Moore, of course, thought that intrinsic value is the central evaluative property. Admittedly, specifying what counts as an intrinsic property is an interesting and difficult question in itself. Let me offer just a quick sketch. On this proposal, whether an object has an intrinsic property cannot be affected by anything outside the object. This entails that all possible duplicates of an object have all the same intrinsic properties as the object but they can differ in all their other properties that are thus extrinsic. Metaphysically speaking, Moore then thought that the intrinsic property of intrinsic value is a ‘non-natural’ property. Again, it is an interesting and difficult question what this actually means – what the difference between non-natural and natural properties is exactly supposed to amount to. As this doesn’t matter below, I’ll be neutral about this here.
One classic objection to non-naturalism about intrinsic value is an epistemic challenge. As John Mackie put it, ‘[c]orrespondingly, if we were aware of them, it would have to be by some special faculty of moral perception or intuition, utterly different from our ordinary ways of knowing everything else.’ So, traditionally, it has been thought that it is the non-naturalist aspect of Moore’s view that creates the epistemic problems. I want to suggest that this is false because the problem really is in the intrinsic aspect of Moore's properties. David Lewis, in his 2002 Gareth Evans Memorial lecture ‘Ramseyan Humility’, offers a strong argument to the conclusion that all intrinsic properties are unknowable – whether they be non-natural or natural properties (I wish I had read this earlier… most people probably know this well). If this is right (and I think it is), then naturalists about intrinsic value face the very same epistemic problems as the non-naturalists about intrinsic value.
Here’s a quick attempt to explain Lewis’ argument (much influenced by Rae Langton’s admirably clear discussion and also by Dustin Locke’s presentation – also sorry if I get this wrong). Let’s start from the idea that science can help us investigate the ‘nomological structure’ of the world. This is to say that science informs us about the roles which different properties of objects play. It’s part of the role of ‘mass’ that it curves the space-time and makes objects resist forces in acceleration. So, science can tell us that there is a property which has a certain extrinsic role. However, this does not yet give us information about the intrinsic nature of the property that plays this external role. The question then is, could we also know what the intrinsic properties of the objects are like – the properties that realize the roles described in science? Here’s Lewis’ argument to the ‘no’ conclusion.
Lewis starts by imagining a situation in which we have a true and complete, ‘final’ theory of the world. Amongst other things, this theory T describes the roles of all the fundamental properties of the world that determine how the world works. These properties are the intrinsic properties of the objects of the actual world on which all other intrinsic properties supervene. Furthermore, T does not mention any ‘idlers’ – instantiated fundamental properties that have no consequences or any ‘aliens’ – other uninstantiated and merely possible fundamental properties.
Theory T defines its theoretical terms in terms of the causal roles played by the properties for which these terms stand. Some of the terms of this theory thus come to stand for the fundamental properties of our world. Those properties are then the unique actual realization of T. Of course, in addition to T’s language, we also have our own natural language which Lewis calls the ‘old language’ or o-language. We can describe all our observations completely in the o-language.
T is, in effect, a long conjunction of sentences (presumably including laws and state-descriptions). It can thus be ‘Ramseyfied’. In this process, we replace all the names of the fundamental properties in the theory by existentially quantified variables. So, we get, “For some x1, …, for some xn T (x1, …, x2)”. This Ramsey sentence says that there is at least one actual realization of T. Given that T was the correct theory of the world and we got the Ramsey sentence from T by substituting names with existentially qualified variables, just like T, the Ramsey sentence entails all the observation sentences of the old language that were derivable from T. Therefore, the predictive success of the Ramsey sentence in question is exactly the same as T’s. This means that, as Lewis puts it, ‘there is no way to gain evidence for T that is not equally evidence for the Ramsey sentence.’
We then get to the crucial stage of the argument. Assume that in the actual world, there is a set of fundamental intrinsic properties <P1, …, P2> that realize the Ramsey sentence of T. Lewis calls this the actual realization of T. Assume also that there is another possible world in which another set of fundamental intrinsic properties <Q1, …, Qn> realizes the Ramsey sentence of T. This set is a possible realization of T. The point of Lewis’ argument is that, if there are many possible realizations of T (including the actual one), then no possible observation could ever tell us which one of the possible realizations of T is the actual one. Why? This is because whichever realization of T is true, the Ramsey sentence is still true and, as we saw, that Ramsey sentence itself already entails all our observations described in the o-language. So, no possible observation can get us beyond the Ramsey sentence which still leaves the question of the realizer properties open.
The last part of Lewis’ argument is to show that there must be multiple realizations of T. Lewis offers two arguments to this conclusion. The permutation argument claims that we could permute two fundamental basic properties and the laws that govern them whilst leaving everything else fixed. We would then get a different realization of T and it is impossible to rule this realization out as the actual one on the basis of what we observe. The second argument claims that we could replace any actual fundamental property with an idler or an alien. If we made the matching changes to the laws that govern these properties, we would again have another realization of T that would be indistinguishable to us observationally.
To summarise, if Lewis’ argument works, then we can never know which intrinsic properties objects have – be they natural or nonnatural properties. Lewis’ argument is about fundamental properties of the basic properties, but as he shows, given supervenience, this argument can be extended to other intrinsic properties of more complex objects. If this is right, then naturalism itself does not solve the epistemic problems of intrinsic value. Now, of course, there are ways to resist Lewis’ argument. You could claim that it relies on a mistaken infallibilist notion of knowledge or that there are some non-scientific ways to know the intrinsic properties. My hunch, however, is that all these ways to save the knowledge of intrinsic natural properties will also work for the non-naturalist properties. Or, we might think that this argument leads to structuralist or dispositional views of properties. But, this would be bad news for intrinsic value generally.
Jussi, are you convinced that intrinsic value is an intrinsic property?
Moore himself didn’t think so:
(From “The Conception of Intrinsic Value”; I added the boldface.)
This is interesting Jussi, but a worry: Lewis’ argument is interesting, but I can’t believe it’s what lies behind *all* epistemic objections to non-naturalism (speaking of “the” epistemic challenge seems misleading to me). Could you explain, for instance, how it would map onto Mackie’s worry about what the relevant faculty of mind is that is capable of perceiving these non-natural features of the world? These look like two independent issues.
Hi and thanks all
Jamie – well I’m inclined to think that intrinsic value is an intrinsic property. Thanks for reminding of that Moore paper – I had forgotten all about it. Two things to say about this. After that passage, Moore says that he doesn’t really know why intrinsic value is not an intrinsic property despite the fact that (1) holds. This makes his account of intrinsic properties mysterious. On many other criteria, like the duplicate one, intrinsic value comes out as an intrinsic property.
However, and more importantly, I think the thought goes through even if we grant Moore both (1) and (2). So, assume that, intrinsic value is determined by the intrinsic nature of the object and that intrinsic value is not an intrinsic property. Let’s also assume that intrinsic value is a natural non-intrinsic value which is determined by the objects natural intrinsic properties. If Lewis is right that the intrinsic natural properties of the object are unknowable, then the non-intrinsic property of intrinsic value would still be unknowable even if it were a natural property.
Alex,
well, I’m starting to think that this Lewis argument does go deeper and behind what is worrying many about the idea of intrinsic value. So, take Mackie’s worry about a moral radar that would be needed to perceive the intrinsic value. What seems to motivate this kind of worry is a certain kind of a causal account of knowledge. On this view, knowing something requires a causal connection to the fact known and perception is supposed to provide that kind of a connection – after all, it is the causal mechanism through which we come to know. But, if we take the Lewisian line seriously, then whatever we come to know by perception and the causal mechanism it involves in our best form of inquiry of science is never the intrinsic properties of the objects. What we come to know are the causal roles which those properties play. So, if we take the view of knowledge that motivates Mackie’s worry into account, then that worry does threaten not only non-natural properties but rather more broadly all intrinsic properties.
Jussi,
Hm, properties determined by unknowable properties are themselves unknowable?
That can’t be generally true; maybe it’s true for certain kinds of determination. But you need more premises.
Good point. I have to think of how to provide the further premises. This is probably saying the same thing in different words… I’m assuming that in (1) Moore is talking about the good-making properties and we can understand good-making along the lines it is usually understood (I like Zangwill on this). The further premise I need is something like you cannot know that an object has intrinsic value without knowing at least some of the properties that make the object good. But, if the Lewis argument works, we cannot know anything about the good-making properties in so far as these are intrinsic properties. I do admit that there are some gaps here but this bit starts to seem plausible to me.
Hi Jussi,
Thanks for this thoughtful post on no less than two of my favorite subjects (Ramseyan Humility and normative skepticism)!
While I would like to think that Lewis’ argument has the kind of significance you say it has, I think I have to side with Alex in thinking that it cannot really be what lies behind the standard epistemic objections to non-naturalism. Here’s why: there are possible ways of responding to Lewis’ argument in the case of natural properties that would simply be non-starters in the case of non-natural properties. In my paper on Ramseyan Humility, I discuss, for example, the direct realist response to Lewis’ argument. According to this response, the proposition that *this brick has mass* (where ‘mass’ rigidly refers to the property that actually realizes the mass role) can be part of one’s evidence, and thus one’s evidence will rule out possible worlds in which this brick has some other property that, in those worlds, realizes the mass role. The direct realist will say that that this proposition can be part of my evidence because I can directly perceive that this brick has mass, and (here’s the important part) I can directly perceive that this brick has mass because I am *causally connected* to this brick’s mass in the right kind of way. This sort of response won’t help a normative non-naturalist, because (allegedly) we don’t enter into causal relations with non-normative properties. Hence, there is a potential way to refute Lewis’ argument in the case of natural properties that (allegedly) won’t work in the case of non-natural properties. That means that there is (allegedly) something particularly troublesome about *non-natural* properties.
Hi Dustin
thanks for your comment and also I have really enjoyed your work on the topic. It’s all been quite revalatory for me. Few quick comments on your response though.
Firstly, it seems to be that your response supports the idea that the Lewisian worries about intrinsic worries are behind many of the objections to intrinsic values. We seem to agree that Lewis creates a challenge for anyone who wants to be a realist about intrinsic properties. Whether it is your scientific theory or evaluative theory, you need to explain just how is it that we can know about such properties given that our evidence seems unable to decide between different realizations of the Ramsey-sentence.
Now, as I read you, turns out that direct realism+naturalism has an answer to this question which is not available for the non-naturalists about intrinsic value. If this were true, then it would be true that there is something particularly troublesome about non-natural properties, but we can understand what this troubling element of them is only if understand the challenge which Lewis’ argument presents us with. This means that the problem of the intrinsic properties is still within the scope of Lewis’ argument. I take it that Alex wanted to say that the epistemic problems of such views lie completely outside the realm of the Lewis argument.
For what it is worth, I also think that a modified version of this response is available for the non-naturalist. It take it that the crux of this response is that the external intrinsic properties can be a part of the content of the evidential states. This much the non-naturalist can agree on.
The second step is to argue that the intrinsic properties can be a part of the content of the evidential states because of a causal connection. This is to adopt a causalist view about the metasemantics of the evidential states.
I’ve been reading Sider’s new book recently and I’m fairly convinced by his views that causation cannot function as the required kind of semantic glue here even in the case of many scientific terms such as mass. If this is right more generally, then the non-naturalist too can claim that the intrinsic evaluative properties to can function as proper joints in nature that function as semantic magnets.
So, it’s not clear to me that the non-naturalist too could not be an externalist about the content of the evidential states and thus rule out the alternative worlds with different intrinsic properties.
You are certainly right that, in so far as Lewis’ argument applies to *all* intrinsic properties, it applies to intrinsic value as well (assuming that intrinsic value is an intrinsic property). But I thought you were claiming something stronger than this–namely, that “THE problem really is in the intrinsic aspect of Moore’s properties” (emphasis added). I don’t think that can be, because there is a certain (alleged) problem for non-natural intrinsic properties that specifically concerns there being non-natural, not their being intrinsic.
However, it is interesting that (as you point out) there are possible refutations of Lewis’ argument that will carry with them a refutation of the (alleged) traditional problem for non-natural properties. Maybe you could describe your project like this: (1) many people think that there is a problem for intrinsic non-natural properties but (2) all intrinsic properties face a similar problem and (3) the best solution to the latter problem carries with it a solution to the former. I for one definitely want to read that paper when it comes out!