The thinking system

...we may say that "mind" is immanent in those circuits of the brain which are complete within the brain. Or that mind is immanent in circuits which are complete within the system, brain plus body. Or, finally, that mind is immanent in the larger system - man plus environment.

In principle, if we desire to explain or understand the mental aspect of any biological event, we must take into account the system - that is, the network of closed circuits, within which that biological event is determined. But when we seek to explain the behavior of a man or any other organism, this "system" will usually not have the same limits of the "self" - as this term is commonly (or variously) understood.

...

...it is important to notice that there are multiple differences between the thinking system and the "self" as popularly conceived"
1) The system is not a transcendent entity as the "self" is commonly supposed to be.
2) The ideas are immanent in a network of causal pathways along which transforms of difference are conducted. The "ideas" of the system are in all cases at least binary in structure. They are not "impulses" but "information."
3) This network of pathways is not bounded with consciousness but extends to include the pathways of all unconscious mentation - both automatic and repressed, neural and hormonal.
4) The network is not bounded by the skin but includes all external pathways along which information can travel. It also included those effective differences which are immanent in the "objects" of such information. It includes the pathways of sound and light along which travel transforms of differences originally immanent in things and other people - and especially in our own actions.

Gregory Bateson, The Cybernetics of 'Self': A Theory of Alcoholism, in Steps to an Ecology of Mind, p317 & 319