The view that an agent knows that something is so when there is some appropriate causal connection between the fact that it is so, and the agent’s belief. The clearest example is direct perception, where the fact that there is a chair in the room causes my visual state of seeing that there is, and hence causes my knowing that there is. Difficulties include identifying the appropriate relation, extending the idea to less direct cases, especially those involving such apparently non-causal things as abstract objects, and accommodating examples where there may be a causal connection, but it would be most unreasonable of the agent to believe that there is. See also deviant causal chain.