Kripke's Arguments Against Descriptivism

Hello! Welcome to your next lesson.

Last time, we introduced Saul Kripke's crucial distinction between rigid and non-rigid designators. We established that proper names (like "Aristotle") are rigid—they refer to the same individual across all possible worlds—while most definite descriptions (like "the teacher of Alexander the Great") are non-rigid, as they can pick out different individuals in different worlds.

Today, we'll see why this distinction is so powerful. Kripke developed it as a weapon against the long-reigning theory of how proper names get their meaning: descriptivism. This lesson directly addresses the learning outcome: Explain Kripke's modal and epistemic arguments against descriptivist theories of proper names. We will see how Kripke uses a series of ingenious arguments and thought experiments to dismantle this traditional view, paving the way for his own revolutionary account.

1. Recapping Rigidity and Introducing the Target: Descriptivism

First, a quick visual reminder of what we learned in the last lesson.

The view that Kripke attacks, descriptivism, claims that the meaning of a proper name is equivalent to a definite description or a cluster of descriptions associated with that name by speakers. For example, a simple descriptivist might say the meaning of "Aristotle" is "the teacher of Alexander the Great and student of Plato."

By the early 1970s, the most sophisticated version of this view was John Searle's "cluster theory," which held that a name refers to whatever object satisfies a sufficient number of the most important descriptions in the associated cluster. This is the primary target of Kripke's attack.

To get a clear picture of this cluster theory, let's watch a short introduction.

As you saw, the cluster theory can be broken down into a set of claims about how names relate to properties (or descriptions). Now, we will examine Kripke's powerful arguments against these claims. Kripke's case is a masterclass in philosophical argumentation, and given your background in mathematics, you will likely appreciate the logical precision of his attack.

Kripke's critique can be organized into three main lines of argument:

1. The Modal Argument: From the necessity of identity and the nature of rigid designators.
2. The Epistemic Argument: From the distinction between a priori and a posteriori knowledge.
3. The Semantic Argument: From cases of ignorance and error.

Let's work through them one by one.

2. The Modal Argument: Names Aren't Descriptions

The modal argument is the most direct application of the concept of rigid designation. It's a beautifully simple but devastating argument. For a very precise, logical breakdown, let's turn to these lecture notes.

Let's restate that elegant argument:

• Premise 1: Ordinary proper names are rigid designators. (e.g., 'Aristotle' refers to Aristotle in all worlds).
• Premise 2: Ordinary definite descriptions are not rigid designators. (e.g., 'the greatest philosopher of antiquity' could have referred to Plato in another world).
• Premise 3: If two expressions have different modal profiles (one is rigid, one is not), they cannot have the same meaning.
• Conclusion: Therefore, ordinary proper names do not mean the same thing as any definite description.

This attacks Thesis 6 from the video ("It is necessary that the referent has these properties"). If "Aristotle" just meant "the teacher of Alexander the Great," then the statement "Aristotle taught Alexander the Great" would be necessarily true. But it's not! We can easily imagine a possible world where Aristotle decided to become a hermit instead. He would still be Aristotle, but he wouldn't be the teacher of Alexander.

The following clip walks through this exact point.

3. The Epistemic Argument: We Discover Facts, We Don't Define Them

The next argument shifts from what is necessary to what is knowable a priori (knowable through reason alone, without experience).

If "Aristotle" were synonymous with a description like "the teacher of Alexander," then the statement "Aristotle was the teacher of Alexander" would be an analytic truth, like "Bachelors are unmarried men." We should be able to know it a priori.

But is that the case? Of course not. We know that Aristotle taught Alexander through historical, empirical investigation (a posteriori). It's a fact we discover about the world, not a fact we know by definition.

This is Kripke's epistemic argument, which targets Thesis 5 ("It is a priori that the referent has these properties").

As the notes explain, descriptivism gets the epistemic status of our beliefs wrong. The properties we associate with historical figures are things we learn, often with difficulty; they are not definitional truths we can know from our armchair.

4. The Semantic Argument: The Famous Case of Gödel and Schmidt

Kripke's final, and perhaps most famous, line of attack concerns whether the descriptions we associate with a name actually succeed in picking out the correct individual. He argues they often fail, either due to our ignorance or our error.

• Argument from Ignorance: I can successfully refer to "Richard Feynman" even if the only description I associate with the name is "a famous physicist," which is not unique and doesn't pick anyone out. Descriptivism would wrongly imply I am not referring to anyone.
• Argument from Error: If the main description I associate with "Einstein" is "the inventor of the atomic bomb" (which is false), I am still referring to Einstein, not Oppenheimer. Descriptivism would wrongly imply I am referring to Oppenheimer.

Kripke crystallizes this with a brilliant thought experiment.

Let's analyze the Gödel-Schmidt case:

• The Scenario: Suppose the man we call "Gödel" stole the proof of the incompleteness theorem from an unknown mathematician named Schmidt.
• The Description: The primary description we associate with the name "Gödel" is "the man who proved the incompleteness of arithmetic." In our fictional scenario, this description is uniquely satisfied by Schmidt.
• The Descriptivist Prediction: Descriptivism (specifically Theses 3 & 4 from the video) predicts that when we use the name "Gödel," we are actually referring to Schmidt.
• Kripke's Point: This prediction is clearly wrong. Intuitively, when we say, "In this scenario, Gödel didn't prove the theorem," we are making a statement about Gödel, the man who stole the proof, not about Schmidt. The name "Gödel" still refers to Gödel, even when the main description we have in our heads points to someone else.

This thought experiment powerfully demonstrates that reference is not fixed by speaker's beliefs or descriptions.

Conclusion

In this lesson, we have dissected Kripke's classic and powerful critique of descriptivism. By leveraging concepts of modality and epistemology, he demonstrated that the long-standing view that a name's meaning is a description is fundamentally flawed.

Key Takeaways:

• Descriptivism holds that a proper name's meaning is synonymous with a description (or cluster of descriptions) associated with it by speakers.
• The Modal Argument: Since names are rigid designators and descriptions are typically non-rigid, they cannot have the same meaning. It is not a necessary truth that Aristotle had the properties we associate with him.
• The Epistemic Argument: Facts associated with a name (e.g., "Gödel proved the incompleteness theorem") are known a posteriori (through experience), not a priori (by definition). Descriptivism incorrectly treats them as a priori truths.
• The Semantic Argument: Through thought experiments like the Gödel-Schmidt case, Kripke shows that a name refers to its bearer even if the descriptions associated with the name are false or point to someone else. Our referential intentions are not determined by the descriptions we hold.

Preview of the Next Lesson:

Kripke's arguments are devastatingly effective, but they are purely negative—they tear down the old theory. This naturally raises the question: If descriptions don't determine what a name refers to, what does? In our next lesson, we will explore Kripke's positive proposal: the causal-historical theory of reference. This theory suggests that names refer via a chain of communication stretching back from our current use to an initial "baptism" of the object.