Stephen Mumford: Can We Know Powers?

Thanks to Stephen for this post!

* * * *

A problem that has troubled me for some time concerns our knowledge of powers. Powers are supposed to be perfectly naturalistic elements of our world and accordingly should be epistemically accessible in theory. This is important for a couple of reasons. One is that we need to respond to Hume’s view that we can have no notion of power over and above constant conjunction, which is what he thinks we experience. And those who enthuse about powers do so partly because, contrary to what Hume says, they think powers are familiar to us. This provides an alleged advantage over those metaphysics that depend on other possible worlds, all of which are – as the theory accepts – epistemically inaccessible to us.

A possible hitch, though, is the argument that powers are themselves unknown. All we can really know, goes the objection, are the manifestations of those powers.  One of the basic moves of the powers theory is to distinguish sharply between the powers and their manifestations. Powers are directed towards their manifestations, in some sense, and can exist without them. We can see that the glass is broken or the sugar is dissolved; but can we see that these things are fragile and soluble? Perhaps not. A force may push against your body; but arguably it is only the manifestation of the force that you feel, not the force itself. And if we concede that it is indeed only manifestations that are experienced, rather than the powers, then we seem to play into Humean hands. They are the ones who tell us that only the events exist: no hidden powers behind them, generating them. So if we concede that we have no experience of the powers themselves, the Humean can invoke their old argument that we have no right to speak of powers as anything over and above the pattern of events we experience.

I offer two thoughts on this issue, from the viewpoint of a friend of powers. First, maybe the powers just are theoretical postulates lying behind their known manifestations. But that shouldn’t in itself condemn them. It just means that their status as entities is metaphysical and, like anything else metaphysical, we should believe in their existence on metaphysical rather than empirical grounds. It is arguable that powers can be known to exist if there are valid metaphysical arguments for their existence. A realist metaphysicist is unlikely after all to say that empirical evidence is the only good ground for belief in something.

I think this first response is certainly attractive but it doesn’t really address the concern. In particular, there was a claimed advantage of powers over possible worlds, but they now look to be in the same epistemic boat: known only as theoretical postulates, justified in terms of their explanatory role.

The second point might get more to the heart of the matter. It seems unfair to treat the powers standing behind manifestations as entirely epistemically unknowable when the grounds for doing so would not usually apply to other known entities. Powers are known through their effects, in this case their manifestations; but so is everything else and we don’t take that as a compelling reason for general scepticism. So if we reason that a power cannot be known, only its manifestation, shouldn’t we argue that a table cannot be known, only its effect on our senses, and the same for every other thing we perceive?

Perception occurs through the perceiver being causally affected by the object of perception; in other words, things are known through their effects. Beliefs in unperceived objects and in substances as causes of perceptions are thus metaphysical beliefs, inferred from the effects that such objects have on us in perception. Yet the experiences caused in us by a table, for instance, are as good empirical grounds as any to say that we have knowledge of the table: not just knowledge of the effects of the table. This seems sound reasoning especially if you have a broadly Eleatic view about the nature of existence. To be real is to be causally powerful and to be known empirically is nothing more than to enter into some kind of causal relation with a knower: to affect it. Being affected by something is thus an essential part of the story of what it is to know it. Just as one knows a table from its manifestations, shouldn’t we say the same of all powerful entities: they are known by their effect?

What, then, of the powers themselves? Are they to be excluded from this thinking because they are the things standing behind and causing experiences? I am not sure that is fair. And should we then concede to the Humean that they are right that the world consists of nothing but a pattern of manifest events? This move still might be resisted. To say that manifestation in perceptions is the way in which a thing is known is not to say that the thing is nothing but those manifestations in perception. That seems to be the fallacy committed in phenomenalism about objects, such as in Berkeley’s system. If the proposed analysis is right, then it seems at least a possible position to allow that powers are known and experienced, through their manifestations, but are nevertheless distinct from those manifestations. I confess that my thinking on this topic remains incomplete.

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3 Responses to Stephen Mumford: Can We Know Powers?

  1. rgroff2013 says:

    Hi Stephen! Thanks again for this post. One nice thing about being the admin of the blog is that I don’t have to feel guilty about commenting all the time. Your post makes me think a few things.

    First, I’m pretty sure that I think that we shouldn’t take powers and their manifestations to be different things, even if we can distinguish between an expressed power and an unexpressed one as different states. I want to say that a power just *is* the kind of thing (note: all metaphor! — powers are not things; they are something like “the kinds of doing of which phenomena of different kinds are capable”) — a power just *is* the kind of thing that may or may not be expressed. So I don’t think that when you feel the force of the wind, you are feeling something other than the relevant power[s]. If you have direct empirical experience of “a power’s manifestation,” you have direct empirical experience of a power.

    This said (i.e., second), there are probably good reason to reject direct empirical knowledge as the sole criterion for belief re: existence claims about *anything*. I’m reminded that already in A Realist Theory of Science, Bhaskar maintained, as you do, that “to be is just to be able to do.” (RTS p. 182) This led him to distinguish – as anyone might – between a perceptual criterion of existence and a causal one — and to put this distinction to use in arguing for the reality of society (& the properties thereof).

    [We should be clear, though, that the causal criterion of existence will refer to something different for the powers theorist than it will for the Humean. From a powers perspective, “to be real is to be causally powerful,” to use your formulation, means what it says. From a Humean perspective, it can mean only “to be real is to always come first.” (This will be so even if one opts for causation as counterfactual dependence, insofar as the cd just postpones the appeal to regularity.)]

    Ok, so far so good. Fourth, let’s assume (with you and Roy alike) a powers-based Eleatic principle. There is still the question of whether it should or does apply to what you are calling “powers” rather than “manifestations of powers”, and what I would call simply “unexpressed powers.” This is less clear to me. I think I might want to say two things, here. First, I’m not sure that we need it to. Here’s why. On the one hand, an expressed power will (thereby) meet the perceptual criterion for existence (in principle, I mean); this is just to reiterate my first point. On the other hand, in the absence of other inferential evidence, I’m not sure that there would be good reason to think that things of kind x have the power to phi if things of kind x never, ever do phi. Second, I don’t think that it *is* the powers that do the doing! I think it’s the powerful x.

    I find myself wanting to re-think just what work I think the appeal to the causal criterion can do for a powers-based ontology. You might be right that it can get us [knowledge of] the existence of powers in the first place. But even if can’t (or just doesn’t in the exact way that you suggest it might), I think that it does do important work. Thanks again, so much, for provoking this line of reflection.

    What do you & others think?!!

  2. Hi everybody,
    as Stephen points out a realist metaphysician feels unconfortable with a mere empirical ground for knowledge of powers. This, of course, is the reason why a realist is also suspicious that knowledge of a thing only consist in its effect on our senses. What makes the difference in the individuation of a power is the metaphysical argument we offer for its existence and, generally, which epistemological access we secure to that knowledge.

    How do we argue for the supposed advantage of powers over possible worlds? Stephen says that, as theoretical postulates, both share the same boat. I would say that this is true, but they nonetheless row in different directions. I think they strongly differ in their way of representing modality, and I suspect the reason is a different conception of existence-essence relation.

    Lewis modal realism is grounded in his indexical account of actuality, developed through an analysis of Anselm Proof of God’s existence. They both share the realist assumption that “existere” is an act of being. They also share the assumption –unthinkable for an aristotelian– that we can talk about the existence of a thing even if we don’t know its essence. The latter is conceived as beyond human knowledge, thus any epistemological access to it can be secured only by similitude. Conceivability, indeed, is what shapes possible world and what account for the modality of the actual world.

    On the other hand this sense of existence might seems misleading. We can inquiry into a thing’s properties only if we already know what is the thing we are dealing with. Take for instance the famous “hesperus is phosphorus”. The a posteriori necessity of their identity is accessible only because we already know that both are planets, that both are kind of things. Thus, there’s an a priori sense for which essence precede existence. But is this existence the same as the one taken into account by Anselm and Lewis? I’ve reason to believe it is not. For both of them we can know that a thing exists even if we don’t know its essence. Indeed we can say that hesperus and phosphorus exist even if we don’t know what they are. However we might be suspicious that this approach lead us to a real knowledge about what exist.

    Contrary to Aquinas and Anselm, there’s another way to understand existence, which is familiar to Scoto and Avicenna. For both of them existence and essence are two different dimension of being. The latter specify what a thing is, the former is “the way the being is” –the necessary and the possible. Existence is not just the mere act of being that lately might acquire modal status. Cornerstone of Scoto and Avicenna metaphysics is that from knowledge of essence, knowledge about what a thing is, we cannot know if it exist or not, i.e. if it is really realised.

    Thus, when asking “do powers exist? and if they do, how can we know it?” I suspect that what we want to know is not just what exist, but in virtue of what it exist. That is, why a thing has the powers that it has (or, as Ruth might prefer, in virtue of what a thing is capable of its doing. And of course the answer cannot be “because it has such and such powers). And this is possible only if knowledge of existent is able to convey modal knowledge.

    – If we endorse Anselm-Lewis approach we should only say that we know manifestations of powers, not powers in themselves. Thus we only have knowledge of them through patterns of events.

    – If we endorse Avicenna-Scoto approach we might say that we know powers in themselves, but what we can’t know is their complete manifestations because they’re never fully realised (This is how I interpret Stephen’s possible solution to “allow that powers are known and experienced, through their manifestations, but are nevertheless distinct from those manifestations).

    The former approach starts with existence and then comes to essence, the latter starts with essence and then comes to existence. What’s the payoff in taking the second existence/essence approach?

    First, we’re not forced to know powers as something “behind”. They are indeed responsible for the reality of an experience. Similarly, we don’t see the matter, but we have anyway immediate knowledge of material things. Should we then be antirealist about matter? And, of course, to be material is not “the effect” of the matter. Thus we have a reason to be realist about powers which does not relies only on their explanatory roles. What a thing is is its powers to do such and such, and at the same time how the same thing exist is the way in which its powers are realised.

    Second, we avoid to rely on a regularity theory of modality. According to Lewis if we want to know a thing’s essence –what constitute a thing’s nature– we start looking at its counterparts in possible worlds (in the closest neighbourhood). But, as Kripke said, we don’t start with worlds and then look for things, rather we start from things and then we look for what could have happened if things might have been different. However PW modality ground thing’s essence in the reification of the actual existence condition across a modal space –the space inhabited by all the possible worlds. This follow from the fact that the existence of a thing is considered as an act of being, and every beings –included the necessary being– are world bounded. Thus the relation between a thing’s essence and its property –that is, the very possibility of knowing a thing’s modality in respect to a world that it inhabits– is assumed as a brutal fact and represented as a pattern across the modal space. From this perspective is clear how Lewis buy the constant conjunction hypothesis by offering a regularity theory of modality, in which possibilities are mere formal, i.e. mere modal regularities across a space of possibility.

    That’s all we can know about our (actual) world if we rely on PW metaphysics. But Lewis seems to be ok with his perspective. He believe that every worlds is an actuality of a possibility and that we have no reason to regard our own actual world as special except in its relation with us. Indexical account of actuality, indeed, express the simple fact that every actual is a world bounded actual and everytime we say that something is actual we declare our worldboundness in respect to the world in which something which is actual happened to be true. Thus we know that we live in the actual world just because, together with the indexical “now”, “the world in which I exist now is the actual world” is made true and its validity guaranteed by the indexical semantics that ensure that we pick out the right world of utterance. However I suspect that if “is actual” is an indexical we should treat “exist” as indexical as well. This is because I think there’s some PW in respect to which our world is not the actual one, that is, is not the actual world in which I exist. I’ve an argument for that, but Lowe’s one is definitely better than mine (you can find at the end of “Metaphysics as the science of essence”). And more, I don’t want to bother you further.

    (thanks Stephen for the post, thanks Ruth for managing discussions)

    ps: May I suggest to discuss the question of “powers different/not-differetn from manifestations” in another post?

  3. Stephen Mumford wrote, ” Perception occurs through the perceiver being causally affected by the object of perception;”

    Maybe not. Because it is the perceiver (subject) who makes the object. Objects do not come ready made.

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