Consider the following argument for school choice, based on an appeal to the virtues of the market: allowing parents some measure of choice over their particular children's education ultimately serves the interests of all children, because creating a market mechanism in state education will produce improvements through the same pressures that lead to greater efficiency and quality when markets are deployed in more familiar contexts. The argument fails, because it is committed to a principle of equal concern, which (after analysis) implies that a market in education is acceptable only if it is right to hold children disadvantaged by their parents' poor market choices substantively responsible for the fact. Since that claim is untenable, the market-based argument for school choice not only fails, but also turns out to rely on principles which in fact condemn the very policy it was supposed to support. (Contains 12 notes.)