Phillips’s solution: Commitment 2

For the sake of argument, let’s assume that Phillips is right about the temporal field. If a change is discriminable within the duration of the temporal field, we directly experience the object’s movement. This tells us about the content of the temporal field as a whole. But we are still don’t know how this can be possible given the fact that we have limited powers of perception. We don’t know what to say about the content over sub-intervals of the temporal field. This is where the idea of determinable content comes in – Phillips’s second commitment. To get an idea of what determinable content is, Phillips discusses an

analogous case (owed to Tye (2002)). If you look at a postage stamp with clear vision you will be able to make out the serrated edges; the content of your experience will be relatively determinate. But if your vision goes sufficiently out of focus, you will no longer see the serrations. Your experience will not represent the stamp’s determinate shape. Nevertheless, the stamp will appear ‘squarish’.

‘Squarishness’ is a determinable property: the edges of a squarish object could be straight, or fuzzy, or serrated, and so on, but ‘squarish’ remains silent as to these finer-grained details. Thus, we can say that the content of our experience of the out-of-focus stamp is in this sense determinable, but not determinate. It represents the stamp’s determinable squarish shape, but does not represent the stamp’s more determinate, serrated form.

Phillips claims that the same can be said of the content of the temporal field. We experience the clock hand’s motion over the 300ms duration. But, due to our perceptual limitations, we are unable to determine any finer-grained details of the motion. There might be a change in velocity, for example, but such details are not represented in experience. Thus, the content of the temporal field is determinable, but not determinate:

It is only over the whole period [of the temporal field] δτ that one has an experience of the hand sweeping out the angle δθ. Moreover, it is not true that over any proper sub-period of δτ that one experiences, or is experiencing, the hand sweeping out some subinterval of δθ: such tiny changes are beyond our powers of discrimination […] The most basic characterization of our experience during a sub-period of δτ is that we are experiencing the second hand sweeping out an angle δθ. We do not experience this sweeping motion in any more determinate way [as] there is no more determinate truth about our experience at such timescales. (Phillips 2011a: 822-23)

It is true that what we are experiencing at an instant (or sub-interval) of the temporal field is motion. But what we are experiencing at an instant is not the hand’s motion at that instant (or sub-interval). Instead, what we are experiencing at that instant is the hand’s movement over a longer period; we simply experience the hand’s motion ‘continuing to unfold’ (Phillips 2011a: 821).

This shows us the way out of the paradox. It follows from Fara2 – that some changes are too small to be perceived – that it is impossible to perceive continuous motion. But it is important to distinguish between continuous and constant motion, at least as Phillips uses the terms. To perceive continuous motion it is necessary for the experiential content to be

determinate ‘all the way down’; we would have to perceive all the fine-grained details of the motion. To perceive constant motion it is sufficient that one experiences motion without any periods during which the object appears stationary. By Commitment 2, the fact that we cannot perceive continuous motion does not entail that we cannot perceive constant motion. Provided the content of the experience is purely determinable over short intervals, we will perceive the motion without all the fine-grained details. Hence, we can experience constant motion without perceiving continuous motion. Fara2 does not preclude Fara1.

It is impossible, Phillips thinks, to make sense of this if we take instantaneous experiential atoms as the most fundamental units of experience. Because the content of experience is purely determinable over short periods, what we experience at an instant is the hand ‘continuing on its motion through the larger interval’ (Phillips 2011a: 822). What this shows is that the content of experience is attributable at an instant only through reference to the content of experience over a longer period. Or, to put it another way, there is no truth about the content of experience at an instant that is not derived from what is true about the content over longer periods. In order to say anything about the content of experience at an instant, we have to first look to the extended experience during which that instant occurs. In short, we can only make sense of experience at an instant if we understand that instant as belonging to an extended experience. Thus, if content is purely determinable at short timescales, we have to accept that it is not instantaneous experiences but extended experiences that are fundamental. As this is the only way out of Fara’s paradox, we must reject the atomistic conception of experience.