Group Knowledge

There is knowledge in groups or communities, e.g. in the
scientific community, that such and such is the case, and
that in some cases groups as groups know; and in all
these cases there must be or have been actual knowers.
Accordingly, there is knowledge available in social groups,
and this knowledge can be "picked up� and had by
individual members as knowledge. My main concern in this
paper is to give an account of group beliefs and knowledge
in the sense that the group members as a group believe or
know something. A central case here is normatively
binding group belief and knowledge. In such a case the
group is obligated to reason and act on the truth of the
content of the belief in question. I will assume that a group
cannot know unless its members or at least some of them
know the item in question. The general ground for this
assumption is that group properties supervene on their
members' relevant properties (see Tuomela 1995 Chapter
6, for a discussion). A group's normatively binding belief
concerning a topic will accordingly depend on its members,
beliefs, indeed we-mode "acceptance� beliefs, about the
topic and on their relevant "interconnections" concerning it.
We-mode acceptance belief centrally involves the idea of
functioning fully as a group member (see Tuomela 2002a,
2003a for the we-mode). A member"s private or I-mode
beliefs may differ from his relevant we-mode beliefs.