The Routledge Handbook of Consciousness

Antti Revonsuo

is that we are trying to explain. For example, if we wish to explain perceptual consciousness in
wakefulness and dream experiences during sleep, we need to first have accurate descriptions of
the phenomenology of both perceptual and dream experiences. How do we visually experience
colors, objects, places, and faces in these two states?
Then we can start to fill in the different directions of explanation that “surround” the phe-
nomenon in the causal-mechanical network. The downward-looking (or constitutive) explanation
describes the lower-level nonconscious neural mechanisms that directly underlie consciousness
in the brain. We can also call them the constitutive mechanisms of consciousness. As “constitution”
implies ontological dependency, this set of neural mechanisms is bound to be a much narrower
subset of mechanisms than the mere neural correlates of consciousness. For example, the consti-
tutive mechanism of color experiences both during dreaming and wakefulness likely includes
the visual cortical area V4. When it is sufficiently activated, we have visual color experiences,
whether they are dreams, hallucinations, or visual perceptions. When area V4 is deactivated or
destroyed, experiences of color become impossible. Without V4, we can have achromatic visual
experiences only.
The upward-looking explanation describes the higher-level causal or functional role that con-
sciousness plays in the whole brain, the whole person, and especially in guiding behavior. For
example, color vision supports our ability to perceptually detect and discriminate from each
other differently colored visual objects such as traffic lights and signs, and quickly adjust our
behavior accordingly.
The backward-looking explanation moves backwards in time, tracing the causal chain of events
that resulted in or causally modulated consciousness. This explanation can look to the immedi-
ate past when explaining how a preceding stimulus resulted in a conscious experience, or to the
individual’s past, describing how conscious experience emerged and changed during individual

Upward-looking

explanation

Downward-looking

explanation

Person’s

behavior

Social

interaction

Backward-looking

explanation

Immediate stimulus

Individual development

Evolution

The Multilevel Framework

Neural correlates of consciousness (NCC)

Figure 14.1 The Multilevel Framework