Trust in the practice of rational deliberation is widespread and largely unquestioned. This paper uses recent work from business contexts to challenge the view that rational deliberation in a group improves decisions. Pressure to reach consensus can, in fact, lead to phenomena such as groupthink and to suppression of relevant data. Aggregation of individual decisions, rather than deliberation to a consensus, surprisingly, can produce better decisions than those of either group deliberation or individual expert judgment. I argue that dissent is (...) epistemically valuable, not because of the discussion it can provoke (Mill's and Longino's view about the benefit of dissent), but because dissenting positions often are associated with particular data or insights that would be lost in consensus formation. Social epistemologists can usefully pay attention to various methods of aggregation of individual opinion for their effectiveness at realizing epistemic goals. (shrink)

How sensitive should you be to the testimony of others? You saw the car that caused an accident going through traffic lights on the red; or so you thought. Should you revise your belief on discovering that the majority of bystanders, equally well-equipped, equally well-positioned and equally impartial, reported that it went through on the green? Or take another case. You believe that intelligent design is the best explanation for the order of the living universe. Should you revise that belief (...) on finding that most other people, or at least most who by your own lights are as intelligent, informed and impartial as yourself, believe that evolutionary theory offers the better account? Should you do this, in particular, if your own personal sense of where the evidence points – like your own vivid memory of the car going through on the red – remains firmly on the side of intelligent design? Assume, to take a third case, that there is a matter of fact about whether abortion is right or wrong. You believe that it is wrong, having a firm picture of it as an act on a par with murder. Should you revise that belief on discovering that among those whom you regard as equally intelligent, informed and impartial, most believe that abortion is not wrong, or at least not wrong in the way that murder is wrong? Should you do this, in particular, if your own personal sense of abortion remains unchanged; it still seems to you to be a grievous wrong? Should you put aside your own sense of things as mistaken, in the way you might put aside your imagined memory of the car going through on the red, and decide to go along with the majority view? (shrink)

The standard image of how consensus can be achieved is by pooling evidence and reducing if not eliminating disagreements. But rather than just pooling substantive evidence on a certain question, why not also take into account the formal, testimonial evidence provided by the fact that a majority of the group adopt a particular answer? Shouldn't we be reinforced by the discovery that we are on that majority side, and undermined by the discovery that we are not? Shouldn't this be so, (...) in particular, when Condorcet's jury theorem applies? It turns out not. There are serious problems attending any strategy of majoritarian deference. (shrink)

Polanyi’s theory of spontaneous order is set in historical context, analyzed, and compared to Friedrich Hayek’s version.