Is 'is' ambiguous?

One of the essential components of modern logic is the view, standardly attributed to Frege and Russell, that 'is' is ambiguous: 'is' has the senses of
(i) identity (Mark Twain is Samuel Clemens; in other words, Mark Twain = Samuel Clemens),
(ii) predication (Mark Twain is an author), and
(iii) existence (Mark Twain is; in other words, Mark Twain exists), and
(iv) class inclusion (Authors are artists).

After grading a batch of logic problem sets, I'm wondering whether (i) and (ii) really are ambiguous; more specifically, how the senses of identity and predication fare with respect to the standard ambiguity tests. As I've mentioned several times before on this blog, one of the most widely-accepted ambiguity tests is the conjunction-reduction (or 'no crossed readings') test. The basic idea can be illustrated by an example: 'Alice has a bat' can mean she has a flying pet or a new baseball bat; 'Bob has a bat' has the same two possible readings, with Bob instead of Alice. However, 'Alice and Bob have bats' cannot mean that one has a baseball bat, and the other has a pet flying mammal.

Now let's think about 'is'.
'Mark Twain is Samuel Clemens' has a true reading, and
'Mark Twain is a famous author' has a true reading.
But what about 'Mark Twain is Samuel Clemens and a famous author'?
This sounds zeugmatic to me, confirming the Frege-Russell view of 'is' as ambiguous. However, many of my logic students wrote something analogous to this on their most recent problem set, when asked to translate a particular sentence of first-order logic into English. Student responses to logic problem sets are probably some of the worst data imaginable for this kind of question, but it did make me wonder whether my observations about 'is' in English are very theory-laden, ruined by years of logic and logically-inspired philosophy. What do other folks think about 'Mark Twain is Samuel Clemens and a famous author'?

Do any languages mark the use/mention distinction in speech?

In written English, we mark the distinction between using an expression and mentioning it using quotation marks: 'Chicago' has 7 letters, but Chicago does not. In other words, we can use quotation marks to disambiguate between use and mention.

For various reasons, I am interested in ambiguity tests: ways to diagnose whether a particular expression really is ambiguous or not. One common, widely-accepted (I think) test appeals to different languages: if the e.g. English expression you're interested in is in fact ambiguous, then it should be translated by two unrelated words in at least some other languages. For example, 'bank' is ambiguous in English, and it is translated by 'Bank' and 'Ufer' in German.

After reading a batch of student papers about the definition of 'health,' I was struck by their complete lack of inclination to distinguish use and mention. So then I thought about the ambiguity test -- does any spoken language disambiguate use and mention morphologically (without saying 'the word...' or 'the sentence...')? I posted the question at Ask A Linguist, and the three people who responded said they did not know of any. Does anybody out there know of one? (And it would be strange if it were just one or two languages...)

If there aren't (m)any such languages, then it looks like this could be a counterexample to that particular ambiguity test.

Carnap on the internets

There is no internet acronym that adequately captures my feelings about this post, which I found via my google alert for Carnap:


"There has never been a scientific scam in the history of mankind as big as the science swindle of "climate change." Nothing comes close. Modern scientific hustles like mesmerism, phrenology, eugenics, the Piltdown man, and even Lysenkoism, pale in comparison to the flimflam of anthropomorphic global warming (AGW).

There was, however, one astonishing episode in the early part of the 20th century in mathematics and logic which conceptually roughly parallels the current crisis of science behind AGW. It was the destruction of the dream of the Vienna Circle of the completion of logic. Kurt Gödel, the German mathematician and philosopher, put the philosophical fantasy of "the elimination of metaphysics through the logical analysis of language" to rest[i].

Gödel's two "Incompleteness Theorems" exposed fundamental flaws in the foundations of a school of philosophy known as Logical Positivism. In a somewhat similar vein, the release of the e-mails for the University of East Anglia precipitated the collapse of the house of cards of the Intergovernmental Panel on Climate Change (IPCC) and the "science" behind AGW. ..."


If that's not enough enlightenment for you, the original post continues for several more paragraphs.

Name that quote, plus a request for history of analytic literature

Name the author and work for the following two quotes:

(1) "that is a priori which we can maintain in the face of all experience, come what will."

(2) "the whole body of our conceptual interpretations form a sort of hierarchy or pyramid with the most comprehensive, such as those of logic, at the top, and the least general, such as 'swans' etc. at the bottom; that with the complex system of interrelated concepts, we approach particular experiences and attempt to fit them, somewhere and somehow... Persistent failure leads to readjustment... The higher up a concept stands in our pyramid, the more reluctant we are to disturb it, because the more radical and far-reaching the results will be if we abandon it..."


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Answer: C.I. Lewis, Mind and the World-Order (1929): p. 231 and pp.305-6.

Now for the request. Quote (1) sounds very similar to Quine's 'an analytic sentence is one held true come what may' (especially because for Lewis the analytic and the a priori are coextensive). Quote (2) echoes Quine's description of the web of belief (with the major difference that the nodes of Quine's web are claims, not concepts). Does anyone know of a paper or book chapter that describes in detail the relationship between Quine and C.I. Lewis -- specifically Lewis's influence on Quine? Thanks in advance!

Do animals pretend?

This is my first foray into Sunday cat blogging. Here goes.

Many philosophers have spent a fair amount of time thinking about pretense -- what exactly it is, and how to apply a theory of pretense to various areas of philosophical interest (e.g. perhaps we are playing a game of pretend when we talk about the natural numbers).

I was just watching my cat play with a fuzzy cat toy. The cat, in some sense, realizes that the fuzzy ball is not a mouse (or whatever). However, when it is playing with the toy, it will temporarily exhibit many of the behaviors that it would exhibit toward a real mouse -- e.g., it hides behind furniture so that the toy won't 'see' it.

All the philosophical discussions of pretense with which I am familiar are restricted to human pretense. But given the kinds of things I see with my cat, and given that pretense occurs fairly early in childhood development (sophisticated multi-person pretend games start around 3 1/2), it seems at least possible that animals engage in pretense too.

And if my cat isn't engaged in a pretense, then what exactly is it doing?

New philosophy of physics blog

I somehow missed this: there's a new philosophy of physics blog by my erstwhile office-mate Chris Wüthrich, who's now at UCSD. It's cleverly titled "Taking up Spacetime," and it looks promising -- he has a good recent post up about the notion of structure.

logic teaching question

I'm teaching Symbolic Logic this term, and we just introduced the notion that two syntactically distinct sentences can mean exactly the same thing (e.g. DeMorgan's Laws). In class yesterday, I asked the students to come up with a criterion for when two sentences are identical in meaning. We eventually reached the "official" answer: S_1 and S_2 are synonymous just in case they have the same truth-value in all models (ok, we're not using the notion of models; for us, it's "... in all possible arrangements of the board" in Tarski's World -- we're using Barwise and Etchemendy's Language, Proof, and Logic.)

Along the way to the official answer, though, a student gave the following characterization:

Sentences S_1 and S_2 are synonymous just in case the set of all sentences that follow from* S_1 is identical to the set of all sentences that follow from S_2.

After class, I jotted down a proof-sketch showing that the student's characterization is equivalent to the "official" one. But I'm not 100% confident in it, so I'm just curious whether anyone can see a counter-example (i.e. are there any 2 sentences that meet one characterization but not the other?).
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* EDIT: As Bryan made me realize in the comments, I should specify that 'follows from' here is semantic, not syntactic/ proof-theoretic; i.e. 'Conclusion C follows from premise P' means that every model (or world, or construction, or whatever it is that makes sentences true in your formal semantics) in which P is true is also a model in which C is true.

What type of contradiction, if any, is this?

Discuss.

Appiah, X-Phi, and a Kripkean intuition

I have found Kwame Anthony Appiah's work on experimental philosophy insightful and sensible, and I have learned a great deal from it. I find most of his claims very plausible, but one empirical assertion stood out as questionable: there is a diversity of intuitions among Anglophone philosophers about the Schmidt-Gödel thought-experiment.

"When Eduoard Machery and colleagues posed a famous thought experiment of Kripke’s to students, they found that those from Hong Kong had quite a different pattern of response than those from New Jersey. But my guess is that in most cases, the results would shore up the intuition it was meant to pump; and that, where it did not, philosophers, too, have already been left divided." (2007 APA Presidential Address, section IX)

"Here’s the thing about the theory of reference: Versions of both views — Kripke’s and the one he was challenging — have plentiful adherents among philosophers. Both intuitions have their advocates."("The New New Philosophy," NYT Magazine, Dec 9 2007)

(Emphases mine, in both quotations.) It's certainly true that there is nothing close to unanimity among Anglophone philosophers on the correct theory of reference. However, I do have the impression that, sociologically speaking, philosophers do overwhelmingly have the intuition that "Gödel" does not refer to Schmidt in Kripke's thought experiment. People with descriptivist proclivities accept the intuition, but then try to accommodate (or explain away?) that intuition within a broadly descriptivist framework. Or am I wrong about this sociological pattern?

survey says: there are analytic truths

I imagine many readers are already aware, but the results of the Philosophical Survey are now available here.

The biggest surprise for me was on the question 'Analytic-synthetic distinction: yes or no?': 65% said yes or lean toward yes, and only 27% said no or lean towards no.

This is not an unqualified sociological victory for Carnapophiles, because Chalmers notes in the discussion that many of the 'yes' respondents included a comment along the lines of '... but the distinction does no substantive philosophical work' -- which is precisely Quine's later position (seen perhaps most clearly in his Schilpp Library of Living Philosophers volume).