How did Alfred North Whitehead explain the philosophy of organism in Process and Reality?

In his seminal work Process and Reality (1929), Alfred North Whitehead articulated his metaphysics, which he termed the "philosophy of organism".1

This system posits that the universe consists entirely of "becomings"—dynamic processes rather than static matter. Whitehead argued that every entity is a process of appropriating and integrating an infinity of items provided by the antecedent universe and by God, who serves as the abiding source of novel possibilities.1

Central to this philosophy is the rejection of "scientific materialism," which Whitehead criticized for mistaking abstract mathematical physics for the concrete reality of nature. Instead, he proposed that the ultimate entities of nature are not inert, but are enduring structures of activity. Each entity reflects its organic relations with the larger structures of nature into which it enters. By emphasizing change, novelty, and the temporal aspects of experience, Whitehead’s philosophy of organism stands as a foundational contribution to process philosophy, challenging traditional Western philosophical reliance on permanence and uniformity.123