Thomas Nagel’s view that Davidson is an idealist

In the sixth chapter of The View from Nowhere, Thomas Nagel claims to have uncovered a widespread form of idealism. A simple attempt to formulate the view that Nagel regards as idealist is as follows:

(CT) Necessarily, if X exists, then it is possible that someone exists who counts as one of us and conceives that X exists.

(CT) is short for conceivability thesis. To count as one of us, Nagel suggests, is to have mental capacities that are not significantly superior or inferior to his own. This definition involves some vagueness, but the vagueness will not matter below. Note that the simple formulation of the conceivability thesis might need some revision to perfectly capture the thesis that Nagel has in mind. The points below should still apply after any needed revisions.

Nagel identifies Donald Davidson as an idealist. However, Davidson does not say that he is committed to (CT). Nagel treats him as committed to it, because Davidson endorses the following thesis:

(DT) Necessarily, if S is a true sentence in another language, S can be translated into our language.

But does (DT) bring with it a commitment to (CT)?

In ‘Nagel on Conceivability’, I offer an example to deny this. Imagine that a child can understand how to play chess and can understand a justification for the claim that, within a particular game, checkmate can be achieved in two moves. But they cannot understand justifications for the claim that checkmate can be achieved in four moves. These justifications are too long for them to follow. Nevertheless, the justifications can be articulated using individual words that the child knows. The same vocabulary that is used to talk about chess in general, including justifying checkmate in two moves, can be used to articulate these justifications. But the child cannot follow them. Thus there is a gap between which truths the child can conceive and which truths can be articulated in their language. Similarly, there might be a gap between which truths we can conceive and which truths can be articulated in our language. There may be truths which can be articulated using words that we know yet which we cannot conceive, owing to our cognitive limitations.

(CT) is not itself about what is true, rather about what exists. But from the example, it seems that one can coherently endorse (DT) yet deny (CT). There might be features of the world that we cannot conceive. Davidson can allow that these features exist and that all truths about them can be formulated in our language. Nevertheless, our cognitive faculties do not enable us to understand these truths.

References

Edward, T.R. 2009. Nagel on Conceivability. Abstracta 5: 16-29.

Nagel, T. 1986. The View from Nowhere. New York: Oxford University Press.

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