mercredi, juillet 20, 2005

Is There Daylight between Existence and Non-Existence?

By Uriah Kriegel
A discussion from another blog

Consider Jim, Jim’s shadow, and Jim’s ghost. According to common wisdom, Jim is a real thing, Jim’s ghost is not, and Jim’s shadow has some sort of intermediate status (“lower” than Jim’s but “higher” than Jim’s ghost’s). Perhaps the folk would say that Jim’s shadow is real alright, but it is not quite a thing.

Philosophers, however, tend to push us to choose between putting Jim’s shadow in one category with Jim’s ghost or in one with Jim. The notion that existence may have three rather than two ‘states’ or ‘values’ is deemed unintelligible. And with good reason: the notion seems mysterious. But I can’t shake my feeling that at the end it must be right.

I’m thinking about this in connection with the disputes going on about the status of artifacts and other ‘medium-sized dry goods’ (MSG). On the one hand, some people (e.g., Heller) hold that only subatomic particles exist, and the MSG don’t. On the other side, some people (e.g., Thomasson) hold that the MSG exist just as much as subatomic particles. I have a vague feeling that if we had a general account of the ‘intermediate ontological status’, it would apply nicely to the MSG and may be a satisfactory compromise.

(I’m told that Sidelle’s view goes something like that, and maybe Chisholm had similar things to say, but I’m not familiar with the relevant material.)

This entry was posted on Thursday, July 14th, 2005 at 12:00 am and is filed under Metaphysics .

Responses to “Is There Daylight between Existence and Non-Existence?”

Tony Marmo Says:
July 14th, 2005 at 5:52 am

In which sense Jim’s shadow would be equiparable to his ghost? A shadow is an effect of light against his physical body. It exists as a phenomenon, but it is not Jim. Jim’s ghost to those who believe in ghosts would be Jim after death. Perhaps, you use the word shadow in another sense.

Stargazer Says:
July 14th, 2005 at 8:48 am

It all depends on what the definition of ‘is’ is.

Plato and Aristotle, for instance, would count Jim’s shadow as less of a being than Jim because each defines ‘being’ in such a way as to diminish that of the shadow. The being of the shadow is derivative of the ‘really real’ (universal form or individual substance respectively).

For my part, I see no reason to deny that the Jim and his shadow are equal with respect to their existence. Qua being, as they say, what does Jim possess that his shadow lacks?

What is Heller’s rationale for denying existence to physical complexes? And what claim do subatomic particles have on simplicity (for that matter, what is meant by ’simplicity’)? They are not physically simple? Even something like Hertz’s point-masses don’t seem to be physically simple. They have parts in the sense of dimensions, i.e., they have sides — it makes sense to say that I am to the right or to the left of a point-mass.

Tony Marmo Says:
July 14th, 2005 at 1:31 pm

Yeah, you got right on the target, Stargazer. I have roughly had the same kind of questioning in my comments on paper about the (in-) existence of artistic work ( The Destruction Problem ). Which is to say, we all have to agree that when we think of sub-atomic particles and Quantum Physics in general, most of our notions about existence are challenged, like the one (repeated by Barber and Caplan) that something comes to existence at a certain (determinable) point-instant, etc.
Briefly, if I can make myself clear, we cannot pretend to be still in the 18th century and play the naive guys, as if we still lived in an Euclidean Universe where Classical Physics rule. Everything that seemed common sense back there has been already put upside down, sort of say.

Jeff Medina Says:
July 14th, 2005 at 8:36 pm

To Uriah:
Jim’s shadow is a area of lesser electromagnetic reflectivity relative to the surface adjacent to its boundaries. Unless you feel like saying electromagnetic waves don’t exist, or somehow ‘exist less’ than Jim or Uriah or Jeff, how is it that a shadow, which can be exhaustively defined in terms of various things which we agree exist (Jim, a light, a surface), might be said to have less than full existence?

To Stargazer:
It doesn’t make sense to say you’re to the left or right of a point-mass in any objective sense. “To the left of” is utterly dependent on orientability (having a distinct ‘front/back’, relative to which left & right are defined — cf. the perfectly sensible question “Your left or my left?”, which is only asked when the two persons are differently-facing).
Point-masses have no fronts or backs, and hence no left & right, so it only seems to make sense to say you’re to the left or right of a point-mass by way of transposition — you note that the point-mass is to *your* right, and hence by default *you* are to *its* left. But that’s just anthropomorphic error, not anything informative about point-masses.

Stargazer Says:
July 15th, 2005 at 7:45 am


I don’t see that “dependence on orientability” is of any relevance here. Let’s dispense with talk of right and left. Consider the following example: a point-mass X is between John and Jane.

If point-masses did not have sides (i.e., if they didn’t have a surface, if they didn’t have extention), then it would not make sense to say that John is on one side of X and Jane is on the other. That is, using X as a point of reference, it would be impossible to give the relational positions of other objects.

It is my (humble) opinion that an “extensionless physical point” is mere nonsense (on a par with 11-dimensional “space”). Any physical body has extension.

Stargazer Says:
July 15th, 2005 at 7:48 am

Make that “extension” throughout.

Jeff Medina Says:
July 15th, 2005 at 8:15 am

Stargazer said, “a point-mass X is between John and Jane”
“If point-masses did not have sides […], it would not make sense to say that John is on one side of X and Jane is on the other.”

Given two objects, A & B, a third object, P, is said to be between A and B iff there is a straight line, AB, connecting A & B, that intersects with P.

This definition works for both mathematically precise & physical uses of “between.” (Although the physical usage loses precision on occasion due to human error & approximation.)
The mathematical application of this definition works perfectly well for *points defined in mathematics as 0-dimensional*, and you’d be laughed out of the room if you told a group of mathematicians that a point P wasn’t between two N-dimensional objects (for N in the non-negative integers) because to be between two objects, P has to have sides.

So either your intuition is off — “extensionless physical point” is not nonsense at all (or, if it is nonsense, it isn’t for the reasons you’ve stated) — or you’ve proven not only that all physical point-masses have extension, but also that vast amounts of mathematics are fundamentally flawed for assuming 0-dimensional (extensionless) points can rest directly between two other propertly placed mathematical objects. This mathematics would have to be thoroughly revised, should you be correct; a revelation matching Gödel’s or Weil’s in significance.

Stargazer Says:
July 15th, 2005 at 8:43 am

Jeff writes: “So either your intuition is off — ‘extensionless physical point’ is not nonsense at all (or, if it is nonsense, it isn’t for the reasons you’ve stated) — or you’ve proven not only that all physical point-masses have extension, but also that vast amounts of mathematics are fundamentally flawed for assuming 0-dimensional (extensionless) points can rest directly between two other propertly placed mathematical objects.” There is a third possibility. Let me reply illustrate it with the following quote from Wittgenstein’s Blue Book:

It might be found practical to call a certain state of decay in a tooth, not accompanied by what we commonly call toothache, “unconscious toothache” and to use in such a case the expression that we have toothache, but don’t know it. It is in just this sense that psychoanalysis talks of unconscious thoughts, acts of volition, etc. Now is it wrong in this sense to say that I have toothache but don’t know it? There is nothing wrong about it, as it is just a new terminology and can at any time be retranslated into ordinary language. On the other hand it obviously makes use of the word “to know” in a new way. If you wish to examine how this expression is used it is helpful to ask yourself “what in this case is the process of getting to know like?” “What do we call ‘getting to know’ or, ‘finding out’?” It isn’t wrong, according to our new convention, to say “I have unconscious toothache”. For what more can you ask of your notation than that it should distinguish between a bad tooth which doesn’t give you toothache and one which does? But the new expression misleads us by calling up pictures and analogies which make it difficult for us to go through with our convention. And it is extremely difficult to discard these pictures unless we are constantly watchful; particularly difficult when, in philosophizing, we contemplate what we say about things. Thus, by the expression “unconscious toothache” you may either be misled into thinking that a stupendous discovery has been made, a discovery which in a sense altogether bewilders our understanding; or else you may be extremely puzzled by the expression (the puzzlement of philosophy) and perhaps ask such a question as “How is unconscious toothache possible?” You may then be tempted to deny the possibility of unconscious toothache; but the scientist will tell you that it is a proved fact that there is such a thing, and he will say it like a man who is destroying a common prejudice. He will say: “Surely it’s quite simple; there are other things which you don’t know of, and there can also be toothache which you don’t know of. It is just a new discovery”. You won’t be satisfied, but you won’t know what to answer. This situation constantly arises between the scientist and the philosopher.

It seems to me that, whatever the mathematician is talking about with “0-dimensional points”, he is not talking about physical points.

Uriah Says:
July 15th, 2005 at 4:26 pm


Here’s the worry about a shadow, or one way to articulate it. A shadow is not an abstract entity. But it also doesn’t have spatial volume - it doesn’t take any space. How can a non-abstract entity exist without taking any space?

Relatedly, the shadow doesn’t have any proprietary causal powers. It has inherited causal powers (e.g., to cause perceptions of shadow), but no non-inherited ones. Some would argue that no entities should be posited that do not bring into the world new causal powers. If so, the shadow doesn’t exist.

Tony Marmo Says:
July 16th, 2005 at 12:59 pm

This reminds me of the title of a recent paper by Mark Sharlow, I am an Abstraction, therefore I am (which I cannot link to because Sharlow asks People not to redistribute), perhaps a ‘post-modern version’ of Descartes’ Cogito, ergo sum.

Well, Uriah, in Optics things are not exactly like that. When you look at some image in a mirror you see objects not only in perspective (like in a painting), you see distance, which is in elementary Physics called virtual distance. Yet there is no volume, unless you want to talk about virtual volume. The image works just like the real object. This makes a lot of difference, e.g.: people affected by myopia, when they take out the spectacles, know that if they look at a painting with perspective they can still see everything in the painting, if they look closely. However, if they, without their spectacles, look closely at ta mirror, they will not be able to see the reflection of the distant objects, just like if they looked at the so called real things.

What is the image of something in a mirror? It is an effect of the laws of Optics, certainly. Does an effect exist? Shadows result from the refraction of light, when light cannot pass throughout something opaque. Does the effect of refraction exist? I think it depends on how Optics fits into your conceptions of existence. But I shall let the Physics experts speak their minds.

Brian Says:
July 18th, 2005 at 3:16 pm

Tony may be onto something in bringing mirror images into the thread. Shadows and reflections are similar in at least one important way, and thinking about the analogy may shed some light on the shadow problem (yuk yuk).

Uriah writes: “How can a non-abstract entity exist without taking any space?” Neither Jim’s shadow nor a Jim’s reflection takes up any space. However, both the shadow and the reflection require the existence of some object that itself takes up space. A reflection can’t exist without a reflector, and a shadow can’t exist without being cast onto some surface. Perhaps we ought to think about shadows and reflections not as objects in their own right, but rather as modes, states, or properties of the objects onto which they are cast. In this spirit, I submit the following.

When I look at myself in the mirror, I see only two things: the mirror, and myself. I do not additionally see a third thing, ‘my reflection,’ over and above myself. Similarly, when Jim’s shadow is cast onto the ground, there are two things: Jim, and a darkish Jim-shaped patch of ground. There is not a third thing, “Jim’s shadow,” over and above the patch of ground onto which it is cast. These mysterious ‘third objects’ are mere illusions.

Audiences attending early motion pictures fell prey to the same kind of illusion. Indeed, the illusion is what made movies so thrilling. It was as if Charlie Chaplin (for e.g.) were right there, moving around inside the screen. But no one was in the screen. Charlie was lounging in his Hollywood home, and the cleverly illuminated screen hung motionless.

On this view, we might say that “Jim’s shadow is real alright, but it is not quite a thing.” The shadow is not an object, but rather a state or property of the ground. I’m not sure how or whether this fits with the artifact/MSG debates, of which I am ignorant. Probably I’m way off the mark.

Uriah Says:
July 19th, 2005 at 11:16 pm


Welcome to our humble blog! I like your analogy, and I think it lends support to the thesis that shadows don’t exist. Reflections don’t exist, and part of the way to appreciate this is to note, as you do, that when I see myself in the mirror I don’t see two object, a person and a reflection. Rather, I see a person by seeing a reflection, just as Berkley hears a coach by hearing its sound, without it following that three are two objects heard.

(I don’t actually hold that shadows don’t exist. I’m just trying to motivate the idea that ascribing existence to them is problematic.)