Historians generally see ideas as the product of circumstances, looking beyond the idea to the external factor which influenced its acceptance. Behind an idea there are acknowledged or, more commonly, unacknowledged clusters of assumptions shared by a social group. Although these clusters influence thoughts, they cannot be traced as direct causal agents. In the connection between situations and ideas, how the situation is perceived is more important than what is objectively true. Rough causal laws can be outlined by correlating types of social conditions with types of states of mind. Sets of ideas point beyond themselves to the background against which they were framed.