If the universe is composed of actual occasions, brief events of becoming, then the most important question is: how do they relate to each other? How does each new occasion arise from those that preceded it? Whitehead's answer is among the most original concepts in modern philosophy: prehension.
The analogy that makes prehension vivid: imagine you are sitting in a concert hall as the orchestra plays. As the music unfolds, each new phrase arrives against the background of everything you have just heard. The new phrase is not heard in isolation; it is felt as it arrives into the accumulated resonance of what preceded it. The past notes do not disappear when they cease, they continue to reverberate, shaping how you receive the present. The present moment of musical experience is constituted by its feeling-uptake of everything before it.
This is prehension: the way each actual occasion feels-into-itself the whole of its past, appropriating and transforming that inheritance in the process of its own becoming. Prehension is not like perception, it is not a conscious act by a subject looking at objects. It is the fundamental process by which any event comes to be at all. Every actual occasion prehends every other occasion in its past, selectively, with varying degrees of intensity, taking some influences strongly and others weakly, and synthesizes all of this into its own unified moment of experience.
"The creativity of the world is the throbbing emotion of the past hurling itself into a new transcendent fact."
— Whitehead, quoted in Footnotes2Plato 'Whitehead's Revolutionary Concept of Prehension' (2025)
Prehension is what replaces causation in Whitehead's framework. In classical physics, cause and effect are mechanical: billiard ball A hits billiard ball B and transmits momentum. In Whitehead's framework, the past does not mechanically push the present, it is felt by the present, taken up, absorbed, and creatively synthesized. This is why Whitehead says the universe has an irreducible element of creativity: each occasion does not just receive the past but responds to it with some degree of self-determination, even the most rudimentary physical event has a tiny but real element of novelty, of "how it incorporates its data," that cannot be fully determined by its inputs.
What prevents this from collapsing into pure chaos, occasions just doing whatever they like, is what Whitehead calls the eternal objects: the pure possibilities (something like Platonic forms, but not Platonic) that any occasion might actualize. Each occasion inherits the past through physical prehension and reaches toward possibilities through conceptual prehension. The balance between continuity (inheritance) and novelty (creativity) is what gives the universe both its lawful regularities and its genuine openness.
Whitehead also introduces God into his metaphysics, not as an omnipotent ruler but as a structural feature of the cosmic process. God's primordial nature is the infinite set of possibilities (eternal objects) available for any occasion to actualize, God is the ground of novelty and possibility. God's consequent nature is God's reception and preservation of every actual occasion as it perishes, God is the memory and appreciation of everything that happens. This is not the God of traditional theism; Whitehead explicitly says God is not an exception to the metaphysical principles but their chief exemplification. Process theology, a significant theological tradition developing Whitehead's thought, has made substantial use of this framework.