This essay’s argument centers on two points. The first concerns the suitability of the term “play” to succinctly describe our actual world, which A. N. Whitehead called the world where conflict takes place between “the spirit of change,” which creatively advances toward novelty, and “the spirit of conservation” (Whitehead, 1967/1925, p. 201) —a world where the becoming and perishing of actual entities take place. The second point is that Whitehead’s method of speculative philosophy that includes an exhaustive discussion about this world of play is itself adequately described by the term “play.” Whitehead called the method of his philosophical exploration “speculative philosophy,” describing it as an attempt beginning with “immediate experience” to construct an “adequate and coherent logical system of general ideas” via “imaginative generalization” (Whitehead, 1978/1929, pp. 3-7). What becomes crucial in this search for generality is a “leap of imagination” that entails a departure from the restrictions and particularities of our immediate experience. Whitehead’s comparison of this leap of imagination—a methodology of speculative philosophy—to the flight of an airplane (Whitehead, 1978/1929, p. 5) is well known. We will use another of his metaphorical expressions, “play of free imagination” (ibid.), to refer to this free flight of imagination in this essay. Whitehead suggests that the element of play, as an unrestricted flight of imagination, plays a crucial role in speculative philosophy, as much as does rigorous logic. As such, the concept of play has double meanings in Whitehead’s speculative philosophy, namely because the world that speculative philosophy explores can be understood as a world of play, and the method of speculative philosophy’s exploration involves a play of imagination. This essay will attempt to construct a dialogue between Whitehead’s philosophy of the organism and the philosophies of play, particularly those by F. von Schiller, F. Nietzsche, J. Huizinga, R. Caillois, W. Benjamin, and E. Fink, in order to thoroughly discuss the double meanings of play within speculative philosophy.