On Philosophy

March 26, 2007

What Are Properties?

Filed under: Metaphysics — Peter @ 12:00 am

Defining what, exactly, is a property is a harder task than you might think. Of course on the macroscopic level the task is relatively easy, a property is just a kind of similarly between objects. And an instance of such a property is simply whatever features in a particular object are responsible for that similarity. For example, things are macroscopically red because they reflect similar wavelengths of light, and the instantiation of redness in each of them is whatever is making them reflect those wavelengths (usually some feature of their surfaces).

But ultimately these macroscopic similarities and macroscopic properties are reducible to more and more fundamental properties, which we appeal to in describing the similarity between two objects. Ultimately we reach the fundamental physical properties, and since these fundamental physical properties are not reducible further they are not so easily explained by an appeal to similarity, as we can’t give a reason as to why two fundamental constituents are similar except by appeal to the very property we were trying to explain in terms of that similarity. What makes the property of having a certain spin value the same property in two different fundamental particles?

One way to resolve this problem is to define a property as the set of objects which we say have that property. Thus the property of having a certain spin value would actually be the set containing all the fundamental particles with that property. And we could thus explain why two particles have the same property, or at least systematize it, by appealing to the fact that they are members of the same property set. Of course why the particles belong to the sets that they do may still seem like an open question, but at a certain point our explanations must simply bottom out. Ideally we would like to appeal to natural law, but unfortunately natural law doesn’t seem to deal with sets.

The other option is to identify a property with its causal effects. Under this definition of properties two particles have the same spin because they have the same causal effects, or, more precisely, the same causal dispositions. Under this definition of properties natural law does, in some sense, underlie the fundamental physical properties, because all it means to have such a property is to have certain causal effects, which means being part of a certain kind of regularity, which is what we call natural law.

Neither definition may seem inherently better than the other at this point, so let’s consider how we can tell if two objects have the same property given these definitions. If we can’t determine whether two objects have the same property then clearly we are dealing with a poor understanding of what a property is, because if properties can’t be distinguished from each other then it would seem that they aren’t doing any explanatory work, and hence aren’t a good description of the world. And indeed defining a property as a set of objects fails by this criterion, because there is no way for us to determine if two objects belong to the same set, since we don’t have access to these theoretical sets. In theory there could be a nearly infinite number of properties that all had the same causal effects, and we wouldn’t be able to tell them apart. Thus identifying properties with causal effects may seem like a better choice. But how can we tell when two things have the same causal effects? Certainly we can’t appeal to a similarity in results, since that relies on us being able to tell what properties those results have, and here we are trying to establish that we can tell properties apart from each other, so such a definition would be circular. But there is a way out of this problem, by appealing to an observer of those effects. An observer, in this context, is simply a system with a memory, the ability to compare its internal states, and that ability to be put in various states by external events. We can define what it means to have the same causal effects then by saying that an observer sensitive to those effects would think that they effects of both were the same (the observer judges that the state it is put into is the same in both cases). Of course in real life any observer may make mistakes, but here in our definition we can appeal to a hypothetical ideal observer. And thus we have a way to tell causal effects apart, and thus a way to tell properties apart given that they are identified with causal effects.

Thus I favor identifying properties, at least the fundamental ones, with causal effects. Such a definition, as shown above, allows the distinctions between properties be meaningful instead of arbitrary. Furthermore, it makes the properties themselves a byproduct of the regularities of nature instead of a cause of them, meaning that properties would thus be a description of the world, as they should be. In contrast, identifying properties with sets would seem to make them a kind of framework that the world is built on, and, moreover, would make the sets themselves physical objects, since they would part of the causal explanation of why particles behave as they do. Not only does this seem implausible, but physics just doesn’t seem to be heading in that direction. And thus the identification of properties with causal effects seems like a better treatment of them on several levels.



  1. I like the direction you’re moving in here, especially the idea of an “ideal observer.” While obviously, there is no such thing, reasoning about an ideal observer allows us to give metaphysics and epistemology separate footings.

    Combining this with your last post, do we really need to believe that an electron is anything other than the condition of reasonable inference of an electron? In other words, the causal inferences don’t just tell us about the existence of properties, but of the particles in which the properties are thought to inhere as well.

    Saying, “there’s an electron over there,” means, “if you look there, the causal patterns indicative of the properties of an electron will arise in the observer.” Similarly, saying, “there’s a cup on the table,” means, “if you go to the table, then you will under go the causal states normally associated with cups, viz. you’ll see a cup-shape; if you try to touch it, it will push back; etc.” (Actually, more to the point, in Heideggerian vein, we can say, “there’s something that can be used as a cup due to its apparent causal effects,” but that’s basically the same thing.)

    Comment by Carl — March 27, 2007 @ 3:17 pm

  2. This is all so very interesting, but i have been spending too much time at:


    Check it out when you have time!

    I have a question: I’m wondering why nothing was mentioned about Heisenberg and his uncertainty principle?

    —The Brat!

    Comment by Robert Darrell — March 27, 2007 @ 8:08 pm

  3. All the uncertainty principle says is that we can’t know exactly what properties of position and velocity something has, that we can only deduce that they are within a certain range depending on the size of the object and how we are measuring them. Which has epistemological consequences, but not really metaphysical ones.

    Comment by Peter — March 27, 2007 @ 11:58 pm

  4. Yes sir, you are quite right. You epitomized the principle in a nut shell!
    I still have to study Yours and Carl’s articles because I’m not well versed —what I lack in understanding interpretation I make up for it in “visual imagination” if I can.”

    And speaking of “visual imagination” I have an idea. Tell me, if you kindly would, what you think of it….

    Imagine a particle spinning in an orbital fashion. For visualization’s sake, it’s spinning around a column (like one of the columns of pantheon).

    While this particle is spinning, your sitting on top of it for the ride.

    Before you clime aboard, make a dot on the column with your pretend magic marker: That will be your staring point. Now your spinning on a particle and the dot shows up in intervals.

    Here’s the interesting part: If you spin fast enough, you get closer to the starting point where you had just left rather quickly! You would see yourself getting closer to yourself. You would see yourself from behind. It takes a crazy imagination to appreciate where I’m going with this. It is so impossible to assume that you would eventually bump into yourself? More astounding is, if this conceptual event is even possible, then are we not talking infinity here?—because the particle would meet itself at every “moment” (a circle has infinite arches)!

    The idea, to me, is a joy-gasm.

    (The concept is even better when you think of a sphere spinning at that rate: The variables are astounding!)

    If you suddenly occupy the spot where you had just left, then you are not spinning fast enough—if you spin fast enough, then eventually you occupy the same space in which you occupy, as though you hadn’t left, in the form of a circle [infinity]. (I can see a lot of time/velocity annoyances taking place here, what I mean is, if the experiment is to be at all tidy, it would have to take place in a closed system that is perfectly stationary—but the idea is more beautiful if the experiment in the system is moving in an alternate direction.)

    I can’t help imagining what happens next! Does it kick-start perpetual motion? Does a particle “copy” itself in this circumstance? If so, where does it go?—in another dimension? Could that perhaps be what happened at the singularity big-bang? Would that be the essence of radiation? Is all matter derived from a single particle making copies of itself, in that fashion, in an instant of the big-bang?—Or explain why the universe appears to have more than one electron?—Or explain the possible existence of the tachyon? Would this concept in any way have anything to do with the flow of one or more types of time dilation (parallel types)? Would such a process better explain the eternal abundance of “irrational numbers”?


    I want you to know that I’m the nut that thought of this simple concept. So I’m the one to blame for its absurdity. ( if some else did, then who? I want to read about it)

    I want to say just one more thing. I’m always thinking about what consciousness really-really is…something about it we never considered. And I’m getting close. I’m almost there!

    I think I think, therefore I think, I think! lol!

    I’m going to stop here for now because there’s other things I want to do today.

    Thank-You for a really great website! You and Carl are brilliant!

    PS: I have more crazy entertaining ideas, but I’ll save them for later.

    —The Brat!

    Comment by Robert Darrell — March 28, 2007 @ 8:47 am

  5. Are we ignoring the speed of light?

    Comment by Peter — March 28, 2007 @ 11:02 am

  6. Indeed.

    When I was a kid I wondered why the blades of a fan seem to disappear at higher speeds. The reason is that the eye and brain don’t bother to track things that happen faster than a tenth of a second. So, if during first half of the exposure time the background is visible and during the second half the background is blocked by a fan blade, those two images will be composited together like a double exposure photograph or a Photoshop transparency.

    Now, what if you could ride on a fan blade? Well, as long as your fan doesn’t rotate at an appreciable fraction of the speed of light, you’ll just see one of the other fan blades steadily in front of you and the third behind you, but the outside world will be a uniform blur that mixes everything you would see on a single slow speed rotation together.

    Now, obviously, a human can’t ride a fan blade because we’re too heavy and we’d pass out, but you can try taping a small digital camera (and counter weights for balance) to a fan to test the hypothesis. I’m confident it will come out as I predict: the fan blade is no close to itself or the other blades, but the background is a solid blur.

    Comment by Carl — March 28, 2007 @ 1:33 pm

  7. I asked myself the same question. Before I share my point of view on that, I have a few matters of concern.

    When we say that light travels 180 thousand (or whatever it is) miles per second, I get a very nauseous headache! Here’s why…

    “Per Second” is a man-made concept. A “second” in time, according to my childish brain power, is basically an ‘average’ between the marriage of time (so-called fourth dimension) with distance and velocity—depending on the magnitude of the gravitational field you happen to be subjected to from where you’re conducting your observation. The speed of light, as far as I am concerned, is not exactly universal, is my point. If the gravitational field of a black hole prevents light from passing through, then how can light be considered a god-dam ‘constant’? ? ?

    Now, if a black hole compresses space-time, what ever becomes of the size and speed of the photon? If coal is turned into diamond under pressure, what does light turn into under pressure? Another kind of light maybe? Tachyon, perhaps? Dark Matter? (I have a theory that the material of an extraterrestrial’s space craft’s shell is primarily made of extremely compressed water that is so compressed so so so deeply, that it can’t be returned to it’s former state, but remains metallic) but whatever!

    In answer to your question: No! We do not ignore the speed of light—What we should ignore is the matter of fact behavior we always expect of light, especially under conditions in which we do not fully understand—or find absurd (like squaring light into Pi, for instance).

    Try this: Imagine traveling along side a photon. It should appear to be at rest. Next, suppose as you’re traveling along side this photon, that you have the instrumentations that enable you to spin the photon in a circular motion at the speed of light! (ever notice when you spin a square it becomes a circle?). If you spin it close to the speed of light, and light cannot go faster than light, would not light traveling at the speed of light change constituent form and speed when spun as fast as it traveled?

    Peter, I really want to share more with you because this is a lot of fun! I would like to wait and hear what you have to say—and I know there are technicalities, but it is not in my nature to allow ideas to be put to rest simply because we believe them to be the definitive holy grail! . I don’t think in those terms, because if I did, I would be bored, unresponsive, and I wouldn’t be a philosopher nor a bratty theorist!

    We are like the fish in the sea, we see the surface, and maybe a glimpse of the sky; find a way out of the sea and then the moon is ours!

    Comment by Robert Darrell — March 28, 2007 @ 1:35 pm

  8. My point was you can’t go as fast as you would like in a circle because you can’t go faster than light.

    Also we wouldn’t expect photons to change shape udnder “pressue” because they are point particles, and hence can be packed together arbitrarily closely as they are.

    Finally, a photon cannot be “spun” because since photons are moving at the speed of light they don’t “experience” time. (The photon’s frame of reference is infinitely time dilated.) Thus they can’t rotate as that would require time to pass in the photon’s frame of reference. Or in other words the photon can only rotate infinitely slowly, which is a fancy way of saying it can’t rotate.

    Comment by Peter — March 28, 2007 @ 1:51 pm

  9. “Try this: Imagine traveling along side a photon. It should appear to be at rest.”

    If you say that, then you haven’t fully understood Einstein’s theory yet. It’s worth reading more about it until you fully understand it before bother to launch out on fresh speculation. Remember that many physicists have attempted to come up with alternate theories of motion and gravitation, but Relativity has passed every test we’ve made of it, and no one has yet succeeded in displacing Einstein.

    Comment by Carl — March 28, 2007 @ 2:21 pm

  10. Carl!
    The fan blade is not traveling fast enough! it’ the world the fan blade is made of that intrest me is what i’m refering to!. Think of regions of the infinately small! Think quantum!
    If we could possably harness gravity, and make the space within and around our ship as small as Pi-mason, while maintaining the intergrety of our suroundings to sustain the pilots, then I’m more than sure we can travel acroos an ocean of galaxys, even through matter itself, in the blink of an eye, because the rules are different in sub-space! There’s other demensions out there!
    The technology we have right now is like a caveman inventing the tooth pick.


    Comment by Robert Darrell — March 28, 2007 @ 2:26 pm

  11. Excuse me, but einstien said, and i read thit in a physica book, that if you travel along side of light, “YOU WOULD SEE AN OCCILATORY MOTION AT REST”!!!!!

    Comment by Robert Darrell — March 28, 2007 @ 2:28 pm

  12. you need to go back and read einstine!!!

    Comment by Robert Darrell — March 28, 2007 @ 2:29 pm

  13. ARG!

    Comment by Robert Darrell — March 28, 2007 @ 2:34 pm

  14. CARL, i have to help with the dishes…Be right back!

    Comment by Robert Darrell — March 28, 2007 @ 2:36 pm

  15. ok….I am going to have to do some research. “Photons dont experience time”

    I never heard of that!

    point particals?

    I’m going to have to read more of your work, Peter, because I want to know!!!

    Comment by Robert Darrell — March 28, 2007 @ 2:53 pm

  16. Is a photon a timeless world traveling through time?????

    Comment by Robert Darrell — March 28, 2007 @ 2:55 pm

  17. Peter, I pasted your responce to my page so my friends can see it.


    Comment by Robert Darrell — March 28, 2007 @ 3:11 pm

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