Moving Spotlight Metaphysics and Other Stuff

Interview by Richard Marshall

'I think metaphysics is what its always been - and its hard to say what that is!  I think its in a pretty good state: weve emerged from the darkness of logical positivism, ordinary language philosophy, and conceptual analysis, and are once again unapologetically trying to say something about reality!'

'The Moving Spotlight view shares with presentism the idea that one moment in time is special, but it denies that the present is all that there is.  According to the Moving Spotlight view, past objects like Julius Caesar, along with their temporal locations, exist, as do future objects like the first Martian colony, and their temporal locations.'

'It might be useful, maybe even mandated, to think about reality in certain terms, but that doesnt mean that reality is in fact that way.  My reasons for being an A-Theorist are resolutely metaphysical ones, not ones to do with thought or language.'

'I think that when we ask whether Caesar exists, existsdoesnt mean either of those things.  It just means . . . exists!  Were asking whether Caesar exists simpliciter.  When you ask God what exists, will Caesar be on that list or not?'

'Grounding is real.  What it is is another issue.'

'Planets and cars arent just errors of thought, they exist, and there are true things to be said about them.  But what makes those things true?'

'I donthink that vagueness is a case where we should see gaps or gluts.  So I dont think the sorites paradox is a reason to abandon classical logic or bivalence.'

Ross P Cameron is interested in all areas of metaphysics.  He has published extensively on traditional metaphysical topics like the nature of time, possibility, existence and truth.  He is also interested in the history of metaphysics, especially the medievals, Leibniz and early analytic philosophy.  He enjoys exploring the connections between metaphysics and other areas of philosophy, especially aesthetics, the philosophy of religion and epistemology. Here he discusses the state of contemporary metaphysics, the metaphysics of time, the Moving Spotlight view of time and its rivals, McTaggart's paradox, the notion of existence simpliciter', how we know we are in the present, grounding, whether we can have a minimal ontology and cars, mereology, truthmaker maximalism, vagueness and whats metaphysical about metaphysical necessity plus a survey of philosophical positions cribbed from one done by David Chalmers some years ago.

3:16:    What made you become a philosopher?

Ross P Cameron:  Like many philosophers, in retrospect I was interested in philosophical questions for as far back as I can remember, but of course I didnt know that it was philosophy I was interested in.  My dad was a math teacher, and when I was a kid we would talk about paradoxes and the philosophy of math, although neither of us would have known to use that description.  I was always interested in really abstract questions like the possibility of an infinite series, time-travel, why there is something rather than nothing, and so on.  Again, like many philosophers, I showed up at University to study math and physics, thinking that was the way to investigate the issues I was interested in. But my mum had gone back to university as an adult and luckily she had taken some political philosophy classes, and we would argue about social contract theory over dinner, and she urged me to take at least one philosophy class. I quickly realized that to pursue the kinds of questions Id always been interested in, I was much better off studying philosophy. And thankfully, I was at University in Scotland and not England, so I had more flexibility to change my course of study - although not nearly as much flexibility as students have in the US. So I suppose the short answer is: I became a philosopher because of my natural interest in those issues, the guidance of my parents, and utter luck.  I am very much in favor of teaching philosophy in school (and under that description) so that future philosophers dont have to rely so much on luck!

3:16:   Youre interested in various metaphysical issues. Before we look at some of them, can you tell us about the state of contemporary metaphysics as you see it. What is metaphysics these days and are there features of the contemporary scene that might surprise someone coming from the pre Lewis/Kripke times?

RPC: I think metaphysics is what its always been - and its hard to say what that is!  I think its in a pretty good state: weve emerged from the darkness of logical positivism, ordinary language philosophy, and conceptual analysis, and are once again unapologetically trying to say something about reality!  I suppose one thing that might surprise someone coming from near pre-Lewis/Kripke times is the variety of phenomena that are taken to be legitimate subjects of metaphysical theorizing. (Although it wouldnt be at all surprising to someone from farther back in the history of philosophy.) People still do the metaphysics of time, possibility, existence, etc., but also the metaphysics of race, gender, disability, social groups, sexuality, etc.  One sociological change is that its become absolutely standard to see these topics in metaphysics textbooks, being taught to undergraduates, being presented at mainstream metaphysics conferences, etc.  I think thats a very good thing.

3:16: One of the philosophical issues youre interested in is giving an account of time. You defend the view that time is a genuine feature of reality, a version of the moving spotlight’ view of time which is labeled the A-Theory. So what makes an A-Theory an A-Theory, and how does your version contrast with other versions of A-Theories?

RPC:A-Theoryis a term of art, and it means slightly different things to different people, so I dont want to legislate a particular meaning.  But what I mean by A-Theory- what I took, somewhat stipulatively, to be the core of those views - is the conjunction of two claims: (1) That there is a unique objectively privileged moment in time - the present; and (2) That which moment in time is  the unique objectively privileged moment changes.

 The most popular A-Theory is Presentism.  The presentist says that only the present moment is real: and, hence, only present events are happening, and the only objects that exist are those that exist in the present.  So the present is objectively privileged by virtue of existing, but as time passes what was present ceases to be, and new things come into being, and so a new time becomes the objectively privileged moment.

 The Moving Spotlight view shares with presentism the idea that one moment in time is special, but it denies that the present is all that there is.  According to the Moving Spotlight view, past objects like Julius Caesar, along with their temporal locations, exist, as do future objects like the first Martian colony, and their temporal locations. Nevertheless, there is something metaphysically special about the present and what is happening now. (Of course, this leaves a lot more to be said, and Moving Spotlighters will differ on the details: the view I accept is different from the view that my fellow Moving Spotlighter Daniel Deasy accepts, and neither of us accept the view that is gestured at by CD Broad, who coined the term.)

The third main contender is the Growing Block view, which accepts the existence of past and present times and beings, but denies the existence of the future, so that as time passes more and more things come into being, but nothing ever passes out of being.

In accepting the existence of past and future things, the Moving Spotlight is an eternalist view.  Most eternalists are B-Theorists (see the next question), which by the A-Theorists lights is a static metaphysics that doesnt allow for genuine change or openness concerning the future.  Presentism is a dynamic metaphysics on which reality is constantly changing, but in eschewing past and future ontology the presentist has a hard time saying what accounts for truths concerning how things were or will be.  As I see it, the Moving Spotlight view can give us the best of both worlds: genuine change, but with a metaphysical underpinning for historical and future truths.  (The Growing Block is my least favorite of all these views. All that it apparently has going for it is that it can offer an account of why the past is fixed and the future is open.  But I argue that appearances are deceiving here, and that presentism and the Moving Spotlight can do just as well on this score, but each with their own advantages over the Growing Block.)

3:16: What are the main non-moving spotlight rival theories that the A-Theory challenges?

RPC: Presentism and the growing block, as mentioned above.  And, of course, the B-Theory.  The B-Theory denies that there is a privileged moment in time. Just as all places in space are metaphysically on a par - theres nothing special about where I am as opposed to where you are, it just happens to be my location - the B-Theorist thinks that all times are metaphysically on a par: theres nothing special about 2019 as opposed to 1066, it just happens to be the time we are at.  Time, for the B-Theorist, really is just another dimension like the spatial dimensions, and change is just variation across that dimension.  According to the B-Theory theres nothing metaphysically different between a striped shirt that varies in color across space and a growing person that varies in height across time.  Thats why some A-Theorists say that on the B-Theory, theres not reallyany change.

The B-Theory is the main rival for all A-Theories.  Disagreements among A-Theorists are fights among friends, but at the end of the day were arguing over the details concerning our shared conception of how time works. The B-Theorist thinks of reality in a fundamentally different way.  (For the record, some of my best friends are B-Theorists . . .)

3:16: You say that A-Theory is not a theory about tensed talk or thought and yet justifying it seems to draw on the usefulness and ineliminability of having such talk and thought as a major part of the justification. But metaphysics is full of examples of things that are useful but not real so some will argue that composite objects arent real but theyre useful. Why is time not like that especially given that McTaggarts paradox seems on the face of it to target time realists like yourself?

RPC: I actually dont think that the usefulness and ineliminability of tensed talk and thought is a major part of the justification for the A-Theory.  Or even a minor part, for that matter!  Those kinds of considerations play no role in my own reasons for being an A-Theorist.  For exactly the reason you suggest: it might be useful, maybe even mandated, to think about reality in certain terms, but that doesnt mean that reality is in fact that way.  My reasons for being an A-Theorist are resolutely metaphysical ones, not ones to do with thought or language.  There are two main reasons.  First, I think you have to be an A-Theorist if you believe that the future is genuinely open, for that requires that there be an objective metaphysical distinction between the past (which is fixed) and the future (which is open), which requires that there is an objective moment in time (the present) that marks the transition from the fixed past from the open future. 

Second, I argue that endurantism entails the A-Theory.  Endurantism is the view that objects like you and I persist through time in such a way that the entirety of us can be found whenever we exist.  That is in contrast to Perdurantism. For the perdurantist, things stretch out through time much like the Blue Ridge Parkway moves through states. The Parkway has some parts entirely located in Virginia and some other parts entirely located in North Carolina, and it itself spans both states by being made up of these distinct spatial parts.  Similarly, the perdurantist thinks that I persist by having some temporal parts entirely located in 1990, some other temporal parts entirely located in 2000, yet others entirely located in 2019, etc., and I myself span my temporal lifespan by being made up of these distinct temporal parts.  So according to perdurantism, you never find the whole of a persisting object, youre only ever encountering a small temporal part of it, whereas the endurantist thinks that all of me is here now: no part left behind!  One of my reasons for being an A-Theorist is that I am also an endurantist, and I think the combination of the B-Theory and endurantism is unstable, because it cannot explain the evident fact that things appear differently at different times.

 Of course, these defenses of the A-Theory are only as good as their starting points, and arent going to convince anyone who isnt already convinced that the future is open or that objects persist by enduring.  But thats philosophy for you: theres always another fight to be had.

 As to McTaggarts paradox, I (unlike some A-Theorists) think theres a puzzle there that needs to be addressed, but I dont think every A-Theory is vulnerable to it.  I argue that what gets you into trouble with McTaggarts paradox is not just the A-Theory but also a commitment to what I call Past Record: the claim that if something wasthe case, then it isthe case in the past.  Clearly, the presentist denies that principle (there is no past, so nothing is the case in the past) and hence, I think, faces no problem.  You might expect non-presentist A-Theories like the Moving Spotlight and Growing Block to entail this principle, and hence be vulnerable to McTaggarts paradox.  But my version of the Moving Spotlight view rejects this principle and hence, I argue, does not face McTaggart-style problems.  So rather than being an argument against A-Theories, I see McTaggart as giving us a constraint that any successful A-Theory must meet. Presentism meets it easily, but non-presentist A-Theories can also meet it, they just have to be more careful.

3:16: Is the A-Theory about the irreducibility of A-properties or the clam that theres a metaphysical difference between space and time?

RBC: Neither, as I see it.  Combined with certain other commitments, the A-Theorist might find themselves drawn to make a claim concerning the irreducibility of A-properties, or concerning the difference between space and time, but I dont think any such claims are part and parcel of the A-Theory itself.  Take e.g. the claim that theres a metaphysical difference between space and time. Its natural for the A-Theorist to accept this claim, but only because almost everyone - A-Theorist and B-Theorist alike - is already committed to certain views concerning what space is like.  But just as the B-Theorist spatializes time, one could temporalizespace, and hold that there is a privileged point in space (probably in Scotland), and a privileged direction in space, etc.  Just as the presentist believes in only one time, you could believe in only one spatial location.  I dont recommend this, but the point is: being an A-Theorist alone wont tell you that theres a difference between space and time, because its just a theory of time, so you need a theory of space as well to work out if theres a difference.

3:16: Does any thesis about how truths correspond to reality follow from an A-Theory?

RPC: No, I think those debates are pretty orthogonal.  I rely on a certain kind of correspondence view of truth in my own arguments for my view, most obviously when I argue for the Moving Spotlight over Presentism on the grounds that we need past and future objects to make true claims concerning what did or will happen.  But while that correspondence view plays a role in my own route to my own version of the A-Theory, I dont think its a consequence of even my own view, let alone the A-Theory in general. 

3:16:  You are committed to having the notion of existence simpliciter'. Can you explain what you mean by this and why you need it?

RPC: Suppose you ask whether Alpha Centauri is to the left of our Sun.  I cant answer that.  Not even God could answer that.  And thats because its a bad question: theres no such thing as being to the left of simpliciter. Theres only being to the left of from a certain perspective.  Once you fill in the perspective, the question makes sense, and God at least can tell you the answer.

Suppose you ask God whether Caesar exists.  I think God can answer that question with a straightforward yesor no.  He doesnt need you to fill in the perspective from which youre asking.  Thats what it means for there to be a notion of existence simpliciter.  God can give you a list of what exists.  He doesnt need to say: well, these things exists from this perspective, and those things exist from that perspective, etc.

Heres why I need it.  Recall the debate I had above with the Presentist.  I think that Caesar exists, and they dont.  Some people argue that this is a pseudo-debate, turning only on what we mean by exists.  Exists’ might mean exists now, in which case the Presentist is clearly correct that Caesar doesnt exist, and the characteristic presentist thesis Everything that exists, exists now’ is trivially true.  Or exists’ might mean exists now, or did exist, or will exist, in which case the eternalist is clearly correct that Caesar exists, and the presentists thesis is obviously (if not trivially) false.  If these are the only two options, there is no good debate to be had between the presentist and the eternalist.

I think that when we ask whether Caesar exists, existsdoesnt mean either of those things.  It just means . . . exists!  Were asking whether Caesar exists simpliciter.  When you ask God what exists, will Caesar be on that list or not? Existence simpliciter needs to be a legitimate notion in order for this question to make sense and the debate between the presentist and eternalist be a genuine one.

I find it very hard to think myself into the headspace of denying the legitimacy of the notion of existence simpliciter.  And note that this move only seems to get made in certain debates.  Consider the debate between a nominalist and a Platonist about abstract objects.  The Platonist says abstract objects exist, the nominalist says they do not.  Suppose I said this was a pseudo-problem because either existshere means exists abstractly’ - and everyone should agree that abstract objects exist abstractly, or it means exists concretely’ - and nobody thinks that abstract objects exist concretely.  The nominalists thesis Everything that exists is concrete, I continue, is either trivial, if exists’ means exists concretely, or false, if exists ’ means exists abstractly.  I dont think this is a tempting thought.  The debate is whether abstract objects exist . . . simpliciter ! Are they on Gods list or not?  The notion of existence simpliciter seems to make perfect sense when were asking most ontological questions, but some people seem to lose their nerve when it comes to temporal ontology.  I recommend a whisky to steady the nerves.


[The interviewer's fave whiskey]

3:16: How do we know according to our approach that we are in the present and you say that the present is privileged? Isnt this the question that is problematic for the spotlight view and drives people into B-Theory approaches? How do you deal with it? And what are you saying when you say that the present is privilieged?

RPC: Theres definitely a question here for the Moving Spotlighter that the B-Theorist doesnt face.  The first thing I do is make a defensive move: every A-Theorist faces this problem, not just the Spotlighter!  Presentists have tried to argue that they can solve this problem easily. Of course we are in the present, the thought goes: we exist, dont we? If everything is present, we must be!  But I think the presentist moves too quickly here.  If presentism is true, we are present, for sure.  But the truth of presentism doesnt thereby secure our knowledge that we are present.  Wed have to know that presentism is true.  And on the face of it, this is if anything harder to know than that we are present.  After all, to know that we are present our evidence has to rule out our being non-present.  But to know that everything is present our evidence has to rule out anything, including ourselves, being non-present.

So I think the presentist and the moving spotlighter are in the same situation here.  Each of them has a theory concerning what reality is like, and both those theories involve there being a privileged moment in time, and it is this moment- now ! The question is: why believe the theories?  But then were just in the normal business of weighing up the pros and cons of rival philosophical views.  So ultimately, my answer to How do you know youre present?’ is My theory of time says that we are.  And how do I know that that theory is true?  Well, I wrote a whole book arguing that its more beneficial than its rivals!

 Theres a lot more detail to the story than that. In particular, I have defensive moves to make against the charge that if the Moving Spotlight view is true then our belief that we are present is lucky or not formed by a reliable process. But if anyone is interested in the details of that, they should read Ch.1 of my book on the moving spotlight and my reply to critics (in particular to Kristie Miller) in Analysis Reviews.

3:16: Youve also looked at aspects of ontology. One issue youve addressed is whether there has to be a fundamental layer of reality one that blocks the turtles all the way down’ view. How should we look at this issue - which seems intuitively reasonable - and do you think there is a fundamental layer or not or is the intuition just some bug in our thinking? Is grounding real?

RPC: Grounding is real.  What it is is another issue.  Whether theres a single notion of grounding, as Jonathan Schaffer thinks, or whether there are a multitude of different grounding relations, as Jessica Wilson thinks, is a difficult issue - but that there is some phenomenon whereby some features of reality give rise to others is hard to deny.  Universities do not belong alongside electrons in physicistscatalog of the elements of being!

I think infinite descent - reality having no fundamental layer - is possible.  Maybe its even actual.  I think thats partly an empirical question.  I do think there is something beneficial about metaphysical views on which everything is ultimately grounded in a fundamental layer: there is a kind of explanatory benefit, a unity of explanation, that we sacrifice if we accept a world of infinite descent. I think that gives us a reason to believe in a fundamental layer, but its defeasible.  Empirical evidence and philosophical argument could yield reasons for infinite descent that outweigh this reason against.

These kind of issues are going to be the theme of my next book, Chains of Being, coming soon from Oxford University Press, so Ill leave it at that for now and hope you buy the book!

3:16:  Another ontological question you address is whether we can have a minimal ontology say, one that says only persons, abstracts and fundamental particles of a completed physics exist without saying that objects we think are real like cars, planets and cars are just errors of thought? 

RPC: One issue here is what the ontological question is.  Some philosophers have a very deflationary conception of ontology. Amie Thomasson, for example, argues that there is no distinctively metaphysical question to be asked concerning, e.g., the existence of tables.  There is a conceptual question: under what circumstances is the concept table appropriately deployed.  And there is an empirical question: are those circumstances met?  The former is a question of conceptual analysis, the latter a straightforward empirical question.  Theres nothing for the metaphysician to do!  I actually pretty much agree with Thomasson concerning questions concerning what exists.  But as a result, I think this isnt the question metaphysicians should be asking.  They should be asking: what is it in reality that makes true those claims concerning what exists?  Thomasson and I agree that tables obviously exist.  But I think (and she denies) that there is a further good (distinctively metaphysical) question to be asked: what makes it true that tables exist?  Do tables make that true, or atoms in the void arranged table-wise, or ideas in the mind of God, or etc.?  So for me, the project of defending a minimal ontology is the project of showing how a minimal collection of things can nevertheless make true all the things that are the case.  Planets and cars arent just errors of thought, they exist, and there are true things to be said about them.  But what makes those things true?  Maybe just atoms in the void.  So, at least, thinks the minimal ontologist.

3:16: Youve also looked at mereology the relationship of parts to wholes so whats your position regarding this? Do you think the facts concerning composition necessarily hold which is the orthodoxy at the moment and do you agree with the position that sees composition as identity?

RPC: I dont think the facts concerning composition necessarily hold.  One of my earliest papers - The Contingency of Composition - defended the unorthodox view that there is radical contingency with respect to when composition occurs: there can be two possible worlds identical with respect to what simples exist, how those simples are intrinsically and how they are arranged, but which differ with respect to what complex objects exist.  In general, I dont think very much is necessary.  Im a fan of contingency, and think a lot of stuff is contingent that metaphysical orthodoxy thinks is necessary.

I dont agree that composition is identity, although I think its a fascinating view.  I dont think it actually offers any big advantages over views that take the whole to be distinct from its parts, but where the parts ground or give rise to the whole, and so I dont think theres anything that makes it worth accepting many-one identity: an idea that I at least find very hard to accept.

3:16: Truthmaker maximalism claims that all true propositions without exception must have a truthmaker. Are you a Maximalist?

RPC: I am not, at least not in the sense that would make David Armstrong happy!  I think every truth must be made true by reality, but I deny the distinctive claim Armstrong made: that for every true proposition there is some thing whose mere existence necessitates that that proposition is true.  I think that that principle is too strong (although I have written papers defending it in the past).

3:16: Vagueness is something youve thought about you seem to agree with the arguments of Williamson that classical logic and bivalence shouldnt be junked and that therefore a sharp cut off in a sorites is ok. So  are you an epistemicist regarding vagueness ie that the indeterminism of vague cases is due to some species of ignorance?

RPC: I actually reject classical logic and bivalence.  I think that both truth-value gaps and truth-value gluts are possible: that is, claims that are neither true nor false, and claims that are both.  As such, I accept a logic much weaker than classical logic: the logic known as First Degree Entailment.

But, I donthink that vagueness is a case where we should see gaps or gluts.  So I dont think the sorites paradox is a reason to abandon classical logic or bivalence.  If we have a sorites series starting with a completely bald man, followed by a man with one hair on his head, followed by a man with two hairs on his head, and so on, I think there is a first point at which there is a bald man standing next to a non-bald man.  However, I am not an epistemicist, because I think that it is metaphysically unsettled who the first non-bald man is.  So unlike Williamson, I dont think that it is simply a matter of our (in principle) ignorance of where the cut-off is, I think that reality itself doesnt settle where the cut-off is.  It is metaphysically determinate that there is such a cut-off, but metaphysically indeterminate where that cut-off is. Indeterminacy and vagueness, for me, are not epistemic phenomena, they are metaphysical phenomena.  (I am married to one defender of metaphysical indeterminacy - Elizabeth Barnes - and am good friends with two others - Robbie Williams and Trenton Merricks - so it was inevitable I caught the bug.  I hasten to add that they shouldnt be blamed for what I do with it!)

3:16: You ask a great question so Ill just repeat it for you to sketch your answer: whats metaphysical about metaphysical necessity?

RPC: In the paper whose title is that question my answer is: not much!  That is the first of a few papers in which I defend a very deflationary conception of necessity: a kind of conventionalism (similar to the view defended by Ted Sider), but one which abandons the notion of truth by conventionthat traditional conventionalist made use of, and which was attacked by Quine (et al).  But while I like the view and thought it should be defended, I cant say I actually sign up for it.  I suppose if I have to place my money on a view as to the source of metaphysical necessity, Id bet on something like Kit Fines view, where what is possible is what is not ruled out by the essences of things.  On that view, modal facts have their ultimate source in essentialist facts.  So whats metaphysical about metaphysical necessity?  Lots! 

3:16:  I'm introducing a new feature - hopefully it's quick! One word answers please unless you want to explain something - 

 Q: Ethics: realism or anti-realism?

 A: Realism. Hard core, table-thumping, no apologies Realism!

 Q: Ethics: deontology, consequentialism, or virtue ethics?

 A: Virtue ethics if I have to choose.  Definitely not consequentialism.

 Q: Abstract objects: Platonism or nominalism?

 A: Platonism! No, nominalism.  No wait, Platonism.  Hmmm . . .

 Q: External world: idealism, skepticism, or non-skeptical realism?

 A: In my heart of hearts: skepticism.

 Q: Free will: compatibilism, libertarianism, or no free will?

 A: Compatibilism

 Q: Naturalism or non-naturalism?

 A: Non-naturalism.  (Or maybe I dont think the distinction is well-defined.)

 Q: Truth: correspondance, deflationary, or epistemic?

 A: I dont think there is a good question to which these are rival answers.  (Sorry . . . typical philosopher answer!)

 3:16: And for the readers here at 3:16, are there five books you can recommend that will take us further into your philosophical world?

RPC: Im going to ignore the really obvious stuff (if you know anything about the issues I work on, you can probably guess that I read a lot of David Lewis, Ted Sider and Kit Fine): so here are 5 recent books that are important to me that might not be super obvious from looking at my CV:


Amie Thomasson, Ontology Made Easy


Robert Pasnau, Metaphysical Themes 1274-1671


Sarah Moss,  Probabilistic Knowledge 


Hud Hudson, The Metaphysics of Hyperspace


Kris McDaniel, The Fragmentation of Being


Richard Marshall is biding his time.

Buy his new book here or his first book here to keep him biding!