intension and extension, in logic, correlative words that indicate the reference of a term or concept: “intension” indicates the internal content of a term or concept that constitutes its formal definition; and “extension” indicates its range of applicability by naming the particular objects that it denotes. For instance, the intension of “ship” as a substantive is “vehicle for conveyance on water,” whereas its extension embraces such things as cargo ships, passenger ships, battleships, and sailing ships. The distinction between intension and extension is not the same as that between connotation and denotation.

Encyclopaedia Britannica, “intension and extension”

Pair of terms associated with J. S. Mill, and marking much the same distinction as the currently more usual intension/extension. The denotation of a singular term is the object to which it refers, and of a predicate the set of objects satisfying it. The connotation is the abstract meaning, or principle or condition whereby something is picked out as denoted by the term.

The Oxford Dictionary of Philosophy, “connotation/denotation”

While the Britannica entry is claiming to be about logic and the Oxford is about the Millian terms connotation and denotation, it still is confusing as to what the difference is between Mill’s logic and non-Mill’s logic, if indeed this is the point of difference.

Either way, we have varying definitions, which, ironically, is at the heart of the very problem of these terms — meaning.


Even if I talk about pegasus’ I only have a sense of pegasus, not a reference or a referent of pegasus.

The primary and secondary substance distinction

For me, the distinction between primary and secondary substance is an important one. Primary substance is about particular referents or objects. We may also think of primary substance as being undifferentiated tokens rather than classified or categorised tokens. Secondary substances are categorised types of tokens.

The symbol given to a primary substance is unique within a context. The symbol given to a secondary substance is not unique within a context.

Primary substances are without properties. Secondary substances are with properties.

The properties of a primary substance do not define the named primary substance. The properties of a secondary substance do define the named secondary substance.

The term of a primary substance is without meaning.

Ontological relations

A reality which exists independent of being perceived has ontological token relations but no conceptual, symbolic, semiotic or experiential relations.

Philosophical Tokenism

The philosophical position that there are only tokens in reality where types are realised as a mental process of classified tokens.


Everything, without exception, is physics.

Reality is now

There is only one reality – the present. The past is a memory and the future is a prediction.