The meaning of concepts is relational and multidimensional, and should not be understood in terms
of some thing that constitutes the content of a concept. For example, the concept chair construed as a
pattern of neural activation has meaning in part because that pattern has causal correlations with the
world through various kinds of perceptual and motor interactions. Chairs have causal effects on
neural activity through sensory processes, and neural activity has causal effects on chairs through
brains' ability to direct bodily movements. But it is equally important that the pattern has correlations
with other neural patterns, some of which may have little direct connection with perception. For
example, it is part of the meaning of the concept of a chair that it is a kind of furniture and can be
bought in stores.
In chapter 3, I argued for the conceptual shift away from thinking of minds as things to thinking of
them as relational processes. Similarly, a difficult but explanatorily valuable part of the Brain
Revolution is its shift away from thinking of concepts and their meaning as entities and toward
understanding them as processes with relations along multiple dimensions, involving both the world
and other concepts.
We will see in chapter 7 that the meaning of life is also multidimensional, concerning relations
between persons and various aspects of their lives, especially love, work, and play. Because the
meaning of a concept does not depend simply on perceptual experience, concepts can constitute
knowledge about things that our senses are too crude to perceive. Let us now look at how we can
have knowledge about things that goes well beyond our rather limited sensory capacities.