Feeling Time. Amit S. Yahav
relies on Newton’s distinction between absolute time—a durable medium that flows uniformly and equably—and relative time—our approximate measures of this medium. But he uses a different set of terms. Locke uses the word “duration” to mean real, objective temporality, which flows uniformly, equably, and constantly. He uses the phrases “sense of duration” or “idea of duration” to mean our primary notion of what duration is—our personal experience of temporal flow as it gauges real external duration. Locke uses “time” to mean a common measure of duration—an abstraction that relies on principles of periodicity. And, finally, he uses “time in general” to mean our approximations of objective duration which we can deduce from the idea of periodicity. But most important, Locke’s interest in how we come to know the world through our senses prompts him to focus on personal experiences both individual and collective—what he calls “sense of duration” and “time”—rather than on “duration” as such and “time in general.” In this sense, “Locke’s epistemology of time is the mirror image of time in Newton’s natural philosophy,” as Philip Turetzky puts it, investigating time as a dimension of subjective experience more than as an objective medium.3
Locke’s focus on subjectivity is best illustrated at the outset of chapter xiv in Book II of the Essay, where he launches the discussion with his version of the cogito: I think therefore I endure. “For whilst we are thinking,” he writes, “or whilst we receive successively several Ideas in our Minds, we know that we do exist; and so we call the Existence, or the Continuation of the Existence of our selves, or any thing else, Commensurate to the succession of any Ideas in our Minds, the Duration of our selves” (182).4 Locke continues to argue that “we have no perception of Duration, but by considering the train of Ideas, that take their turns in our Understandings. When that succession of Ideas ceases, our perception of Duration ceases with it” (182). He thus disengages any direct relation between time and motion and insists, instead, on the routing of our sense of duration through transformations that we register cognitively. Though time is an absolute external substance, Locke contends, our experience of it relies on the mediation of our psychological capacities, rather than on direct access to external motion.
By equating duration with a perception of thinking and with personal endurance, Locke positions his inquiry squarely in the realm of human time and emphasizes individual consciousness.5 And yet by equating personal endurance with the succession of ideas, Locke opens up his inquiry of time to many of the complications that more generally trouble his examination of human psychology. For the “idea” in Locke’s philosophy is a concept both absolutely central and notoriously vexed, as it marks a porous borderline between external realities and internal experience. Arguing against conceptions of human cognition that rely on innateness, Locke insists that all of our ideas rely on our sense perceptions. But he also recognizes that our perceptions are not simply mirror impressions of an external world. Our cognition mediates stimulation such that most of our ideas are very different from the properties of objects. To begin with, Locke distinguishes between primary and secondary qualities of objects and argues that while our ideas of the first resemble objects, our ideas of the second arise from our sensory apparatuses as these reshape and remake the stimulation emanating from objects. As he describes it, “The particular Bulk, Number, Figure, and Motion of the parts of Fire, or Snow, are really in them, whether any ones Senses perceive them or no: and therefore they may be called real Qualities, because they really exist in those Bodies. But Light, Heat, Whiteness, or Coldness, are no more really in them, than Sickness or Pain is in Manna. Take away the Sensation of them; let not the Eyes see Light, or Colours, nor the Ears hear Sounds; let the Palate not Taste, nor the Nose Smell, and all Colours, Tastes, Odors, and Sounds, as they are such particular Ideas, vanish and cease, and are reduced to their Causes, i.e. Bulk, Figure, and Motion of Parts” (137–38). Color, taste, smell, and sound, Locke explains, do not exist without eyes, tongues, noses, and ears to perceive them. Secondly, attention determines which stimulations register in our understanding to produce ideas and which do not: “A sufficient impulse there may be on the Organ; but it not reaching the observation of the Mind, there follows no perception: And though the motion, that uses to produce the Idea of Sound, be made in the Ear, yet no sound is heard. Want of Sensation in this case, is not through any defect in the Organ, or that the Man’s Ears are less affected, than at other times, when he does hear: but that which uses to produce the Idea, though conveyed in by the usual Organ, not being taken notice of in the Understanding, and so imprinting no Idea on the Mind, there follows no Sensation” (144). If we are already absorbed in a thought of one kind, then any amount of stimulation around us that is irrelevant to that thought will go unnoticed. Finally, memory guarantees that we can have ideas of objects in their absence—that we can have ideas even when our senses do not deliver any external stimulation. As Locke explains, “This laying up of our Ideas in the Repository of the Memory, signifies no more but this, that the Mind has a Power, in many cases, to revive Perceptions, which it has once had, with this additional Perception annexed to them” (150). And he concludes: “Memory, in an intellectual Creature, is necessary in the next degree to Perception. It is of so great moment, that where it is wanting, all the rest of our Faculties are in a great measure useless” (153). Memory turns out to be, in Locke’s account, a supplier of ideas no less than external objects, making perceptions of the external world—once it has been perceived—no longer necessary.
Our cognition thus functions as a mediation that variously shapes and makes ideas and, even more important for my purposes here, shapes and makes succession. Attention, for example, crucially determines the speed and content of the succession of our ideas. If our attention is fixed by one idea, this halts succession, which in turn, by Locke’s initial definition, slows down our sense of duration or even brings it to a standstill. While objective duration may flow equably and uniformly, our primary sense of duration cannot be as steady or regular. And if memory supports the generating of ideas, then this suggests that our succession of ideas may not only, or not simply, be moving forward. If our sense of duration is determined by the succession of ideas, then an idea retrieved from memory supports the experience of time passing from one moment to the next by thrusting us back into a moment that has already passed. Thus even as objective time can only flow from past to future, our primary sense of duration cannot be unidirectional. Moreover, Locke’s account of the mediating role of our cognition entails that any enhancement or diminishment of our capacities—an extraordinarily sharp memory or, conversely, memory loss; attention deficit or, conversely, hyperfocus; the use of technological tools such as a microscope or, conversely, sensory disabilities such as blindness—could radically challenge any generalization a philosopher might make about ideas and their succession.6 For Locke’s inquiry of time, such complications raise two questions. First, how might shared measures and collective experiences of duration arise from the indeterminate and widely varying conditions that generate the succession of ideas in individual minds? And second, what kind of a sense of endurance might we have when our attention, senses, or memories are disabled or significantly altered?
The first question is especially pressing, for throughout his discussion Locke emphasizes our need for shared public measures of time. The mind, he argues, naturally searches for “some measure of this common Duration, whereby it might judge of its different lengths, and consider the distinct Order, wherein several things exist, without which a great part of our Knowledge would be confused, and a great part of History be rendered very useless. This Consideration of Duration, as set out by certain Periods, and marked by certain Measures or Epochs, is that, I think, which most properly we call Time” (187). But how do we arrive at such “Measures or Epochs”? How might we agree on such standards if our primary sense of duration varies contingently? Just as Locke does not explain how we construct and arrive at consensus about language or money, he also does not offer detailed conjectures on how we construct and arrive at consensus about temporal measures. But he does suggest that there are, after all, ways for us to asses durations we do not experience, and this makes possible agreements about conventional measurement. If we need not consult our widely varying experience in our assessments of time, then consensus about extensities becomes much more readily available.
There are many occasions in which we do not experience