ABSTRACT
The development of modern natural science, we are told in influential accounts like those of Alexander Koyré (Koyré 1957) and Thomas Kuhn (Kuhn 1957, 1962), was a revolutionary rather than a cumulative affair. Very crudely, the geocentric cosmology that the medievals had inherited from ancient Greece was not simply a set of beliefs about which cosmic bodies moved and which were at rest. Rather, it was a complexly organised structure-a “paradigm” in Kuhn’s account-incorporating physical, epistemological and metaphysical aspects. Furthermore, this structure had become invested with rich theological significance, as dramatically exemplified by Galileo’s trial in 1633. Among the features of Aristotelian thought that had to be overthrown in order for the new cosmology to emerge was Aristotle’s account of the nature of space, and it would be in the context of arguments over the new conception of space that Continental idealism would be born. For Aristotle, the most basic notion was not that of “space” but
“place”—topos (Morison 2002). Place was a fundamental concept in the explanation of movement because the elements that made up the terrestrial realm-earth, water, air and fire-were all accorded natural “places” to which they would move if unimpeded. Pick up a sod of earth, release it, and, of course, it will move downwards. Light a fire, and it will be observed that its flames move upwards. The explanations for phenomena such as these appeal to the natural places of elements. Earth has its natural place at the centre of the cosmos, fire has its natural place away from the earth in a layer or shell surrounding it, the layer containing the orbit of the sun, while water and air naturally layer themselves between these two places. Furthermore, in the Aristotelian cosmos there was a differentiation between the sublunar and superlunar realms, with different forms of explanation
applying to each. The sublunar, effectively terrestrial, realm was the realm of generation and decay, while the superlunar or celestial realm was one of constancy and perfection. In the former, motion was between fixed places and, effectively, linear; in the latter, the movement of more perfect bodies, such as that of the stars, was circular, as that is the only form of motion that can go on eternally in finite space. As the derivative term, space was just the totality of differentiated places. Within the scientific cosmology that unfolded between Copernicus and
Newton and that came to replace the ancient geocentric view, there were no differentiated “places” in Aristotle’s sense: space, as finally established by Newton, was “isotropic”. That is, “space”, rather than place, was conceived of as singular, infinite and uniform, and so with no inherent directions. Without fixed given places, there could be no “up” or “down”, as there was in the geocentric cosmos; there could only be the non-subjectively oriented property of tri-dimensionality. Aristotle had been well aware that the notions “up” and “down” had a perspectival character in as much as the direction that was “up” for an observer located on one part of the earth would be “down” for another located on the opposite side of the earth. Nevertheless, this did not imply that they were simply relative to the observer (Phys: 205b34). “Up” was the direction of the natural movement of fire: effectively the direction of lines radiating from the centre of the cosmos to its periphery. “Down” was the opposite direction. And the centre and the periphery of the cosmos were real, objective places. Aristotle’s was not the only view of the nature of space that had been
developed in the ancient world, and he had worked out his conception of space as a finite totality of places, against rival views such as Plato’s, as found in the Timaeus, or those of the atomists. Moreover, after Aristotle, quite different conceptions of space could be found among the Stoics. Importantly, the earlier Platonist view also underwent recurrent revivals and modifications which were meant to allow it to answer various of Aristotle’s criticisms. Such Neoplatonist views in particular would contribute substantively to the conception of space central to the establishment of modern science in the sixteenth and seventeenth centuries. In the sixth century, Philiponus had argued in a very un-Aristotelian and seemingly “modern” way that space was “a certain interval, measurable in three dimensions, incorporeal in its very nature and different from the body contained in it”.1 Later, in the fifteenth century, the fundamentally egocentric nature of the Aristotelian conception was exposed and criticised by Nicholas of Cusa, who conceived of space as an “infinite sphere” whose centre is everywhere and circumference nowhere,2 suggesting that the very idea of a “centre” of the universe was a relativistic or perspectival one. The “centre” was just where the observer was located, and so Cusa claimed that regardless of where an observer were located throughout the universe, it would appear to that observer that they were at the “centre”. With this
conception, Cusa is commonly regarded as looking forward to and, in a way, anticipating, the heliocentric cosmology later to be established by Copernicus (Koyré 1957: 6-24), but Cusa’s thought seems to work on the deeper level of the conceptualisation of the space of the universe itself, and to anticipate later questions concerning the relation of “relative” to “absolute” space. Copernicus reversed the earth-centred view of the cosmos by making the earth revolve around the sun, but this meant that the universe remained finite and still had a centre-the sun. But Giordano Bruno, inspired in part by Cusa, radicalised Copernicus’ move by infinitising the universe and depriving it of both a boundary and a centre, making available the modern infinite and homogeneous conception of space.3
