There has long been a fruitful relationship between the metaphysics of time and the physical sciences, with physics being particularly prominent in this regard. What does the second law of thermodynamics have to tell us about temporal asymmetry and the arrow of time? Do Einstein’s relativity theories render dynamic conceptions of time which require an objective and universe-wide simultaneity relationship untenable? Do some approaches to a quantum theory of gravity threaten the very existence of time, as some have claimed? These are all familiar issues, at least to those interested in the implications of physics for temporal metaphysics, and all have been much debated. Interesting and important though they are, I am not going to be concerned with them here. I want instead to focus on the relationship between the metaphysics of time and the experiential aspects of time—the manner in which the temporal is manifest in the most basic forms of our consciousness. This has, of course, always been a major topic for those working in the phenomenological tradition, but analytic philosophers have (until recently) paid it comparatively little attention. This is to be regretted: the topic of “time consciousness” is an interesting one in its own right, and—as I hope to show in what follows—there is the potential for a fruitful relationship between the phenomenology and the metaphysics of time.
1. Some Recent Trends in Time and Mind
Irrespective of whether time (really) passes, philosophy changes, often quite rapidly, and both the philosophy of time and the philosophy of mind have altered a good deal over the past couple of decades. Perhaps the most significant change in the philosophy of time has been an upsurge of interest in “ontologically serious” dynamic conceptions of time. While discussion of the linguistically-oriented question of the relationship between A- and B-predicates has by no means ceased, it no longer dominates debates in the way it once did, and is now accompanied by investigations into the competing merits of very different conceptions of the large-scale composition of reality: The Block Universe, Presentism, the Growing Block, the Moving Spotlight—these are all very different accounts of reality (see Figure 1), and all are now being taken seriously by (at least some) philosophers of time.1
The Block Universe
The Moving Spotlight
The Growing Block
Figure 1 The Block Universe and its Competitors: three ontologically serious models of temporal passage. In a Block (or “Eternalist”) universe all objects and events are equally real, and there is no moving or privileged present. If Presentism is true, there is nothingexcept a momentary present. In a Growing Blockuniverse, the sum total of reality increases slice-by-momentary-slice, and the present is the most recent slice to have been created; the future is entirely non-existent. In Moving Spotlight universe there is a privileged (momentary) present, which is steadily advancing in the manner of a spotlight across a darkened stage; the only events which are fully real are those which currently fall under the spotlight of the present; past and future events exist in a lesser way, and do not possess the same range of intrinsic properties as present events.
The main change in the philosophy of mind has, if anything, been even easier to discern: the study of phenomenal consciousness is now respectable to a degree that would have been difficult to predict as late as the 1980’s. Philosophers of mind have always taken an interest in consciousness, but for much of the 20th century it was generally assumed that it would be successfully reduced or eliminated, and so conscious states (or experiences) needn’t be taken to be ingredients of reality in their own right. Over the years a variety of reductive programmes found favour—behaviourism, functionalism, type- and token-identity theory, and more recently a reductive form of “representationalism”—but although some of these still have advocates, it has become widely accepted that all are confronted by difficulties that are serious, and quite possibly insurmountable. As a result, many philosophers of mind—along with those working in related areas of the empirical sciences—have increasingly been prepared to “take consciousness seriously”, i.e., to start from the premise that experience is a fully real and irreducible part of our world.2 Adopting this stance is in some respects liberating—the hopeless-seeming reductionist programmes can be set to one side—but it also means that new (and often, not-so-new) problems can no longer be ignored. If consciousness is real and irreducible, just what is its relationship to the rest of the universe? How do our brains manage to generate experience? What are the basic structures in consciousness? What sorts of contents do our experiences possess?
The heightened interest in consciousness-related issues has led, inevitably, to a renewed interest in the temporal characteristics of experience. Precisely how do temporal phenomena such as change and persistence manifest themselves in our experience? How is it even possible for change to feature in our experience if, as is usually assumed, our experience is confined to the present. Isn’t the present momentary, and so incapable of containing change? Philosophers drawn to these questions have found themselves forced to return and take a closer look at the controversial and long-neglected notion, at least in analytic circles, of the specious present, the brief temporal “window”, perhaps no more than a second long—in apparent temporal depth—through which change and succession are directly apprehended. Although something like a specious present seems needed to make sense of our experience, some have doubted whether a coherent account of it can be provided. But recent investigations suggest this is overly pessimistic. The two main competing accounts of the specious present currently on offer—we will be taking a look at them later on—may both have their unresolved problems, but neither is incoherent, at least not in any obvious way.
In what follows I will be taking a closer look at some of these unresolved problems—since it seems likely that a fair proportion of future research into temporal experience will be concerned with them. But I will also devote some space to arguing for the relevance of the study of temporal experience to the broader metaphysical debates. Of particular relevance here are issues pertaining to the vexed topic of temporal passage. Although both common sense and one important strand of philosophical opinion agree that the main point of difference between time and space is that the former undergoes passage whereas the latter does not, there is very little agreement as to what passage actually involve: the competing conceptions outlined above all have contemporary defenders, and of course there are many others—the Block theorists (or Eternalists)—who hold that time does not in fact pass. Irrespective of where the truth lies on this key metaphysical issue, on one thing there is universal agreement: time certainly seems to pass. For this reason we will only have an adequate understanding of temporal passage, in all its aspects, when we also have something approaching an adequate understanding of what the appearance of passage involves. Since “appearances” are largely a matter of how things register in experience, the study of time consciousness has a key role to play here, and in this inquiry metaphysics must take a back seat behind phenomenology, and the relevant empirical input will come not from physics (probably), but from psychology, psychophysics and neuroscience.
Investigations into temporal experience will not only help us understand the temporal appearances, they can also place some significant constraints on viable metaphysical models of passage, or so I will be arguing. And not only this: if we are prepared to take experience (sufficiently) seriously, the dynamic character of our consciousness is itself enough to cast serious doubt that our universe could be (entirely) passage-free, in the way that some claim. But let us not get ahead of ourselves. An ancient Greek paradox constitutes a useful way into these difficult issues.