Frege and Wittgenstein on Sense, Reference and Thought

1. Frege and Wittgenstein on Sense, Reference and Thought Reading Frege’s “On Sense and Reference” and “The Thought” in comparison with Tractatus 3 through 4.243

2. Senses and References of Names • In “On Sense and Reference,” Frege argued that names must have senses in addition to references. See pages 56 through 58. • Why didn’t Wittgenstein believe that names have senses? See T 3.2 through 3.3. • What does 3.3 mean in Tractatus?

3. More on Senses and References • On page 60 of “On Sense and Reference,” Frege draws an analogy between ideas, senses and references on the one hand and the images associated with a reflecting telescope on the other. Can you say precisely what that analogy is? Are the details of the analogy correct? How would Wittgenstein have replied to the analogy? See T 3.22 through 3.261.

4. A Skeptical Problem and Its Proposed Solution • On pages 61 and 62 of “On sense and reference,” Frege takes up a skeptical problem. What is that problem? • How does Frege respond to the problem? • What, do you think, is the solution that Frege here has in mind? • Is there a similar problem and proposed solution in Frege’s “The Thought?”

5. Sense and Reference • On page 62 of “On Sense and Reference,” Frege argues that the thought cannot be the referent of a sentence and that the thought expressed by a sentence must be its sense. • What is Frege’s argument? • What principles does Frege assume? • Would Wittgenstein agree with Frege’s conclusion? See T 4.0621.

6. Senses and References • On page 63, Frege argues that sentences have referents. What is his argument for this conclusion? • According to Frege, what are the referents of sentences? • Would Wittgenstein agree with this conclusion? See T 3.142 and 3.221.

7. Barwise and Perry, “The Slingshot” • This argument is attributed to Frege by Alonzo Church. Its conclusion is that, if sentences name facts, then all true sentences name the same fact. • Assumptions: [1] Logically equivalent sentences have the same referents. [2] The referent of a sentence is determined compositionally. • Remember: {x: x = 1 and R} is a class abstract.

8. “The Slingshot” Argument • Let R and S be two true sentences. The following listed expressions all have the same referent. • R • {1} = {x : x = 1 and R} By Log. Equiv. • {1} = {1} By Compositionality; R is true • {1} = {x: x =1 and S} By Compositionality; S is both true. • S By Logical Equivalence • Therefore, R and S refer to the same thing.

9. Wittgenstein and the Slingshot • How would Wittgenstein respond to the Slingshot Argument?

10. Frege on the Correspondence Theory • On page 291 of “The Thought,” Frege argued against a correspondence theory of truth. What was his argument?

11. Frege’s Arguments for an Outer World • These arguments appear on pages 301 through 311 of “The Thought.”