The idea is that our consciousness - which can be understood as our conscious will
This 'evolved' or developmentally-unfolded through human history, and an analogous development typically happens through our modern life - at least in the The West.
The conscious will - which is where we feel our-selves to be located, the 'I' or ego that looks-out on the world - can be regarded as an intermediary between the body and the perceptions on the outside, and our real-divine self which is on the 'inside'.
Although actually the real-self is not tied to the body; yet incarnation means that in a significant sense the real-self is located in time and space. Thus incarnation is what gives us greater freedom and an unique perspective.
Without incarnation the real-self is not distinctly separated-from the divine will and thought; and is less of an agent, less free. But with a developed conscious will that comes between our perceptions and our real-self; we have the ability to shift, direct and focus attention.
This means that our conscious will can choose to present different phenomena, for consideration by the real-self. The conscious will can (in effect) move our bodies to a new environment, can choose to focus attention on particular aspects of the perceived environment, or can retrieve memories - and these are then brought to the attention of the real-self.
The conscious will can focus on perceptions, on inner body states, on memories - or it can focus on the real-self - and on the thoughts that are 'emerging' from the real-self.
By this model; primary thinking is what happens when the conscious-will is attending to the real-self; and the conscious-will is (in a sense) subordinating-itself to the real self.
So that, for example, the conscious-will moves the body to a different place, alters that which is perceived (by seeking particular kinds of experience), and shifts attention in line with the requirements of the real-self.
This is to live in Final Participation; led by the real (and divine) self, and with intuition (= primary thinking) leading the conscious will.
But in Final Participation always there is (and must be) the conscious choice about where to direct the conscious-will, moment-by-moment.
So, in Final Participation; conscious choice is voluntarily aligned-with the divine; it is aligned via the real self which is that which is divine within us.