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Jonathan Schaffer gives lecture on metaphysics, language 

Jonathan Schaffer gives lecture on metaphysics, language 


On Monday, the Department of Philosophy Larwill Lecture sponsored Jonathan Schaffer ’93, a professor of philosophy at Rutgers University, who gave a lecture on ontology: the philosophical study of existence. The lecture, titled “On What There Is, Was and Could Be” was held in Philomathesian Hall in Ascension Hall. Approximately 40 students and faculty members attended, filling nearly every seat in the room. 

Professor of Philosophy Hans Lottenbach introduced the lecture, beginning with a reminder that the Larwill Lecture in philosophy was endowed by Joseph H. Lago (Class of 1855). Lottenbach then introduced Schaffer, highlighting his emphasis on metaphysics, epistemology and research in both the philosophy of language and the philosophy of science. 

At the start of his lecture, Schaffer dedicated his speech to Cyrus Banning H’94, his first philosophy professor. He then began by discussing Willard Van Orman Quine, whose philosophy focused on metaphysics within analytic philosophy. Schaffer read aloud a paragraph from Quine’s philosophy, which discussed the paradox of non-being — the question of whether one can meaningfully deny that anything exists. 

“It’s sometimes said that philosophy is a series of footnotes to Plato,” Schaffer said. “But I feel like my career has been a series of footnotes to this first paragraph from Quine. So maybe, in a sense, a series of footnotes to footnotes to Plato.” 

Schaffer said that this first paragraph identifies the question “what is there?” and resolves it with the answer “everything, and everyone will accept that as true.” Throughout the remainder of the lecture, Schaffer intended to prove that some things did not exist, contrary to other philosophical theories. 

Using the example of Pegasus, a winged horse from Greek mythology, Schaffer expanded on how the question of existence and the philosophy of language are closely related. “To be able to meaningfully say that Pegasus does not exist, we have to be able to meaningfully speak of Pegasus,” Schaffer said. “But to be able to meaningfully speak of Pegasus, the name Pegasus must have meaning… We cannot coherently deny the existence of anything that we can name. Because in naming it, there must be an it that we’re naming.”

A majority of Schaffer’s lecture focused on model theoretic semantics of natural language, a form of semantics that interprets the truth-values of sentences through domains (a collection or set of objects) and quantifiers (which range over objects in the domain). “If you’re naming something, there’s a thing in the domain that’s bearing it, and you can quantify over it,” Schaffer said. 

Throughout the lecture, Schaffer referenced five example claims regarding the existence of certain things: 1. Pegasus exists; 2. Pegasus could exist; 3. Plato exists; 4. Plato existed; 5. Putin exists. Schaffer applied certain modifiers to the five claims, which changes the potential truth-value of each sentence. “Root ‘exist’ cries out for three sets of information on this entity,” Schaffer explained. “If you feed ‘Putin,’ ‘actuality’ and ‘2024’ in, it spits out a truth, because Putin actually exists. For Plato, if you feed ‘actuality’ and ‘2024’ into existence, that’s a false because Plato doesn’t actually exist in 2024.” Through these quantifiers, Schaffer determined the truth-value for each claim, demonstrating that claim three (Plato exists) is false, compared to claim four (Plato existed), which is true. 

“I’m denying that ‘what there is’ is the right question to be asking,” Schaffer said regarding language for these claims. “The question really ought to have been, ‘what root exists?’” 

Through this philosophy of logic and language, Schaffer argued that some things do not exist, such as Pegasus, but could exist in theory. A key part of the lecture was the distinction between logic and natural language, as Schaffer stated that philosophers in the past have had incorrect perspectives about the relation between logic and natural language. 

“Once you see that tense and mode are hiding in natural language, you’ll see that we need to be much more careful about how we try to correlate expressions of natural language with anything,” he said. 

At the end of the lecture, a Q&A was held, which lasted almost as long as the lecture itself. Both Professor of Philosophy Joel Richeimer and Professor of Philosophy Yang Xiao challenged Schaffer on some of his ideas, and several students proposed questions and theories about the lecture as well. 


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