Intentionality and causality in John Searle

Intentionality, as Brentano originally introduced the term in modern philosophy, was meant to provide a distinctive characteristic definitively separating the mental from the physical.(1) Mental states have an intrinsic relationship to an object, to that which they are "about." Physical entities just are what they are, they cannot, by their very essence, refer to anything, they have no "outreach", as one might put it. Mental states have, as it were, an incomplete essence, they cannot exist at all unless they are completed by something other than themselves, their object. Brentano's position is opposed to all theories which represent the mental as only extrinsically related to the world, that is, to all theories in which mental states are themselves self-sufficient for their own existence and only secondarily relate to the world by means of something external to their nature, e.g., neurological causation, divine intervention, or pre-established harmony. In these later cases, any mental act whatsoever could be related to any object, or indeed to none, for the relation is external to the nature of the act, it is superimposed on it by outside forces. Brentano's point is that a mental act has, by its very essence, an Intentional object without which it would not be a mental act. It would therefore appear that since causality is an external relationship which could in principle relate any two things regardless of their nature, the Intentional relation between an act and its object cannot be a causal relation.