In a recent issue of the New York Review of Books the eminent physicist Freeman Dyson delivered the following assessment of contemporary philosophers: “they are a sorry bunch of dwarfs. They are thinking deep thoughts and giving scholarly lectures to academic audiences, but hardly anybody in the world outside is listening. They are historically insignificant.”
The Harvard philosopher Hilary Putnam might seem a dwarf at first glance, and his latest collection of essays, Philosophy in the Age of Science, another scholarly text for academics. It is a weighty book from a university press with foreboding chapter titles like “Axioms of Set Existence.” It will likely be ignored by non-philosophers. This is a shame because Putnam, in lucid and readable prose, confronts some of the most philosophically rich debates out there. Can science produce an exhaustive description of the universe? Are moral values subject to rational scrutiny? Can we give an account of mind that is compatible with what we know about cognitive psychology?
Putnam, unlike most philosophers, does not take a slow and plodding approach. His style is more detached, more panoramic. He takes long strides, condensing arguments into a few sentences, rather than the whole chapters one would usually expect. What Putnam’s approach lacks in microscopic nuance, it makes up for with its ability to capture the big picture—to see how small philosophical problems relate to grand, overarching topics.
This kind of approach can come off as naïve or arrogant, unless deftly handled. Bertrand Russell got away with it in his Problems of Philosophy because he was a famously brilliant logician, who also spent decades thinking about the arguments he reduces to short paragraphs. For similar reasons William James’s Pragmatism, a poignant American counterpoint to Russell, gets away with its grandiose and sweeping style. Putnam pulls off the trick too—he is one of the few living philosophers in the same mould as Russell and James.
Like Russell, Putnam began his philosophical career working on topics concerning logic and mathematics. In the 1960s his work with three other mathematicians led to the solution of Hilbert’s Tenth Problem, and his work with Martin Davis led to the creation of an algorithm about satisfiability for first-order predicate logic. Like William James, Putnam has a keen eye for where lofty philosophical notions such as truth, knowledge, value, and justification can be related to pragmatic concerns about use and practicality. And like James and Russell, Putnam sees both science and philosophy as participating in a similar project of refining our conception of reality. Sadly Putnam has never enjoyed a similar level of fame or public influence, though his famous essay “Brain in a Vat” may have been one of the inspirations behind The Matrix, a film which introduced philosophical scepticism to a whole new audience.
Within the world of academic philosophy, Putnam is famous (perhaps notorious is the word) for his habit of changing his mind. His entry in the joke Philosophical Lexicon runs:
“Hilary: A very brief but significant period in the intellectual career of a distinguished philosopher. “Oh, that’s what I thought three or four hilaries ago.”
His longtime admirer Sidney Morgenbesser once quipped of Putman: “He’s a quantum philosopher. I can’t understand him and his position at the same time.”
This intellectual mutability extends to his politics and personal life. Born in 1926 to an intellectually gifted, middle-class Jewish family in Chicago, Putnam was raised an atheist and progressive. In the 1960s Putman was a vocal defender of the Civil Rights Movement, a critic of the American involvement in Vietnam, and a member of the communist Progressive Labor Party. By 1976 Putnam, after grappling with the human rights abuses by communists, left the PLP and gave up his support for Maoism. Both Putnam and his wife, the philosopher Ruth-Anna Putnam, returned to Judaism after decades of atheism. Putnam was 68 when he had his Bar Mitzvah.
Changing your mind in any situation, much less academic philosophy, is seen as a sort of weakness. It takes a very secure ego to end a debate with “well I think I may have been wrong.” Putnam’s shifts in position demonstrate not just his intellectual confidence, but also the virtue of seeing the bigger picture. Putnam is able to step back for a moment and see a particular position, say functionalism in philosophy of mind, and notice that it doesn’t quite fit in with a greater commitment in metaphysics and philosophy of language.
In Philosophy in an Age of Science Putnam wants us to take a step back and consider the relationship between two deeply entrenched ways of understanding the world. One, the scientific position, attempts to explain things in mind-independent and law-like terms. This is often called the descriptive or “is” position. The other, the moral position, attempts to explain things in mind-dependent and value-laced terms. This is often called the normative or “ought” position.
For the past century philosophers, and our culture in general, have seen these positions as mutually exclusive. This line of thought was taken up during the 1940s and 50s by the logical positivists. Wanting to place all thought on firm scientific ground, they proposed a severe reduction of the scope of philosophy. Proper philosophy, they argued, should concern itself with the analysis of well-defined propositions with clearly identified conditions for verification.
Inevitably, after the reign of the logical positivists, there followed a backlash. Their sharp division between the scientific and normative positions began to appear untenable. Putnam was one of the leaders of the attack, consciously rejecting the primacy of the scientific stance that has dominated philosophy since Russell.
Philosophy in an Age of Science condenses a career’s worth of work but it is Putnam’s criticism of the false distinction between facts and values that is his most convincing and important argument. Briefly put, in Putnam’s view there is no clear-cut way to distinguish facts from evaluative judgements.
This goes against one of the most widely held convictions of the modern age. It seems a simple matter to sort our beliefs into neat piles—objective facts in one corner, subjective opinions and values in another. “The acceleration of gravity on earth is 9.8 metres per second squared” as opposed to “Schubert’s music is better than Justin Bieber’s.” Politicians and pundits are always trying to “get to the facts.” We placate disagreements with “well that’s just my opinion.” Working in the background here is another idea: that facts are something that all rational people can agree upon while values are ultimately impervious to reason and argument. This view of the world as divided into the subjective and objective is so deeply held that many people assume that it is just the way things are and not a philosophical position.
Putnam’s argument against this dichotomy is not any sort of naive relativism, where there simply is no difference between asserting “2+2 =4” and “That pasta carbonara tasted revolting.” Putnam’s point is simply that values and facts are inextricably entangled.
Take scientific judgements—the embodiment of a discourse which is supposedly factual and objective. Imagine two scientists are proposing competing theories about the motion of the moon. One scientist argues that the moon orbits the earth at such and such a speed due to the effects of gravity and other Newtonian forces. The other, agreeing to the exact same observations, argues that behind Newtonian forces there are actually undetectable space-aliens who are using sophisticated tractor beams to move every object in the universe. No amount of observation will resolve this conflict. They agree on every observation and measurement. One just has a more baroque theory than the other. Reasonably, most of us think the simpler theory is better.
But when we ask why this theory is better, we find ourselves resorting to things that are patently non-factual. We may argue that theories which postulate useless entities are worse than simpler ones—citing the value of simplicity. We may argue that the space-alien theory contradicts too many other judgements—citing the value of coherence. We can give a whole slew of reasons why one theory is better than another, but there is no rulebook out there for scientists to point to which resolves the matter objectively. Even appeals to the great pragmatic value of the first theory or arguments that point out the lack of explanatory and predictive power of the space-alien theory, are still appeals to a value. No amount of observation will tell you why being pragmatic makes one theory better—it is something for which you have to argue. No matter what kind of fact we are trying to establish, it is going to be inextricably tied to the values we hold.
The second major theme of Putnam’s work is his insistence that meaning in language is, in the jargon, both external and normative. What we mean by certain utterances, he argues, can’t be explained in terms of our internal mental states alone—their meaning is derived from factors like being causally related to an external world. Although in the past Putnam has provided several detailed arguments for this position, recently he has taken to simply stating that at virtually every juncture, some amount of externality and normativity creeps into our language.
Externalism, at first glance, seems to go against the plausible idea that what we mean by our utterances is a matter of internal factors like our own ideas and intentions. What you mean by saying “I like the bank” has a lot to do with whether you want to talk about the side of a river or a building in which you apply for a loan. But Putnam will point out that there is nothing inherent in symbols (like words) which gives them content. An ant running in the sand could randomly trace out the sentence “I’m half sick of shadows” regardless of humans ever existing. Any content in those symbols, even symbols which are contextually dependent on a speaker’s intentions, derives from a very complex network of information, metaphor, and history entirely external from our mental states.
If externalism is correct then science can’t, even in principle, provide an adequate account of language. You could have a complete neural reading of someone’s brain and measure patterns in the air they produce, but still have no understanding of what they mean. Brusquely put by Putnam: “Cut the pie any way you like, meaning just ain’t in the head.”
This theme of Putnam’s work poses an additional problem for the primacy of the scientific stance because it adds a further level of entanglement, over and above the fact-value entanglement. If science can’t, in principle even, provide an adequate account of language, it seems like it is missing a crucial part of human rationality. Moreover there is the methodological trouble that science itself requires a grasp of meaning and language for us to even construct hypotheses and interpret empirical data.
Putnam’s final theme, his commitment to conceptual relativity, is closely related to the points above. In his view, there is no reason to suppose that a complete account of reality can be given using a single set of concepts. That is, it is not possible to reduce all types of explanation to one set of objective concepts. Suppose I say, “Keith drove like a maniac” and you ask me why. We would usually explain the event in terms of value-laden concepts like intention, emotion, and so on—“Keith was really stressed out”—and this seems to work perfectly fine. Now we can also take the exact same event and describe it using an entirely different set of scientific concepts— say “there was a chain of electrochemical reactions from this brain to this foot” or “there was x pressure on the accelerator which caused y torque on the wheels.” These might be true descriptions, but they simply don’t give us the whole or even a marginally complete picture of Keith driving like a maniac. We could describe every single relevant physical detail of that event and still have no explanation. Nor, according to Putnam, should we expect there to be. The full scope of reality is simply too complex to be fully described by one method of explanation.
The problem with all of this, and one that Putnam has struggled with, is what sort of picture of reality we are left with once we accept these three central arguments: the collapse of the fact-value dichotomy, the truth of semantic externalism and conceptual relativity. Richard Rorty embraced all of these positions, as did Donald Davidson, but Putnam is keen to point out why he is no Rorty or Davidson. Putnam thinks Rorty goes too far in rejecting the idea there is such a thing as a “correct representation of reality” as opposed to a merely “useful fiction,” but without something like the primacy of one set of concepts over others, there is little for Putnam to grab a hold of. He wants to believe science is getting things right, but how can he convince us we are getting closer to truth and not simply further away from where we used to be?
We could—like Putnam before the 1970s—become robust realists and simply accept that values and norms are no less a part of the world than elementary particles and mathematical objects. We could—like Putnam until the 1990s—become “internal realists” and, in a vaguely Kantian move define reality in terms of mind-dependent concepts and idealised rational categories. Or we could adopt Putnam’s current position—a more modest realism which argues that there is a mind-independent world out there and that it is compatible with our ordinary human values. Of course Putnam has his reasons for believing what he does now, and they largely derive from his faith in our ability to represent reality correctly. But the strength of his arguments convincing us to be wary of the scientific stance leave us with little left to trust in it. He is hard pressed to find a good reason not to adopt Rorty’s position.
It is this lack of a complete worldview that leaves Putnam without any disciples or a positive doctrine. There are Quineans and Rortians, but no Putnamians. But it is hard not to end up admiring Putnam’s commitment to non-commitment. He is the philosophical version of a lucidly self-aware neurotic who undermines his own most honourable enterprises. His commitment to human dignity and welfare led him politically towards the far-left and Maoism and, after an unforgiving look at the consequences of the latter, this same commitment led him to change his politics. His commitment to the reality of moral and epistemic values has caused him to shift from one ontological landscape to the next. And though in the end we don’t always know where these commitments lead us, Putnam has always forced us to think hard about wherever it is we end up.
A Kant without hubris, a Wittgenstein without quietism, an unrelenting critic, gadfly and deeply original thinker, Putnam is one of the 20th century’s true philosophical giants.
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