However, I have not been happy about the actual names, which are partly uninformative and, as I now have come to feel, somewhat inaccurate.
Original Participation is not truly a participation in reality and creation because it is a passive and unconscious state. The Consciousness Soul (this term comes from Steiner, rather than Barfield) is simply uninformative. And the term 'Final' in Final Participation is not descriptive - but rather it informs us that this is the qualitative mode of divine consciousness, and therefore no further evolution (except quantitatively) is possible.
So I will be trying-out a new set of terms: Original Immersion, Detached Agency and Agent Participation.
Original Immersion (this was OP)
This refers to the original state of consciousness for Man. Original in the sense of its being both the mode of consciousness of young children, and also of early tribal man - foragers/ hunter-gatherers.
It is a state of passive and unconscious immersion in reality - 'animistic', regarding the world as alive and conscious.
There is little in the way of a separate self - therefore little in the way of agency. The content of thought is mostly caused.
The child's thinking is therefore essentially a consequence, rather than being internally-generated. So, the child is not 'creative' - does not originate or generate thinking.
It is also something of a 'twilight' state, in some ways intermediate between the awake and asleep state of modern Western adults - and a modern adult can experience Original Immersion in some altered states of consciousness such as trances, delirium and certain 'drugged' states and psychosis (for example).
Detached Agency (this was CS)
This refers to the characteristic state of consciousness of an awake, alert, modern Western Man.
Our self is detached from the world, observing it through the senses; and we are strongly aware of this separate self and its agency in thinking.
The evolutionary step is in agency - thinking becomes a primary cause, self-caused: thinking emerges-from the self intrinsically. Thinking need not be a consequence of external factors.
With detached agency, Man becomes creative - originates thinking. However, this thinking is at the level of ideas and imaginations. These thought must be translated into the external world - by 'actions'. And actions are known only via sensory perceptions.
Therefore in the stage of the process is indirect. Thinking does Not participate in reality
Initially the self may feel cut-off, and doubt the reality of the world ('solipsism'); and ultimately - by inference - may doubt its own reality.
The agent self experiences the world as perceptual/ sensory input that is made-sense-of by reasoning - i.e. a matter of facts and theories. Thus is it is literalistic, scientistic, materialist and reductionist. Reality is dead/ not-alive.
There is no experience of objective meaning nor purpose nor relationships: these are just theories.
Subjectivity is the dominant experience; objectivity is conceptualised sensation.
Agent Participation (this was FP)
The thinking of the creative and agent self participates in reality - directly. This is the divine mode of thinking.
That is, thinking is real, and reality is thought - and there is a unity, no separation - therefore reality is changed (expanded) by thinking.
So, with Agent Participation, the Man directly knows reality - not indirectly via senses and reason or facts and theories. Direct knowing means there is no mediation, which means that there is unity.
For a divinity, reality is 'made' by thought; and known directly because the reality is the divine thought.
However, Agent Participation is partial, from a perspective. Thus some of reality is known directly, and creativity has also a limited scope.
Thus, in Agent Participation, everything than can be thought is real - but only some things can be thought. Everything than can be thought is known - only some things can be thought.
And in Agent Participation with respect to creativity: everything that can be thought is original, uncaused and self-generated (although, naturally, it may and probably will use the existing knowledge of that self).
Everything that can be thought is participated-in, and therefore this thinking is directly creative (without mediation) - but only some things can be thought and only some kinds of creativity are possible.
The idea is that scheme describes the (ideal) development of a child to an adult who is divine - being a son or daughter of God: Original Imersion being young childhood, transforming to Detached Agecy at Adolescence. Most modern men are arrested at this adolescence of consciousness, but almost all will have periods of Agent Participation - even though they may be brief, feeble, and not taken seriously.
The scheme also describes the development of human society from earliest Man through modern Man to the divinely destined future of man. And it describes states of consciousness which we each may move-between - even during one day of our lives.
But the main 'lesson' or value of these categories is that Agent Participation is what we ought to - and need to aim at in our lives - as indeed the primary aim of a Christian.
In other words, these categories are a description of spiritual progression, theosis, sanctification or divinisation. Therefore, Agent Participation cannot be achieved except insofar as a person is Good and motivated by Love.
Because to participate-in creation is to participate in the loving work of God, it is the most profound alliance-with God.
Hence the absolute nature of the first and second commandments: Love of God, and of Neighbour (our neighbour being our co-participant). Only thus may creation proceed.
Note: These three states are - strictly speaking - 'polarities' in the sense that although they can be objectively distinguished (as above) they cannot be fully separated or detached one from another. For example, even a young child is not fully without agency or creativity; and certainly some hunter gatherers display these traits at some times.
In other words, these are extremes or emphases of a unitary process of human consciousness. Any categorical scheme, when applied to a process, can only result in such polarities - because ultimately the unity cannot be divided without destruction of its nature.