in turn manipulated as propositions: event/statement “John hit Chris with the unicycle” is represented as proposition ‘P’. Also, features of particular objects may be characterized through attribute lists. ‘John’ as a singular object may have the attributes ‘plays guitar’, ‘juggles’, ‘eats a lot’, ‘rides a unicycle’ etc. Thus reference to ‘John’ identifies him as the object of thought in virtue of his having certain of these attributes. So in predicate calculus, if “John (F) has the property of being ‘rides a unicycle’ (x)” we may say salva veritate: (x)(Fx). These elements have been called semantic primitives or semantic markers/features. Each primitive may in turn form part of a propositional statement, which in turn could be represented by an abstract figure e.g. ‘P’. The primitives themselves play a crucial role in categorizing and classifying objects and concepts. The meaningful relations between ideas and concepts expressed between and within the propositions are in part dealt with through the general laws of inference. One of the most common of these is Modus Ponens Ponendum (MPP), which is a simple inference of relation between two objects, the latter supervening on the former (P-›Q). Thus if we have two propositions (P, Q) and we assume a law of inference that relates to them both (P-›Q), then if we have P we must necessarily have Q. Relations of causation and may be expressed in this fashion, i.e. one state (P) causing (-›) another (Q) So a purely formal characterization of the event (X) written above in natural language would be something like: P, Q (A) Q -› R (A) Q (A1) R (2,3 MPP) R -› S (A) S (4,5 MPP) References Logic Theory of mind Propositions