Tag Archives: Hilary Putnam

Conclusion: Three Arguments against Reference, Part 5

Posted on by under Perception, structural realism

If I’ve accomplished nothing else in this series (previous post here), I hope to have somewhat dispersed the intimidating air that surrounds both Putnam’s model-theoretic argument and the current discussion of Newman’s objection. This air has two sources, I think.

First, both arguments make heavy use of formal model theory. Formal logic, model theory, and especially metatheory are imposing bodies of technical knowledge. They are mathematical. Most philosophers are only minimally acquainted with them. Most graduate programs in philosophy today no longer require students to take metatheory, and even in the old days, the requirement was generally limited to a single course. I would imagine that over ninety-five percent of professional philosophers today could not tell you off the top of their heads what the Löwenheim–Skolem theorems even say. The point is that when people like Hilary Putnam and Michael Friedman start talking about Shoenfield absoluteness and ω-models, nearly all their listeners know they can’t talk to them as equals on that subject.

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Structural Realism and Newman’s Objection: Three Arguments against Reference, Part 4

Posted on by under Perception, structural realism

It’s now time for me to make a small confession, which is that I don’t care very much really about Hilary Putnam’s late-career misadventures with “internalism.” When I first went off to philosophy grad school many long years ago, Reason, Truth, and History was still relatively new and much talked about. I obtained a copy, but I could never get past chapter one. His arguments entailed certain claims that seemed to be just too obviously wrong. They still seem so to me now, and I have emphasized them in previous posts in this series. One is that a brain in a vat would not be able to think about whether it was a brain in a vat, even though the phenomenology of its thoughts would be identical to that of a normal, embodied person thinking (apparently) about being a brain in a vat. That entails that the brain in a vat has no idea what it is thinking about outside its own mind—and by the same token that neither do we. Another is that no natural relation, whether causation or anything else, can determine the referents of our thoughts and percepts, so that—assuming we reject “Platonism”—we have to admit that our thoughts and percepts do not have mind-independent referents. As I say, these claims seemed obviously false, even silly. Neither did it seem like the best use of time to delve deeply into Putnam’s reasoning and try to sort out what was wrong.

On the other hand, I do care about structural realism, which I have come to think is true but which has been bedeviled in recent decades by an argument essentially similar to Putnam’s model-theoretic argument. It has been to better understand and reply to the argument against structural realism that I have at long last performed the examination of Putnam’s model-theoretic argument presented in the previous posts in this series.

In the present post, I explain the argument against structural realism—which by now can be seen in fact to present no great difficulty—and comment briefly on the abysmal state of current discussion of structural realism. (The whole paper on which these posts are based is available here. To return to the third post in the series, click here. To skip to the fifth and final post, click here.)

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The Status of the Model-Theoretic Argument: Three Arguments against Reference, Part 3

Posted on by under Perception, structural realism

The previous post in this series presented Hilary Putnam’s “model-theoretic argument” to the effect that no representational system whatsoever, including natural language and mental states such as thoughts and percepts, can refer to anything definite unless the assignment is made externally by an agent outside the representational system or “Platonically” by means of some non-natural access to the domain of reference. For example, the little airplane icons on an air traffic controller’s screen can be assigned to specific planes because one can see both the icons and the planes—sometimes just by looking out of the control tower window—to map the icons to the planes. But when it comes to thought and perception, we have no such independent access to the intended referents. How in that case is any determinate mapping possible? Putnam’s claim, which the model-theoretic argument is intended to establish, is that, barring some “Platonic” cognitive channel to external reality that cannot be explained by natural science, no determinate mapping is possible. Therefore, our thoughts and percepts have no truth conditions that depend on the mind-independent world being any one way rather than any other. This is what Putnam calls “internal realism.”

In the present post, we critically examine the model-theoretic argument. (The whole paper on which these posts are based is available here. To advance to the next post in the series, click here.)

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Hilary Putnam’s Model-Theoretic Argument for “Internal Realism”: Three Arguments against Reference, Part 2

Posted on by under Perception, structural realism

The first post in this series examined Hilary Putnam’s famous argument that a “brain in a vat” (BIV) could not know that it was a BIV—or even think or wonder whether it was a BIV—because its words and thoughts would lack the causal-perceptual links to vats and brains in its environment needed for them to refer to those objects. However, as I said in that first post, for Putnam the BIV argument was just a warm-up exercise. He uses the traditional BIV scenario to illustrate what he regards as the key error of “metaphysical realism” (the view that our percepts and thoughts refer to mind-independent things): that it necessarily relies on a God’s Eye perspective from which we can determine what mind-independent things our percepts and thoughts refer to. Of course, there is no God’s Eye perspective available to human beings, and that is why the project of metaphysical realism must end in failure. Thus, Putnam’s real view is that even if the BIV had the same causal-perceptual embedding in its environment that we enjoy, it would make no difference! Its percepts and thoughts would still not refer to mind-independent things. Reference to mind-independent things is impossible in general. The traditional worry about whether you could be a BIV is a useful entrée to these issues because it presupposes metaphysical realism. Only a metaphysical realist would or could worry about being a BIV, because only if the objects of thought were mind-independent would it be possible to be so radically in error about the nature of one’s environment.

Why does Putnam think that only a God’s Eye perspective can determine the reference of our thoughts and percepts? The reason is given in the so-called “model-theoretic argument” that Putnam presents in each of the three works I mentioned in the first post (“Realism and Reason” [R&R], “Models and Reality” [M&R], and Reason, Truth, and History [RT&H]. In the present post, I explain the argument and the “internal realist” view that Putnam advocates on the basis of it. In the next post, we will examine the merits of the model-theoretic argument. (The whole paper on which these posts are based is available here. To skip to the third post in the series, click here.)

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Could Hilary Putnam Have Been a Brain in a Vat?: Three Arguments against Reference, Part 1

Posted on by under Perception, structural realism

In previous posts (such as this one and this one), I have sometimes alluded to the philosophy of structural realism. Structural realism says that we are unable to know the intrinsic character of the world outside our minds, although we are able to know a great deal about the structure of that world, especially its causally relevant features. Thus, we can know what we need to know to survive and thrive in our environment, we just can’t know what it is like intrinsically. For instance, we cannot know whether the surfaces of objects have the colors they appear to have in our visual perceptions of them or the hot and cold qualities we feel them to have, etc. Even the intrinsic character of spatial relations may not be as it appears to us. Still, the structure and dynamics of all these things is accessible to us—which is fortunate, because that is what matters for successful action.

I think structural realism is true and indeed inescapable. However, discussion of it in philosophy today is blighted by obsession with something called “Newman’s Objection,” after Max Newman, a Cambridge mathematician who published an important critique of Bertrand Russell’s version of structural realism as advanced in Russell’s book, The Analysis of Matter (1927). In my view, Newman rightly identified an important flaw in Russell’s structural realism, but not in structural realism per se, which has many options available for removing the difficulty. Unfortunately, many philosophers today, including many structural realists, treat Newman’s Objection against Russell (and subsequent formulations essentially like Russell’s), unless it can be refuted somehow, as a decisive refutation of structural realism itself. The result has been a lamentable lack of progress in developing the implications and insights of structural realism.

In what follows, I will explain how I think Newman’s Objection should best be handled and why it is a paper tiger. However, I have chosen to do so via an analysis of a much more well-known argument that in its essentials is practically identical with Newman’s, namely Hilary Putnam’s “model-theoretic argument” against the possibility that the terms of natural language or of our thoughts and percepts can have determinate referents in the mind-independent world.

This means that “what follows” is going to be a long haul! If anyone wants to read the whole paper in one fell swoop, it can be found here. Here at PoT, I will send it out in five installments, of which this post is the first. In this first installment, I begin with Putnam’s own warm-up exercise: his argument that a “brain in a vat” would be unable even to think that it was a brain in a vat. (To skip to the second installment, click here.)

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Roderick Long (and others) on Hilary Putnam

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Here’s a nice brief memorial to Hilary Putnam by Roderick Long, with a bonus link to Roderick’s review of Putnam’s Collapse of the Fact/Value Dichotomy and Other Essays, from Reason Papers 28 (2006). Roderick has a real gift for writing these RIP notices, emphasizing the deceased’s achievements but not ignoring what might legitimately be criticized.

Here’s Martha Nussbaum in The Huffington Post.

Jane O’Grady in London’s Guardian.

The official notice from Harvard, with a link that goes to Putnam’s blog, Sardonic Comment.

Though it’s not online, I’ve always found the interview of Putnam in Giovanna Borradori’s The American Philosopher candid and interesting.

Feel free to add any particularly good ones in the combox.