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On Tarski's “The Semantic Conception of Truth and the Foundations of Semantics,” (1944), Hartry Field's “Tarski's Theory of Truth” (1972), and Donald Davidson's“The Folly of Trying to Define Truth” (1977).
What is truth? Tarski gives a technical, metaphysically neutral definition for truth within a particular, well-defined language. In short, a sentence is true if it is "satisfied" by all terms in the language. A sentence with a variable would be satisfied only by certain terms: "x is red" is satisfied only by the red ones. But a sentence without a variable, if true, is satisfied by all terms: "Rose (a) is red," where (a) is a particular rose, is satisfied by that rose, because it's red, but it's also technically satisfied by my dog, by you, by Trump, etc., because none of those things interferes with the sentence being true. He had some lengthy proofs and logical language to establish this, and yes, this is weird.
One of his main reasons for doing this was to rule out things like the liar's paradox: e.g., "This sentence is false." On Tarski's analysis, a well-defined language doesn't allow this kind of sentence. As with Russell's analysis of the paradoxical "sets that aren't members of themselves," Tarski distinguishes a language from its meta-language: When you say "'Snow is white' is true," you're taking a sentence in the language (snow is white) and by putting it in quotes, you're making it an object and saying something about it, using a different language, the meta-language, which includes all the terms of the object language, but also semantic terms like "is true." Tarski's truth definition is only about an object language (which cannot include any self-reflexive terms of this sort), but is stated in a meta-language. To make this clearer, some explanations actually use different languages, e.g., "'Schnee ist weiss' is true if and only if snow is white." German here is the object language, while English is the meta-language. (But of course, as I said, everyday German couldn't really be an object language, as it's not well-formed in the required way. There would have to be no room for misunderstanding.)
Tarski claimed to be capturing our everyday notion of truth and making it more precise, with the idea that this could be extended from the formal, logical languages he was dealing with to at least formalized vocabularies within the sciences. He shunned many traditional philosophical questions, and so didn't talk much about what, if any, philosophical implications his theory provided.
Field (treated along with Davidson in the second part of our discussion) charges Tarski with misunderstanding his own project. He says that Tarski was, like many of his peers in the era of behaviorism, wary of semantic notions, i.e., he wanted to reduce talk of mind to talk of matter.
To explain: The definition I've given above applies to just one single sentence. The definition of truth for the whole language is just the collection of true sentences so defined. This is an "extensional" definition, kind of like defining "sheep" not by giving essential characteristics of a sheep, but by pointing to the whole collection of sheep. Of course, if a new animal comes along, this leaves you unable to tell if it's a sheep or not. So it's not a definition as you'd normally consider it. And Tarski's definition only then is talking about actual sentences in a particular language, and isn't giving a general definition for truth for all languages. This would require, e.g., the semantic notion of synonymy (meaning), which (on Field's analysis) is an off-limits for Tarski.
Anyway, does just pointing to a bunch of (ultimately physical) objects and saying "those are the true ones" perform the reduction that Field says Tarski is trying to accomplish? No, because (Field says) there's still the semantic notion of reference smuggled into Tarski's procedure. We can better interpret what Tarski is doing by saying that he's defining truth in terms of other semantic notions, i.e., reference, definition, and satisfaction, which Field still thinks is helpful.
Davidson's paper gives a similar analysis of Tarski: Why would you think that you can define a basic notion like "truth" in terms of more basic notions? That's not really what philosophy does. Instead, we clarify the relations between fundamental terms; we adopt the whole conceptual apparatus of truth, reference, satisfaction, etc. as a group. Each can be understood in terms of the others, but the whole group of them can only be understood as a practice. No general definition is possible.
This is the first of three episodes we'll be having on truth, and a recurrent theme that comes up that you may want to read about is the "deflationary theory of truth"; see the Stanford article on it. The idea is that instead of saying that truth is explained by metaphysics (the correspondence of a sentence to something in the world) or by the coherence of our web of beliefs (as is the case for William James; note that I've just made both of our discussions of James for eps. 20 and 22 available at the $1 level on Patreon), truth is a very uninformative notion, indicating only that you're assenting to the sentence. According to Frege, "P" and "'P' is true" say exactly the same thing. Tarski doesn't want to make exactly that move, lest the liar's paradox persist, but he's in the same ballpark, and the notion of what counts as a deflationary theory has changed over time, from Frege's "eliminative" or "disquotational" theory—i.e., you remove the quotation marks and "is true" and the sentences says the same thing—to something more subtle.
All three of these essays and the ones for next episode can be found in Truth (Oxford Readings in Philosophy)
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Tarski image by Charles Valsechi.
Dennis Matthews says
July 9, 2018 at 1:25 pmPilate: Quid est veritas?
Jesus: For all x, True(x) if and only if φ(x).
Pilate: Philosophia est mortuus.
dmf says
July 9, 2018 at 3:36 pmthanks for this, had to read Davidson in my Rorty work and not having a background in analytic philo the Tarski always escaped me, on the Heidegger/thingness question I would point not so much to the genealogical/philological aspect of language but the degree to which analytic philo takes actual/performed language and abstracts/structures it into something much more akin to a machine language, something more along the lines of what Heidegger would see as a reduction to/of calculative reasoning.
Lee Braver is interesting along these lines:
https://www.3ammagazine.com/3am/on-heidegger-wittgenstein-derrida/
Luke T says
July 14, 2018 at 9:17 pmThe following might be more germane to PEL episodes on postmodernism, but – since we’re on the subject of truth – possibly still worth the honorable mention.
https://www.washingtonpost.com/news/book-party/wp/2018/07/13/feature/can-truth-survive-this-president-an-honest-investigation/?utm_term=.f431969b8a97
Some excerpts:
Kakutani calls out lefty academics who for decades preached postmodernism and social constructivism, which argued that truth is not universal but a reflection of relative power, structural forces and personal vantage points. In the early culture wars, centered on literary studies, postmodernists rejected Enlightenment ideals as “vestiges of old patriarchal and imperialist thinking,” Kakutani writes, paving the way for today’s violence against fact in politics and science.
“It’s safe to say that Trump has never plowed through the works of Derrida, Baudrillard, or Lyotard (if he’s even heard of them),” Kakutani sniffs. But while she argues that “postmodernists are hardly to blame for all the free-floating nihilism abroad in the land,” she concedes that “dumbed-down corollaries” of postmodernist thought have been hijacked by Trump’s defenders, who use them to explain away his lies, inconsistencies and broken promises.
“In “Post-Truth,” Boston University philosophy professor Lee McIntyre has no problem affixing blame. “At some level all ideologies are an enemy of the process by which truth is discovered,” he writes. But he convincingly tracks how intelligent-design proponents and later climate deniers drew from postmodernism to undermine public perceptions of evolution and climate change. “Even if right-wing politicians and other science deniers were not reading Derrida and Foucault, the germ of the idea made its way to them: science does not have a monopoly on the truth,” he writes.
McIntyre quotes at length from mea culpas by postmodernist and social constructivist writers agonizing over what their theories have wrought, shocked that conservatives would use them for nefarious purposes. And he notes, for example, that pro-Trump troll and conspiracy theorist Mike Cernovich
, who helped popularize the “Pizzagate” lie, has forthrightly cited his unlikely influences. “Look, I read postmodernist theory in college,” Cernovich told the New Yorker in 2016. “If everything is a narrative, then we need alternatives to the dominant narrative. I don’t seem like a guy who reads [Jacques] Lacan, do I?”
dmf says
July 16, 2018 at 3:21 pmthis is like blaming Schrödinger for Deepak Chopra and rather divorced from the kinds of difficult technical issues being discussed in the podcast and related texts, the question of whether or not Truth is even a meaningful term (outside of everyday uses like talking about lies) and how is still up for grabs in philosophy as the PEL fellows help lay out for us here. Does raise the question I have of PEL which is how useful/available are highly technical/specialized bits of academic research to the lay public?
Luke T says
July 16, 2018 at 9:23 pmWell, I acknowledged up front that the piece was peripheral to the matter immediately at hand. That doesn’t mean it won’t possibly find purchase in future episodes on Truth (which apparently the PEL crew will be indulging, and soon). Even if that turns not to be the case, the themes of postmodernism and social constructivism come up again and again on PEL, so it’s worth considering as food for thought.
Maybe you can explain the Schrödinger-Chopra genealogy. I didn’t know the two were related.
dmf says
July 18, 2018 at 5:23 pmChopra uses and abuses quantum theory, not the fault of the experts in the field.