To: Andrew A.
From: Geoffrey Klempner
Subject: Abstract vs concrete, possible vs actual objects
Date: 17th September 2010 12:03

Dear Andy,

Thank you for your email of 9 September, with your first essay for the Metaphysics program, in response to the question, 'Give everyday examples illustrating the difference between 'abstract' and 'concrete' objects, and also between 'possible' objects and 'actual' objects. What philosophical questions arise from this four-fold classification?'

This is a very competent essay, which shows that you have grasped important lessons from both the Philosophy of Language and Metaphysics programs. (On a historical note, a significant amount of material from both programs derives from my Oxford D.Phil thesis - in particular the stuff about the Realist/ Anti-Realist debate.)

Is 'Roy of the Rovers' an abstract object? That's a good question because the answer doesn't occur to me immediately. There are, of course, 'impure' as well as 'pure' abstract objects. Pure abstract objects would, as you put it, 'exist in a void' (a perfect example being the null set, the set containing the null set, the set containing the set containing the null set, and so on).

So Roy of the Rovers would be an impure abstract object. But he is not a set. (If he was a set, what would he be a set of, all the comic stories in which Roy of the Rover appears? Without doubt Roy of the Rovers exists if and only if the set of all the stories in which he appears exists, but that doesn't *make* that set the same 'object' as Roy of the Rovers - not least because there are other characters who appear in those same stories. Or maybe you can think of a better candidate for the requisite set?)

Roy of the Rovers is a possible object, if you allow that there is a possible world - or, rather, a set of possible worlds - where all the Roy of the Rover stories describe the historical truth. As a possible object, he is a possible *concrete* object. (The non-empty set of all my snooker trophies is a possible, but not an actual impure abstract object, dependent for its existence on the existence of possible concrete objects, viz. my snooker trophies.)

I am tempted to say that Roy of the Rovers is a counterexample to the claim that concrete/ abstract actual/ possible exhaust all the possible ways of being an 'object'. In other words, the persons or objects which occur in fiction - or myths, legends etc. - are from an ontological standpoint sui generis. They are more than just (impurely) abstract or possible objects. They have a 'life' of their own, given to them by the human penchant for storytelling, by their influence and importance in human culture. Maybe 'cultural artefact' would do, but then one would have to distinguish them from things like novels, musical compositions, images etc.

The point about 'ontological relativity' is inspired by the Philosophy of Language program, where there is some discussion of W.V.O. Quine's views (e.g. in 'Ontological Relativity and Other Essays'). I always feel queasy about this. If we take Quine's point as the literal truth, then there are no concrete objects, as such. 'Socrates is wise' is no different, in its empirical content, from 'Wisdom Socratizes'. Yet we *know* that there is a story to tell in terms of causes and effects (a point you make earlier in relation to abstract objects) which accounts for our being justified in attributing wisdom Socrates. How does that story go, if instead one is attempting to explain how we are justified in attributing the property of 'Socratizing' to Wisdom?

It is not enough to re-interpret the symbolism for identity and individuation: one also needs to re-interpret the symbolism for describing the relation between cause and effect. Provided one carries through the re-interpretation consistently, then ontological relativity holds. But that still leaves me feeling queasy.

A lot of students taking the Possible World Machine (the most popular of the 6 Pathways programs) baulk at the idea that possible worlds are 'real', each existing in 'its own' space and time, so that the difference between possible and actual worlds is, as you describe, merely a consequence of perspective. We cannot 'leave' the perspective of our actual world in order to attain a God's-eye view. In Ch.18 of 'Naive Metaphysics' I describe a way to habilitate (or rehabilitate) possible worlds, along the lines of the 'clash' between the 'subjective' and 'objective' worlds. There is an 'irresolvable contradiction', which arises in the first place because of our (my) inability to get outside our (my) own perspective.

But does that seriously mean that there is a sense in which Roy of the Rovers is 'real', somewhere 'out there', as the foremost defender of realism about possible worlds David Lewis claims? Another thing to feel rather queasy about.

All the best,

Geoffrey