an essay arguing that our intuitions about killing are radically inconsistent — and he meant that as a diagnosis, not a comfort. If the wrongness of killing rests on depriving a being of future experience, Singer pressed, then our treatment of non-human animals becomes morally incoherent. A pig, he argued, has a richer future-oriented mental life than a newborn human infant, yet we grant the infant absolute protection and the pig almost none. Singer wasn't being provocative for sport. He was pointing to the gap between our stated moral principles and our actual practices. The philosopher Jeff McMahan later refined this into a detailed account of how the 'time-relative interests' of a being — how strongly its present self is psychologically connected to its future self — should determine how bad its death is. A being with no long-term memories, no plans, no continuous narrative self, has weaker time-relative interests, and therefore less to lose. This framework disturbed people because it seemed to rank lives, which felt monstrous. But McMahan's counter was that we already rank lives implicitly — in triage decisions, in how we weigh the death of a child against the death of an elderly person — and that philosophy's job is to make those implicit rankings honest, not to abolish them. Whether or not you accept his conclusions, the framework forces a question most of us prefer not to ask: on what grounds, exactly, do we draw the lines we draw?
Why It Matters
Most of us go through life with a rough moral intuition that killing is wrong without ever examining the architecture underneath it. That's fine for ordinary life. But the places where ethics actually gets difficult — end-of-life care, animal agriculture, war, capital punishment, abortion — are precisely the places where 'it just feels wrong' is not enough to navigate by. Understanding the deprivation account, even without accepting it entirely, gives you something more useful than a firm answer: it gives you a better question. Instead of asking 'is this killing wrong?' you learn to ask 'what is the nature and extent of what is being lost, and by whom?' That reframe doesn't resolve hard cases — philosophers have been arguing about it for decades — but it makes you harder to manipulate by appeals to emotion or reflex, and more honest about the trade-offs embedded in positions you already hold. The goal isn't to become colder. It's to become more precise about what you actually care about and why — which, in the end, tends to make the caring more serious, not less.
A Question to Ponder
When you think about what makes killing wrong, are you really thinking about death itself — or about the loss of everything that would have come after?
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