Spinoza on Time, Duration and the Mathematization of Nature

Geoffrey Gorham

Macalaster College

When McTaggart (1908) put Spinoza on his short-list of philosophers who considered time unreal, he fell in line with a reading of Spinoza’s philosophy of time advanced by contemporaneous British Idealists and by Hegel. In Faith and Knowledge, for example, Hegel comments that ‘every line of Spinoza’s system makes the proposition that time and succession are mere appearances so utterly trivial that not the slightest trace of novelty and paradox is to be seen in it’. This reading of Spinoza is also common among McTaggart’s contemporaries within the school of British Idealism. Thus, Joachim characterizes ‘limited temporal duration as our mutilation of eternal actuality’. Notwithstanding the strong measure of opportunism in Hegel’s ‘Eleatic’ reconstruction of Spinoza’s metaphysics, there is no shortage of texts, early and late, that prima facie support the ideality of Spinozistic time. In the ‘Metaphysical Thoughts’ (1663) Spinoza emphasizes that ‘time is not an affection of things but a mere mode of thinking’. A private letter from the same year underscores and broadens this doctrine: ‘measure, time and number are nothing but modes of thinking, or rather of the imagination’. (Letter 12) And the imaginary origin of time is confirmed in the Ethics: ‘no one doubts that we imagine time, from the fact that we imagine some bodies to move more slowly than others, or more quickly, or with the same speed’. (EIIP44schol) The idealists understood that there is much at stake concerning the ontological status of Spinozistic time. If time is essential to motion -- as Spinoza's physical writings make clear -- then temporal idealism entails that nearly everything, apart from God conceived sub specie aeternitatis, is imaginary. In the first part of the paper, I argue that although time is indeed ‘imaginary’ -- in a sense ‘no one doubts’ as Spinoza says -- there is no good reason to infer that finite bodies, the infinite modes, and conatus are imaginary in the same sense. To avoid this conflation, we need to follow Spinoza (who follows Descartes) in carefully distinguishing between tempus and duratio. Duration is not only real; it has all the structure needed to ground Spinozistic motion, bodies and conatus. In particular, it is inherently successive. This secures the mundane reality of modes while highlighting the unique and timeless being of God. In the second part of the paper, I examine Spinoza's reasons for relegating time to the imagination. While these reasons are shared by other prominent philosophers known to Spinoza, notably Descartes and Hobbes, in the case of Spinoza they betray a deep antagonism to certain 'mathematization' projects of seventeenth century natural philosophy, in spite of Spinoza's own affection for the more geometrico. Drawing on the work of Gueroult, Schmaltz, Melamed, and the contributors to this symposium, I consider the scientific and epistemological implications of Spinoza's opposition to the mathematization of time, space and motion.