Abstract
In ‘Ramseyan Humility’ David Lewis argues that a particular view about fundamental properties, quidditism, leads to the position that we are irredeemably ignorant of the identities of fundamental properties. We are ignorant of the identities of fundamental properties since we can never know which properties play which causal roles, and we have no other way of identifying fundamental properties other than by the causal roles they play. It has been suggested in the philosophical literature that Lewis’ argument for Humility is merely an instance of traditional scepticism, to which traditional responses to scepticism are applicable. I agree that in ‘Ramseyan Humility’ Lewis does present an argument to which it is appropriate to consider the applicability of responses to traditional scepticism—he argues that we irredeemably lack the evidence to rule out possibilities in which different properties occupy the causal roles described by our best physical theory. And prima facie this is just the kind of argument responses to traditional scepticism are designed to tackle. However, I will argue that Lewis bolsters this argument with a second. This second argument serves to deepen Lewis’ case and cannot be met with a response to traditional scepticism. For Lewis argues that not only do we lack evidence for which properties play which roles, we lack the ability to grasp any such proposition about role-occupancy. And if we cannot grasp any such proposition we cannot know it.
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Notes
Lewis also extends this conclusion to non-fundamental properties. I will not be considering the possible extension of the argument here.
That is, the theoretical terms are ‘implicitly defined’. For more on the notion of implicit definition see Lewis (1970).
So satisfied by a different ordered n-tuple of properties than satisfies it at the actual world.
Exactly what permutations quidditism ought to allow is not a straightforward matter. See Hawthorne (2006) for discussion.
And that these are the only such beliefs we can have is the assumption if premise (2) of HA.
On two dimensional semantics, it is the secondary intension that is in question here. Quite a bit more on this in Sect. 3.
And, if we assume the only way we can represent the facts about role occupancy are of this form, I could not be brought to doubt the proposition at all (that is, the qualification that I could not be brought to doubt that this sentence expresses a true proposition, is superfluous).
Again, assuming, as we are, the truth of T.
If we consider Lewis’ position in ‘Elusive Knowledge’, the impression is that Lewis holds that there is not a deep or epistemologically interesting difference between the two kinds of cases mentioned above—‘external-world’ and sceptical hypotheses on one hand and competing but equally empirically adequate theories on the other. In both cases, a subject only knows some proposition if their evidence excludes all possibilities in which the proposition is false, and where ‘all’ quantifies over a contextually restricted domain of possibilities.
Adding a little context: The imparting of power to identify fundamental properties by acquaintance that Lewis speaks of is not merely a matter of permitting acquaintance. As Lewis explains just before this quote, on his view, acquaintance itself would be insufficient for identification. Crudely, this is because, on Lewis’ view, the subjective state of the acquainted subject could have obtained even if a different property was playing the role of the property with which the subject was acquainted. See Lewis (1996) for a relevant discussion regarding qualia.
For Jackson these are the A and C intension, respectively. See, for instance, Jackson (2000, Chap. 3).
Indeed this part of the restriction on what representation of facts are allowed in the description of an arbitrary world that is employed by Chalmers (2002) when discussing grasp of the primary intensions. Chalmers picture is, roughly, that the grasp of primary intension of an expression consists in the ability to determine the extension of that expression at any world given sufficient information about that world—with the proviso that the description of the world cannot include terms whose primary and secondary intensions diverge.
This is not to say that quiddistic facts aren’t among the facts to be known about the counterfactual world, indeed they must be according to quidditism. The problem is that we have no way of representing these facts which will allow them to help in assessing the truth of the proposition in question. The only way we have of representing these facts is by indexical reference to the actual world, and the two dimensional restriction rules this way of representing them out from the information given to a subject about a counterfactual world.
Putting aside here the possibility that this isn’t a genuine possibility on the most plausible version of quidditism. QT only requires that every property has some pp world in which it plays another role and that there is some pp world where its role is occupied by another property. For consideration on what kind of permutations would be permissible see Hawthorne (2006).
What they do grasp, the primary proposition, is that, say, the watery stuff covers most of the earth. I think it is right to describe the situation as one on which they don’t grasp propositions about water since what they believe would be true if it was XYZ that covered most of the earth.
Where haecceitism is the parallel thesis to quidditism for particulars. That is, the identity of a particular is independent of any ‘qualitative’ features. See Chisholm (1967) for a classic discussion.
Locke (2009) takes up Langton on this point arguing that the pp worlds could never be properly ignored.
One way in which the application of grasp contextualism might be supported is by taking grasp to be knowledge of meaning, or knowledge of which proposition has been expressed. In this way, knowing which proposition has been expressed by some utterance is just another case of knowing P. However, if ‘knowledge of meaning’ is the kind of thing that can be secured by contextualist means alone, then the kind of worry just raised for one understanding of Lewis’ contextualism arises. This is the worry that evidence plus context alone is insufficient for a complete account of what it is for a subject to know something. Part of what strikes me as missing is an account of understanding or grasp. Connectedly, an account of grasp as knowledge of meaning seems potentially in danger of regress: Say grasp of an utterance of S is knowledge that S expresses P. And to know that S expresses P the subject must grasp ‘S expresses P’ and so they must know something of the form ‘‘S expresses P’ expresses P*’, and to know that ‘‘S expresses P’ expresses P*’, they must know…, etc.
References
Bird, A. (2007). Nature’s metaphysics. Oxford: Oxford University Press.
Chalmers, D. (2002). On sense and intension. Philosophical Perspectives, 16, 135–182.
Chisholm, R. (1967). Identity through possible worlds: Some questions. Nous, 1(1), 1–8.
Hawthorne, J. (2006). Quantity in Lewisian metaphysics. In J. Hawthorne (Ed.), Metaphysical essays. Oxford: Oxford University Press.
Jackson, F. (2000). From metaphysics to ethics: A defence of conceptual analysis. New York: Oxford University Press.
Langton, R. (2004). Elusive knowledge of things in themselves. Australasian Journal of Philosophy, 82(1), 129–136.
Lewis, D. (1970). How to define theoretical terms. The Journal of Philosophy, 62(13), 427–446.
Lewis, D. (1996). Elusive knowledge. Australasian Journal of Philosophy, 74(4), 549–567.
Lewis, D. (2009). Ramseyan Humility. In D. Braddon-Mitchell & R. Nold (Eds.), Conceptual analysis and philosophical naturalism. Cambridge, MA: MIT Press.
Locke, D. (2009). A partial defense of Ramseyan Humility. In D. Braddon-Mitchell & R. Nold (Eds.), Conceptual analysis and philosophical naturalism. Cambridge, MA: MIT Press.
Ney, A. (2007). Physicalism and out knowledge of intrinsic properties. Australasian Journal of Philosophy, 85(1), 41–60.
Schaffer, J. (2005). Quiddistic knowledge. Philosophical Studies, 123, 1–32.
Whittle, A. (2006). On an argument for humility. Philosophical Studies, 130(3), 461–497.
Acknowledgments
I am very grateful to Bill Brewer and Guy Longworth for very helpful discussions and for comments on earlier drafts of this paper. Thanks to an anonymous referee for pressing this point, and for other helpful comments and challenges throughout.
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Kelly, A. Ramseyan Humility, scepticism and grasp. Philos Stud 164, 705–726 (2013). https://doi.org/10.1007/s11098-012-9871-1
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DOI: https://doi.org/10.1007/s11098-012-9871-1