These concerns are a different kind than technology-based objections to killer robots. For instance, critics point out that artificial intelligence still can’t reliably distinguish between a lawful target (such as an enemy combatant with a gun) and an unlawful one (such as a civilian with an ice-cream cone), as demanded by the laws of war. Technology limitations, like this one and others, are possibly solvable over time. But if lethal autonomous weapons are truly an assault on human rights, that’s a philosophical challenge that can’t just be solved with better science and engineering. So it’s worth focusing on human rights as some of the most persistent problems for the killer robots, and I’ll keep that separate from technical issues to not confuse an already-complex debate.

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What’s objectionable to many about lethal autonomous weapons systems is that, even if the weapons aim only at lawful targets, they seem to violate a basic right to life. This claim is puzzling at first, since killing is so commonplace and permitted in war. If you’re a combatant, you are legally liable to be killed at any time; so it’s unclear that there’s a right to life at all.

But what we mean is that, in armed conflicts, a right to life means a right not to be killed arbitrarily, unaccountably, or otherwise inhumanely. To better understand the claim, a right to life can be thought of as a right to human dignity. Human dignity is arguably more basic than a right to life, which can be more easily forfeited or trumped. For instance, even lawful executions should be humane in civilized society.

Therefore, I will focus on dignity as a way to understand the right to life in this debate, though the two are more distinct in other contexts. Indeed, critics of killer robots also argue that automated killing violates a right to human dignity.

So, what is human dignity? Unfortunately, the concept is vague; there’s not much consensus on an answer. We should note that, in many cases, a lack of human dignity does not make something illegal. People do undignified and shameful things all the time legally, such as lying and adultery. And what’s so dignified about going to the toilet or having sex? Sometimes, we’re happy to trade dignity for security, such as allowing airport personnel to search our bodies, as if we were criminal suspects. This is to say that our relationship status with dignity is complicated.

As it relates to killer machines specifically, human dignity is said to be about accountability, remedy, and respect. And these are capabilities that mere machines don’t seem to have, as some experts point out.

These inabilities are related to a lack of meaningful human control. Without that control, it’s unclear who or what is responsible for wrongful targeting and errors. Without being able to identify responsible parties, there’s no one to demand remedy from or compensation for wrongful injury or death. And making decisions to kill another human being—one of the most profoundly serious decisions we can ever make—demands respect in the form of reflection and meaning that machines cannot give.