The United States wants to get a man on the moon before the decade is out. The jury believes the defendant is guilty. The School of Physics plans a series of groundbreaking experiments. These sorts of statements are common, apparently true, and peculiar. They are peculiar because, taken at face value, they ascribe mental states (desires, beliefs, plans) not to individual human beings, but to groups.
What does the world have to be like, in order for these claims to be true? And are they true at all, or just loose talk? The hypothesis of this project is that they can be true, and true in exactly the same sense that you or I have beliefs or desires. Further: that they are true in virtue of groups acting in ways that, so-interpreted, are most rational. That’s significant, because it means that groups like corporations, committees or states can in principle meet the conditions for ethical responsibility. But the project also argues that the conditions under which we ascribe mental states to groups are often inadequate. It’s not enough that a majority or supermajority of voters support a proposition, for example, for that to be the will of the population. The group must have the right structure, and must manifest its alleged beliefs and desires in action over time, in order for it to truly have mental states.
The overall objectives of this project are, first, to construct a unified account of belief and desire that covers both the case of individual human beings, and groups. It will do this by looking at what patterns of belief/desires would fit with (make most rational sense of) the choices and evidence of the human or group. Accordingly, the second objective is to examine the notion of “group action” and “group evidence” and relate them to the individual case. A third objective is to spell out what “making most rational sense” means. The fourth objective is to use this machinery to lay down conditions under which ascribing groups beliefs and desires is literally true, and conditions under which it really is just a kind of dramatic metaphor---but also to spell out why even when metaphorical, it can be useful.
