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The debate about the nature of time and its passage is a long and venerable one. The issues addressed by pre-Socratic philosophers such as Heraclitus and Parmenides about whether time 'flows' or not prefigure present day philosophical arguments. In his talk to the Blackheath Philosophy Forum Huw Price chose as his starting point the views of cosmologist Sir Arthur Eddington - a prominent figure in the first half of the 20th century, but little known today. What made Eddington's view of time interesting is that he was prepared to part company with most physicists - who conceive time as it is revealed in the laws of physics - and give credence to our subjective perceptions about time, particularly our perception that time passes (or 'goes on' in his terms).[2]

The 'passage' view accords with our commonsense intuitions: that there is a past, present and future - each with a different ontological status. The present moves forward into the future resulting in an ever enlarging past. In contrast, the predominant view among physicists - in Eddington's time and now - is that past, present and future are all equally real and that what we call the present is just a particular location in  four-dimensional spacetime (with time added to the three spatial dimensions). This is termed the block universe view.[4]

What might any of this mean for how we subjectively view time? Einstein, committed to the block universe view, drew comfort from it. In a letter to the family of his close friend Michele Besso, who had just died, he writes:

"For we convinced physicists, the distinction between past, present and future is only an illusion, albeit a persistent one"

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Here Einstein seems to imply that if we accept the block universe view we don't need to be too concerned about the future. I don't know about you, but I will continue to be more anxious about a dental appointment scheduled for tomorrow than one that happened yesterday. Can philosophy and /or physics shed any light on why we think that way?

The aim of this project is to produce a visual map of  the debate about time as an aid to understanding. This is obviously a huge topic with an extensive literature. How might visual mapping make a distinctive contribution? An important feature of the time debate is its cross-disciplinary nature. There are debates about the physics of time; and there are debates about time and conscious experience. Broadly speaking, the goal of this map is to build a visual graph that depicts these two aspects - the physics of time and the phenomenology of time (how time presents directly to our conscious minds) and - crucially - how these two areas are related.

Building a map like this requires some up-front decisions about how it is to be structured. The framing of the debate at the top level - and what this framing implies for the map's structure - is taken up in the node appended to this one in the graph.

Several recent books on the physics and philosophy of time, as well as the book in which Eddington sets out his views on time, are cited below. I have also included a recent article by Huw Price which expands on the content of his talk to the Blackheath Philosophy Forum. Many other sources are cited in the individual nodes that make up the map.