Monthly Archives: June 2012

Metaphysics of Time

Previous post: Introduction.

Roughly, one might say that the metaphysics of time concerns whether or not various attributes or features that define time, and so time itself, are possible and/or actual. This breaks down into (i) what is fundamental to time and (ii) whatever this is, whether or not it is possible or actual. The debates about these subjects have led to philosophers developing and/or taking on various metaphysical positions on time. The most notable are A-theory, B-theory, presentism and eternalism. For reasons I hope to make clear as we go along, there are others as well which are less relevant to my project here: the growing block theory, substantivalism vs. relationalism, continuity vs. discrete time, and the debates about temporary intrinsics, composition over time and persistence.

Temporal Passage

Some philosophers (A-theorists) argue that what is variously called temporal passage, the passage of time, the flow of time (or what I sometimes call A-change, e.g., Power 2009) is necessary for time. If you deny the reality of such passage, as some philosophers (B-theorists) do, then, claims the A-theorist, you deny the reality of time. Or, at least, you deny the dynamic aspect of time, of which passage is at least a necessary condition.

The point here is not that you oughtn’t deny the reality of this passage. It is just that doing so denies the reality of time. Our concept of what it is for there to be time, or for time to be real, is that there is this passage. A-theorist argue for this, but also that time is not unreal (and thus there is temporal passage). B-theorists disagree; they deny temporal passage, but not time.

Unreal Time

However, quite eminent philosophers insisted this passage is necessary for time, but deny that it and time are real.

  • One is the formulator of this terminology, John McTaggart Ellis McTaggart. Childhood atheist, Hegelian idealist, believer that ‘man is immortal’, eater of liver for breakfast — in the early 20th Century, McTaggart wrote a(n in)famous paper called ‘the Unreality of Time’. Unsurprisingly given its title, this paper presents an argument that time is unreal (McTaggart 1908).
  • Another is Kurt Godel. He thought the consequences of relativistic physics lead to the the past, present and future being, in reality, indistinguishable (Yourgrau 2005).
  •  There is also some cause to think that Einstein and Minkowski thought something similar: in debate with Bergson, Einstein states that Bergson’s concerns mean that relativity denies the time of the philosophers (meaning, so far as I can tell, the absolute distinction between past, present and future) (see the appendix of Bergson 1999). And Minkowski states that time and space are destined to be mere shadows of their former selves, reducing only to aspects of a four-dimensional manifold, spacetime.

Still, others are not so casual about denying the reality of time, and there has been some debate about what it is for time to be real. These, then, are very brief statements of the main metaphysical positions.

1. Reality in time: Presentism and Eternalism

The debate between presentists and eternalists concerns the reality of things — events, particulars, states, etc. — in any time other than a present time.

  • Presentism holds that only the present exists or is real. The past and future do not exist or are not real.

This means that anything in particular, cats, dogs, a sandwich, the big bang, feelings of irritation, my pot-belly or that great haircut I had in the late nineties: if these are only past or future (e.g., my haircut, the big bang), then they are not real; if these are present (e.g., sigh….my pot-belly, that cat staring at me, half of this sandwich by my laptop), then they are real.

  • Eternalism holds that, whatever time we call past, present or future, anything at any time exists or is real.

This means that anything in particular, cats, dogs, a sandwich, the big bang, feelings of irritation, my pot-belly or that great haircut I had in the late nineties.

Even if these are only past or future (or however else we might want to put it, see below), it is still the case that they are real. Of course, if these are present (e.g., sigh….my pot-belly, that cat staring at me, half of this sandwich by my laptop), then they are real, too.

2. Reality of temporal properties, relations and passage: A-theory and B-theory

One distinction used in the metaphysics of time is between two ways that we think of events as being ordered in time. The two ways events are ordered are described by McTaggart as two series in which think of events in time: the A-series and the B-series.

  • The A-series is the series of events running from the far past, through the recent past, through the present, through the near future, to the far future. According to different moments in time, events have different positions in the A-series. Positions in this series are sometimes also called tenses or A-properties.
  • The B-series is the series of events ordered by B-relations: precedence, simultaneity, ‘earlier than’, ‘later than’, ‘at the same time as’. No matter the moment in time, events stand in the same B-relations to each other, and thus in the same position in the B-series.
  • A-theory is the theory that there is a fundamental difference between the past, present and future.

There are two claims made by the A-theorist.

1. Tenses/A-properties/positions in the A-series/positions in the past, present and/or future are real: Things that are past are really and irreducibly past; things that are future are really and irreducibly future; things that are present are really and irreducibly present. The present and the past and future (including degrees of the latter two, e.g., ‘two days past’ or ‘three years in the future’) are sometimes called tenses. They are also sometimes referred to as A-properties or positions in the A-seriesthe name McTaggart gives to the series of events that is through the future, present and past. This position is sometimes also called the tense theory.

2. A-theorists/Tense theorists also typically advocate the idea that time needs change in events from one of these tenses to another, i.e., temporal passage (what I call ‘A-change’ above). And, also, being A-theorists, and not McTaggart, they argue that such change is real — and thus time is real.

  • B-theorists do not think that such temporal passage or A-change is real; nor do they think it is necessary for time. Only temporal relations are needed for time.

For a B-theorist, there can be real time without there being real tenses, tensed facts, change in tenses, temporal passage etc, or all the other structure endorsed by A-theorists. Instead, all that are needed and all that there is are temporal relations of precedence, simultaneity and succession: ‘before/after’, ‘at the same time’, and so on. These temporal relations are not tensed relations, and sometimes B-theorists are called detensers or tenseless theorists. Again, one is such a theorist because one holds the relevant temporal structure to be real. But it’s not as clear that B-theorists think that such a structure is necessary for time. It is more that B-theorists think it is sufficient for time and that the A-theorist’s structure — passage, fundamental tense — is not necessary for time.

The presentism and eternalist debate is often identified closely with a debate about the whether or not the A-series or the B-series is more fundamental to one’s concept of time. But there are subtle differences: in the debate about temporal properties and relations, the reality of events at other times might be held by both sides. What is at issue is whether or not the difference between the past, present and future is a real distinction, and also whether or not it is fundamental to our concept of time. The issue not whether or not the past and future are unreal. However, the latter is a question which depends somewhat on an answer to the former. For if there is no real distinction between the past, present and future (as implied by the standard interpretation of relativistic physics), it is hard to see how one can say only what is present is real.

A brief statement on the relevance of these distinctions to the project

A central point of this project is that, in shifting between A- and B- theory (or what we might also call tense and tenseless theory) as well as shifting between presentism and eternalism, one shifts between different views of what is real or exists. In doing this, one shifts between different views of what is illusory. The metaphysical condition is satisfied in different ways, leading to different discrepancies with the same phenomenological condition, i.e., the same appearance. This is what leads to different cases of illusion.

A much-discussed example in the metaphysics of time is that of temporal passage, which is supposed to be a problem for tenseless theory. But as will be seen as these posts progress, this is not the only discrepancy. There are other conflicts between concepts of time and phenomenology. This project makes what I consider to be two important claims:

(a) Not all discrepancies are due to the claimed ‘counter-intutive’ conceptions of time; the intuitive conceptions have the own particular discrepancies.

(b) Such discrepancies do not all concern what we might understand as the appearance or phenomenology of time. Because of the role time plays in the structure and occurrence of other entities, particularly concrete particulars, ones concept of time changes what it is that one can claim to perceive, to be conscious of, or even the structure of experience itself. In making the case for any illusion,  one ought to consider how one’s thinking about time plays a role.

My position in this debate

I have sympathy with B-theory over A-theory, and eternalism over presentism. But I am motivated to my views on time by relativity which means that I am not sure that I am entirely sympathetic with B-theory.

For example, simultaneity between spatially separated things is relative given modern physics and I wonder if we should strictly speaking talk about this simultaneity as a temporal relation. In relativity, simultaneity is like spatial co-location along one dimension but not along others. If I hold my hand up in front of the moon, and ignore the distance between them, I might say that both my hand and moon are in the same place, to be co-located. But is this co-location a real spatial relation, be it relative or otherwise, between my hand and the moon. If it isn’t, I feel simultaneity (again, specifically) between spatially separated things is not a real temporal relation.

Also, less relevant to relativity, I think that, actually, in practice, we move between different conceptions of time in our thinking, without necessarily noticing that we do, and this can lead to confusion about time. I think this is the source of our thinking of one view advocating a ‘static’ view of time.

I do not think we should think, as some B-theorists seem to think, that time is a static block. Whatever we are talking about in talking about temporal relations such as ‘simultaneity’ and ‘succession’, they cannot be said to either persist or desist, or remain fixed or changing, or anything else with temporality built into its expression (recently, from a conference in Durham, I’ve become aware that Oaklander is expressing similar thoughts, and I will probably post on that in future).

Other metaphysical issues regarding time:


Three concepts of ‘content’ and one of constitution.

My friend E. is across the hall from me in the Materials Science department. She often comes by to say hi, and then argue about various differences between what philosophers should do and what material scientists should do (I am clear in my opinions about the latter, she in her opinions about the former). E. has some grasp of the terminology used in philosophy, and so can understand a lot of what I say, when I am overwhelmed by frustration and rage — in ‘High Dudgeon’, as she puts it — over some argument about properties, instantiation and possible worlds. E. is also our building’s Fire, Health and Safety Officer; she sometimes does a tour to make sure everything is good (and frequently to get into a ‘High Dudgeon’ about people propping open fire doors with extinguishers etc.).

Last week, I was struggling with a paper about the structure of perception. It was getting worse and worse, as I seemed to have found an argument for the position that, necessarily, perception could have no structure. Finally, I ROARED with mighty rage, I SHOVED my desk back, I PRINTED my paper, and then I grabbed it and TORE it to shreds, before finally flinging it into the wastepaper basket with such force that the bin fell over.

A minute later, as I sat on my desk, head in hands, there was a knock on the door. E. stuck her head in. I gazed up in mute defeat.

She looked at me, then looked at the bin.

“What’s in the bin?”

“What?”  I asked.

“The bin. What’s the bin’s content?”

“Oh –” I took a trembling breath. Hardly able to bear the answer, I spoke just above a whisper. “Its content is an argument for the simplicity of the perceptual act.” I wanted to weep.

Now, E. looked confused. She came in to the room “–No. I mean: what’s in the bin.”

I stared a moment then understood: “Oh” I gestured irritably. “Just paper. And an empty packet of Jaffa Cakes.”

E. sighed noisily and stamped over to the bin. She picked it up, ignoring everything that fell out of it, and turned it over to look at its bottom. “Right –” she read out. “Material content: 40% tin; 40% aluminium; 20% plastic.” She frowned, and left the room.

After a moment, I shouted after her:

“Hey, that’s not content!”


One talks of

1. Content = what something is about, refers to, etc., e.g., the content of the sentence: ‘The dog is in the kitchen’ is what that sentence refers to. Call this content_1.

2. Content = what something contains, but of which it neither refers to nor is constituted by. Something encompasses, engulfs, is a container for it. The container is separate to it. For spatial objects, the container is spatially separated from it. For any other cases, the distinction is less clear (which is why spatial examples are easy, and others not). E.g., paper is the content of the bin in which it’s been thrown. Call this content_2. (Siegel 2010 calls this ‘bucket content’. See below).

3. Content = what something is composed of, constituted, but of which reference need have no relevance. This content is part but not all of the thing to which it belongs. One might talk of a container, of something engulfing or encompassing the content, but the content in this sense is part of it as well. One would talk about my body containing blood, or DNA in this way.  The content of a metal ingot is mainly iron. Chocolate contains sugar and cocoa (just look at the ingredients on the packet). Call this content_3.

  • Content_1 is likely to be what most philosophers mean by ‘content’ when talking about mental content, perceptual content, and such-like. As Siegel 2010 puts it:

“When one speaks of the contents of a bucket, one is talking about what is spatially inside the bucket. An analogous use of “the contents of perception” would pick out what is ‘in the mind’ when one has a perceptual experience. In contrast, when one speaks of the contents of a newspaper, one is talking about what information the newspaper stories convey. Most contemporary uses of “the contents of perception” take such contents to be analogous to the contents of a newspaper story, rather than the contents of a bucket. This notion of content can straightforwardly accommodate the idea that there is such a thing as the ‘testimony of the senses’.”

I take it that it comes from the philosophy of language, from which a lot of contemporary philosophy of mind has developed (just consider the line from Wittgenstein, through Anscombe, through to Lycan, to the representational model of consciousness and qualia; see Lycan; for critical views, see White and Robinson).
So, Content_1 is representational or intentional content; it encompasses talk of narrow and wide content. It includes for some philosophers perceptual content and phenomenological content (which of course is relevant to what I say here), even if such philosophers deny that there is any such content, e.g., David Bain tells me that Bill Brewer, in his arguments against a conceptualisation of perception, argues that there is no perceptual content. I don’t think anyone here means that there is no content in the senses of a bin or alloy.
  • However, when combined with issues in metaphysics and ontology — with philosophy which cares about what things exist in the world, and how to explain them — there is some scope for ambiguity here. One might think that what is meant by ‘content’ is Content_2: what is in a mind in the sense that the mind is quite literally a container of some sort; thinking of the mind this way has the metaphysically interesting commitment that minds can (again, quite literally) encompass, hold or engulf something that is not mental. Or: one might think that what is meant by ‘content’ is Content_3: what is ‘in’ a mind is a constituent of it.
  • Maybe not much scope for ambiguity. But it matters, because of the different commitments and the different assumptions one can make about the relationship between the mind and content, and the ontological implications of asserting the relationship. There are very different implications for each.
  • Given ‘content_1’, one can talk about the mental event having content even if it is not the case thatthe content exists or is real. The content is inexistent, meaning it need not be real but can be real (which is why it is inexistent, not nonexistent). I can think about the argument for the necessary structurelessness of perception without there being any such argument. Better:   I can think about being chased by an angry unicorn through a Liqorice Forest without being chased by anything, or there being unicorns or liqorice (p.s., I hate liqorice).
  • Given ‘content_2’, one can talk about the mental event having content only if it is the case that the content is real. But one can also strip away all content, and still have a mental event. So the mental event does not depend on there being Content_2 for it to occur itself. As there’s still the bin, even if it’s empty, so, if a mental event has no Content_2, there is still the mental event.
  • Given ‘content_3’, one can talk about the mental event having content only if it is the case that the content is real. And if one strips away all content, we do not have that mental event. This is because Content_3 constitutes or is an element of the mental event itself. As a house cannot exist without some kind of structures like walls, roofs, foundations, etc., or a ship cannot exist without planks, sails, or some kind of constituting material, so minds cannot exist without Content_3.

The point here is not that professional philosophers ever talk any of these ways about the content of mental events. It is that people do so in everyday talk. And there are interestingly different ontological implications from each concept of content (as other philosophers might agree, e.g., Siegel writes that ‘The claim that experiences have contents in this sense[Content_1, in my terms here] is substantive’).


That perception and experiences have representational content might be substantive, and this is likely to come out as the discussion on time and illusion progresses. But I am particularly concerned here with (what I call here) ‘Content_3’. This is because I am interested in the structure of perceptions: how perceptions occur, how they are made, what elements are necessary in order that they can occur such that, if you removed those elements, you could not get a perception. I am interested in the temporal and spatial properties of perceptions and their causes. I am interested in the range of causes of perception.

But more importantly, I am interested in what Rowlands 2010 calls the constituents and constitution of perception; one might also include the relations that hold between the entities that compose a perception (these are what I have called the real perceptual structure and elements of perception). It is also what is referred to by Content_3. But I will not call it content, in order to avoid confusion with how philosophers of mind talk.

Why talk about the constitution and composition of perception? Unless one supposes that perception has no structure (see despair above) then like anything with structure, it has elements, relations between them, and so on, i.e., it is constituted in some way. Not only that: unlike ‘Content_1’, unlike representational content, which can include unicorns, monkeys with wings, and other inexistent things, such structure, such constitution involves a commitment about what is real, about what exists, about what there is, because it implies a commitment to what makes it possible for perceptions to happen. I consider this important — more important than questions about ‘Content_1’ which, unless it involves commitment to something regarding the constitution, is of less interest to me.

Many philosophers might reply here that perceptual content, in the sense of Content_1, also implies commitment: perceptual content is what we perceive; what we perceive is real; perceptual content is real. But I have found that, when it comes to debates about time, this is far less obvious in the thinkers around it. They seem to treat the temporal content of perception as intentional content that requires no ontological commitment, no positing of the contents as real, i.e., as a form of Content_1. For example, regarding the perception and general experience of time, Grush 2005 states that a lot of problems regarding it come from confusing the vehicle and content (e.g,, Grush 2005, and I’ve been told Tye has said something similar(but have no references)). I can’t see why there is too much of an issue here if one is committed to the reality of both the vehicle and content of perception. In any case, the point here is: whatever we say about perceptual content, what we say about perceptual composition involves a commitment to what is real.

Getting down here, I realise I need to make One Last Point: when I say perception is constituted, I mean it is not simple, and is composed of entities standing in relation to each other. I do not mean that it is actively constituted or fabricated, that the subject of perception makes it, or that there is any sort of intent guiding a construction of it. I am not going as far as making the claim, however true, that perceptions are constructed as wasps nests, buildings, microscopes or warrens are constructed; I am only claiming that they are constituted as a cloud, a ruin, a puddle of water or a mole hill are constituted.