The world's predominantly Muslim countries have long been underdevelop
ed. This paper classifies, critiques, and extends the mechanisms that
have been proposed as explanations for the pattern. One mechanism invo
lves the use of Islam to legitimize worldviews that served vested inte
rests. Another emphasizes religious obstacles to free thinking and inn
ovation. And still another focuses on communalist norms that dampened
incentives to develop capitalist economic institutions. None of these
explanations elucidates why groups without any stake in the impediment
s to growth failed to bring about major reforms. The missing element i
s the role of public discourse in keeping individuals from questioning
, even noticing, social inefficiencies.