 An internal cause is a causal chain of events such that each link in the chain is either a belief, a reason (construed to include perceptual and sensation states, as well as beliefs), or an inference. One’s beliefs, reasons, and inferences collectively constitute what Korcz calls one’s cognitive structure. The various sorts of causes mentioned in (a)(i) are required to be internal to S’s cognitive structure so as to avoid problems with deviant causal chains. Deviant causal chains seem to occur when the chain of causal events from a putative reason to a belief veers outside the persons cognitive structure. For instance, in Plantinga’s example of Sylvia discussed above, the causal chain of events includes the event of dropping a cup of tea, and this event is not one which occurs within the person’s cognitive structure. However, Korcz acknowledges that this is not a fully satisfactory solution to the problem of deviant causal chains, given the difficulties of specifying exactly which events are internal to one’s cognitive system in the appropriate way.