Basic income is argued for from premises that have almost nothing in common, which accounts for both its persistence and the incoherence of the coalition supporting it. One tradition treats it as the simplification of a welfare system whose conditionality is expensive to administer and humiliating to receive; another treats it as a dividend on commonly owned assets; a third, from the political right, treats it as a replacement for public services rather than a supplement to them. These are not versions of one proposal. A scheme that replaces disability payments with a flat sum is a different policy from one that adds to them, and the pilots conducted to date have overwhelmingly tested the second, while the fiscal arithmetic that makes the idea attractive at scale generally assumes the first.