A Framework for Reconciling “Now” with Eternalism
Spoiler alert: There are turtles all the way down.
From an eternalist perspective, time exists as a dimension (coordinate) of spacetime, and the flow of time is an illusion. If we compare a region of 3-dimensional space and its temporal cross sections to a video and its constituent frames, time becomes the equivalent of frame numbers. Similarly, if we use the metaphor of spacetime as a book, time becomes the page numbers.
And just as video frames and book pages are usually numbered in sequence, it is conceivable that there is an objective arrow of time behind the evolution of events in space. Most likely, this is defined by the entropy gradient as described by the Second Law of Thermodynamics.
So from this perspective, we have time as pointer (frame/page #), and we have an arrow of time. But what of the flow of time and the sense of “now”? Is there any way to begin to characterize these experiences? Well, I believe there is, but it requires that we expand our metaphors in an unconventional manner.
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Media such as books and videos do not exist in a vacuum. Videos are made to be watched, and books are meant to be read. Let’s ignore the exact nature of the reader or the watcher, and refer to them collectively as “the audience”. The audience inhabits a world or “library”, which in some meaningful way has more degrees of freedom than the media. By which I mean that in the library, the media and all of its pages/frames can be viewed simultaneously, as a whole, from what we would call an eternalist perspective.
But the audience is not limited to this vantage point. They can also choose to interact with the media by selecting a starting point (page or frame), narrowing their attention to that slice of the whole, and then shifting their attention through a sequence of such slices in a particular direction. This is what we mean by reading a book, watching a video, or perhaps living a life.
We can visualize this as follows:
The dependent axis indicates the position within the media. For a book, this corresponds to the page number. For a video, this would be the frame number. For the general case, I will call this the “temporal position”. The independent axis indicates the duration for which the audience attends to the media. What exactly this extent is measured against is slippery, as it is analogous to our concept of time, but has nothing to do with spacetime itself. Rather, it is a higher dimensional property of the library in which the audience and media are embedded, the “library clock” if you will.
As the audience attends to the media, the process defines what I’ll call an experience curve. I chose this term because it denotes the experience of reading the book/watching the video/living the life. The slope (derivative) of this curve indicates the framerate i.e., the number of frames per increment of attention, which (finally) gives us a quantity corresponding to “flow of time”. The steeper the experience curve, the higher the framerate and the faster the subjective flow of time.
Further, it is possible to define a “now” with respect to spacetime by identifying library “now” on the attention axis, extending a vertical line upward until it intersects with the experience curve, and then reading off the temporal coordinate (temporal position) from the dependent axis. Doing so would be the equivalent of asking the audience “Where are you in the story?” (A: “I’m up to the part where the hero does x, y, and z.”)
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Comparing spacetime to a book, video or similar media clarifies the notion of an arrow of time, but does not in itself suggest any explanation for the perceived flow of time or the present moment. If we extend such metaphors however to imagine an embedded media and an interaction with an audience, we can inherit both flow and “now” from the physical properties of the higher dimensional “library”. Doing so requires two assumptions that may be untenable depending on your philosophical bent: 1) Consciousness is characterized here not as an epiphenomenon but rather as fundamentally independent of spacetime. 2) Both the flow of time and the sense of “now” stem from the interaction of audience and spacetime within a higher dimensional context. This immediately leads to an infinite regress, as explaining the properties of library time requires an appeal to an even higher dimensional space. In other words, if you find this explanation interesting, you’d better be comfortable with turtles all the way down…
