Of Brains in Vats,Whatever Brains in Vats May Be

Hilary Putnam has offered two arguments to show that we cannotbe brains in a vat, and one to show that our cognitive situationcannot be fully analogous to that of brains in a vat. The latterand one of the former are irreparably flawed by misapplicationsof, or mistaken inferences from, his semantic externalism; thethird yields only a simple logical truth. The metaphysical realismthat is Putnams ultimate target is perfectly consistent withsemantic externalism.     

Johnsen on Brains in Vats

This is a response to a recent Philosophical Studies article by Bredo Johnsen, in which he makes a number of criticisms of Putnamian anti-skeptical arguments.     

Sensitivity,Safety, and Brains in Vats

Both sensitivity and safety theorists concur that their accounts should be relativized to the same method that one employs in the actual world. However, properly individuating methods has proven to be a tricky matter. In this regard, Nozick (Philosophical Explanations, Harvard University Press, Cambridge, 1981) proposes a Same-Experience-Same-Method Principle: if the experiences associated with two method tokens are the same, they are of the same type of method. This principle, however, has been widely rejected by recent safety and sensitivity theorists. In this paper, I raise an argument in favor of Nozick: not endorsing the principle leads to some rather implausible consequences when certain skeptical scenarios are considered—i.e., scenarios in which skeptical possibilities are ‘close’. Additionally, this argument reveals some important lessons about skepticism in general and the place of modal accounts of knowledge in the internalism/externalism debate.

     

Putnam,Searle, and externalism

Summary To sum up, then, both kinds of Putnam's arguments established externalism, though they suffer from several defects. Yet, I think Searle's discussion of these arguments contributes to our understanding of what makes externalism true, and forces us to accept a moderate version of externalism. Searle's own account of the TE story shows us, within a solipsistic outline, how two identical mental states can be directed towards different objects, and further, that the content-determination of indexical thoughts does not necessarily involve external factors. We are thus led to search elsewhere (i.e., not in the nature of indexical thoughts nor in the mere fact of there being identical thoughts with different intentionalities) for what makes the thoughts in question external. Searle formulates the thesis that intension determines extension as asserting that intension sets certain conditions that anything has to meet in order to fall under its extension. I showed that this is a trivial and implausible understanding of that thesis. Yet, it leads us to distinguish between an intension's setting conditions for falling under its extension and its fully determining such conditions, and thus to see in what sense externalism is true: in the sense that there are intensions that do not fully determine the conditions for falling under their extensions. Rather, they leave indeterminacies. This version of externalism is a moderate one, since though the intensions do not fully determine extensions, they, so to speak, determine their indeterminacies, by specifying the possible external facts that can complete the determination of extension. (The intensions, as I said, function like open sentences, and can be viewed as narrow contents.) So what's in the head plays a much more important role in determining content than Putnam takes it to play. Searle's pointing out that Hilary's concepts elm and beech are different also contributes to seeing this phenomenon: we realize that in that case the difference between the concepts is what is responsible for the fact that the completions of the extension-determinations are different. I think that this way of viewing the facts shows that the externalist turn is not a great revolution, and that with the help of the concept of narrow content we can accept it without abandoning the traditional views about the mind as the source of content, and without being embarrassed by the very idea of (realistic) belief-desire psychology.     

Putnam,realism and truth

There are several distinct components of the realist anti-realist debate. Since each side in the debate has its disadvantages, it is tempting to try to combine realist theses with anti-realist theses in order to obtain a better, more moderate position. Putnam attempts to hold a realist concept of truth, yet he rejects realist metaphysics and realist semantics. He calls this view internal realism. Truth is realist on this picture for it is objective, rather than merely intersubjective, and eternal. Putnam introduces a concept of epistemic idealization — epistemically ideal conditions, or idealized justification — to try to ground the strong objectivity of truth without sliding into metaphysical realism. I argue that the concept of ideal conditions to which Putnam appeals does not cohere with his (anti-realist) commitment to an assertability conditions account of meaning.     

More on Putnam and Tarski

Hilary Putnam's famous arguments criticizing Tarski's theory oftruth are evaluated. It is argued that they do not succeed to undermine Tarski's approach. One of the arguments is based on the problematic idea of a false instance of T-schema. The otherignores various issues essential for Tarski's setting such as language-relativity of truth definition.     

Putnam and Constructibility

I discuss and try to evaluate the argument about constructible sets made by Putnam in ‘ ”Models and Reality”, and some of the counterarguments directed against it in the literature. I shall conclude that Putnam’s argument, while correct in substance, nevertheless has no direct bearing on the philosophical question of unintended models of set theory.