This is the second post in a series. The first post dealt with the importance of ‘experience’ in the sense of episodic memory, with consciousness supplying the moments making up an episode. Events that we are not conscious of simply do not get stored in episodic memory.

There is another type of memory which is not episodic, not autobiographical, carries no time and place information. It is usually called the semantic memory although it is not just about language. It stores facts, the sort of facts that you can state in natural language or some other representation (equations, musical scores, diagrams etc.). These are time-less, place-less, agent-less bits of understanding. This is memory of meanings, understandings, relationships, knowledge, ideas, concepts, and words with minimal context. The storage and retrieval processes of episodic and semantic memory appear to be separate with the exception that they are both declarative, or explicit, memory systems and therefore storage is from consciousness and retrieval is into consciousness.

What is the meaning of a word? Well, a word by itself does not have meaning. Meaning is gained by the relationships between words – they are defined in terms of other words/concepts.

Meaning is gained by how an entity takes part in the model of reality that we produce, by how it relates to other entities in the model. This model is what consciousness is derived from. Consciousness, in effect, brings the meaning from the model to the semantic memory and consciousness holds the meaning when it is retrieved from memory.

It is not clear whether semantic memory is stored as networks, matrices, hierarchies, chunks or some other embodiment. Whatever the structure, it supplies us with categories, contrasts, generalizations, and metaphoric analogs. Probably this structure is shared with other mammals, perhaps other vertebrates, but language has made it a powerful tool for humans by storing words so that they are retrievable into consciousness in ways that fit with our world model.

Language and other meaning systems are so important to us in communication with others and even within ourselves – their value cannot be overstated. The function of consciousness as a gateway to semantic memory is worth a great deal of biological cost.

In the three and a half years that I have been closely following scientific ideas about consciousness on the web, I have encountered a number of excellent ways to look at/ models of/ theories about consciousness. But I have not encountered anyone make a case for an intimate link between consciousness and declarative memory (except for the obvious definition of ‘declarative’ and ‘explicit’). I am surprised at this lack because the link seems so important in my view. If any readers know of such a argument having been made, I would appreciate a link to it.

There is more to come. The posts in this series to date:

Possible functions of consciousness 1 - leading edge of memory