We divide the world into that which is subjective and internal and that which is objective and external. The boundary between the two acts like a container, which holds the former and places the latter outside. This container is what we know as the “self”. Among other things, it includes our thoughts, intentions, and habits, as well as our actual bodies. Except in altered states (see Altering Consciousness), all experiences we report include a sense of self, but most of the time the sense is unconscious. This “consciousness-with-self” is what we generally call “consciousness”. When the sense of self becomes conscious, we talk of being “self-conscious”.

Representing the self

The physical self is encoded in various “body maps” onto which experiences are charted. The “mental” self is more fragile and is strongly connected with the ability to retrieve personal memories.

Agency is our sense of control over our actions. We feel that our conscious thoughts dictate what we do, but this appears to be incorrect. A famous experiment by Benjamin Libet (see Packets of time) revealed that a person’s brain starts to plan and execute a movement unconsciously, before the person has consciously decided to do it. This is often interpreted to show that our sense of agency and of making “decisions” is illusory. The sense of agency we experience may actually have evolved primarily to give us early warning not of our own actions, but of the actions of others. Because we feel ourselves to be agents, we also intuit agency in others, and thus think we know their intentions and can predict what they will do.

Unconscious reflex

We have no sense of agency about a knee-jerk reaction because it occurs without us consciously “willing” it.

The evolution of agency

Awareness of what we are about to do may have arisen late in our evolution, once the action-planning part of our brain had connected to the areas that support consciousness.

Seeing intention behind actions

Our tendency to see intention leads us to visualize it even in the behavior of nonsentient objects. Read as a cartoon strip, the pictures on the left suggest a chase in which the smaller objects “hide” and “escape” from the largest one.

The brain holds various “body maps” – internal representations of the physical self. The earliest, most basic map to emerge tells us where our body ends and the rest of the world begins. A more developed body “atlas” enables us to know our spatial location in the world. Normally, the internal maps and the body itself are closely matched, but it is possible for them to be askew. If a person loses a limb, for example, they may develop what is known as a phantom limb—a feeling that they have a limb that, in fact, no longer exists (see The Sixth Sense). People can also be tricked into “owning” a limb or even a body that is not actually theirs.

Infant body maps

Babies probably do not distinguish between their body and external objects until their body maps start to take in information from the world.

The collective unconscious

Carl Jung (1875–1961) was a Swiss psychiatrist who developed the idea of the collective unconscious—a part of the unconscious mind shared by everyone as a product of ancestry. He thought it included “archetypes” (innate, universal concepts) such as the mother, God, hero and so on, and that we detect their influences in the form of myths, symbols, and instinct. Presumably he saw the collective unconscious as a sort of “folk memory”, embodied in the structure of the brain.

Out-of-body experiences

Out-of-body experiences (OBEs) occur when the internal representation of the body is out of kilter with the real body. This happens all the time in dreams, but when it happens during wakefulness it may be interpreted as a supernatural event. OBEs typically occur as you wake up, before the brain has properly reconnected with the external world .

Near-death experiences

OBEs are often accompanied by feelings of ecstasy, and they are a central feature of many so-called “near-death experiences.”