Russell on physicists and the search for causes

Russell on physicists and the search for causes: I think -- there seems to me a certain unwarrantable extension here; the physicist looks for causes; that does not necessarily imply that there are causes everywhere. A man may look for gold without assuming that there is gold everywhere; if he finds gold, well and good, if he doesn't he's had bad luck. The same is true when the physicists look for causes.

This links to the Russell-Copleston debate. Before there was William Lane Craig, there was the Russell-Copleston debate.