Maybe, as one of my graduate students suggested, mind is more like a liquid that flows through and between things than it is a light projected onto and reflecting off of their surfaces (bracketing for now the fact that light also behaves like a fluid). This is an imaginative way of describing the difference between Whitehead’s two modes of perception: the water-like emotional transmission of causal efficacy and the light-like spatial extension of presentational immediacy.
Whitehead differs from Aristotle only in that his teloi continue to creatively evolve beyond established forms of order, while Aristotle’s telic forms (while individually dynamic) are eternally determined on the levels of species and genera.
Whitehead leaves us with some ambiguities about the spatiotemporal boundary around individual actual occasions, or around the final satisfaction of an occasion. How do we draw such boundaries without severing individual occasions from relational processes that generate them? Whitehead will try to tell us how this can be done in Part IV on the “coordinate analysis” of extension. But he admits from the get go that this is an exercise in abstraction, and that concretely speaking the experience of each actual occasion is in a sense boundless: it includes in its concrescence the entirety of the universe in its actualized and potential forms. But in another just as important sense, an occasion attains its individual satisfaction by collapsing the real potentiality of the given world into a uniquely actual perspective to be added to the universe.
If there is any sense to the question of the boundary of an actual occasion, its meaning must lie in the experiential intuition of “perpetual perishing.” Whitehead is asking us to take an imaginative leap in applying his language to our experience. What is this “perpetual perishing”? For Whitehead, it represents the boundary between subjective immediacy and objective immortality. It is the boundary between who “I” am right now and the “me” I was five seconds ago. I am not the same entity (“no thinker thinks twice”), and yet I feel a certain intimate society with my own past. The process of perpetual perishing is the pulse of the cosmic heart, pumping dead facts from the past back into present immediacy of feeling. So an actual occasion’s boundary, its perishing, is also a pathway into a new life, that of another occasion. Boundaries are also lines of transmission or descent.
The image we have of an enduring object like a gray stone as “passive stuff with permanent attributes, enduring without differentiation…” is actually an instance of overly abstract but still convenient symbolic reference. Conceiving of a grey stone as an enduring substance is an abstract notion that from Whitehead’s processual point of view can be said to result from a confused synthesis between causal efficacy (contributing the stone’s endurance through time) and presentational immediacy (contributing its seemingly permanent attribute of grayness).
Presentational immediacy grants us perception of the grey stone as a geometrically projected patch of color as it exists right now over there. Causal efficacy grants us perception of the grey stone’s weight when we pick it up in our hand, of the way this weight influences the muscle fibers and nerve endings in our arm as it is transmitted to the presiding occasions of the brain.
Causal efficacy is the feeling of our eyes blinking when we pull back the curtains and the sunlight floods onto our face. Presentational immediacy is the view of the meadow out the window after our eyes adjust.
It could be that our view of the meadow is really just a high definition television screen set inside the window frame. This would be “delusive” in Whitehead’s sense, because we are not in fact seeing what we think we are: the cause of our seeing the meadow is a bunch of pixels on a screen and not sunlight reflecting off of grass. We directly perceive the digital meadow and yet are deceived by it.
Colin Wilson’s translation of causal efficacy as “meaning perception” is almost right, since it is true that presentational immediacy gives us no hints about the past or future but only grants us an instantaneous impression of the contemporary world, while causal efficacy grants us some sense of where things are coming from and where they are going. But strictly speaking, meaning comes from symbolic reference, not from causal efficacy alone, which Whitehead says is a source of only rather vague information about the causal vectors of the surrounding environment. Strictly speaking, symbolic reference, by relating causal vector-feelings to presented impressions, is “meaning perception.” It is more accurate to say causal efficacy is the dim and ambiguous perception of living intensities reverberating from the past, while presentational immediacy is clear and distinct perception of static surfaces arrayed in the present.