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Impossible attempts were first officially recognized as non-criminal in 1864, the idea being that a person whose anti-social bent poses no appreciable risk of harm is no criminal.

To reassure myself the subject doesn’t “smell of the lamp,” I tapped “impossibility” into Westlaw, which designated nearly 1500 criminal cases as on point, 900 or so more recent than 1999. Impossible attempts thus turn out to be not merely a professorial hobby horse, but instead, expressive of a non-trivial tension between risk-taking and harm-causing within the very real world of criminal litigation.

Although it is now hornbook that impossible attempts are punishable as crimes, there remains a sense of a non-trivial difference between failing at larceny by picking the empty pocket of a passerby on a sidewalk and by picking the empty pocket of a mannequin in a department store. What remains up in the air is what accounts for that difference. Here I hope to decode the impossibility defense by “hounding down the minutiae” of what it means to make a mistake. I am certainly not the first to insist that the impossibility defense lives on. I am, however, the first to base such a claim on the grammar or criteria of mistakes, which can get us closer to the bottom of what makes attempts impossible and why it matters.

Extant impossibility cases and scholarship take mistakes as a given. But what is a mistake? Is the answer too obvious to mention? Within the stock hypotheticals of impossible attempts, a man shoots a tree stump or a corpse, each mistaken for a live person, or administers a live person an innocuous substance mistaken for poison. These stick-figure hypotheticals pose whether attempted murder has occurred. But because it is stipulated that each action owes to mistake, we are told so little about what happened that of course the question is hard to answer. Any chance of making sense of the hypotheticals is stymied by an absence both of facts and any concern for what can count as a mistake. My contribution here to the considerable work of others is therefore to locate the impossibility defense within an actual context of human action and concern.

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