Typeset your answers neatly and submit a hardcopy solution at the beginning of class on 2012-04-26. You should consider using LaTeX, but I will not force you to do so.

Please note that many of these questions are not answerable solely from the course notes and textbooks. You may actually need to do some research—the web is fine. Remember to cite your sources. Also note that just because you pull data from a reputable source doesn't mean your answer will be good enough for full credit, let alone correct. Make sure your response answers the question, and answers it thoroughly. But be brief!

The readings for this assignment are GEB, Chapters 10-14 and Eric Baum's What is Thought, Chapters 1-4. When reading Baum, read Chapters 1 and 3 carefully, but you need only get the gist of Chapters 2 and 4.

1. Why do people tend to confuse the statements "computers can only do what you tell them to do" and "computers cannot think"? Why are they actually fundamentally different?
2. Give three examples each of systems whose components have a canceling effect on each other and systems whose components' behavior have huge high-level consequences.
3. What are epiphenomena? Give five examples other than those given in GEB (e.g., pressure, temperature).
4. What is the difference between Achilles' MU and the Tortoise's MU in Ant Fugue?
5. Define signals, symbols, passive symbols, and active symbols. Relate these concepts to ant colonies, language, and the brain, using the notions of levels of description, critical mass (regarding the formation of signals), and purposeful behavior. At what level do conscious systems operate?
6. Why is it that the mind has an easy time intermingling fact and fantasy? (Answer in terms of Hofstadter's descriptions of intensionality and extensionality.)
7. In Aria with Diverse Variations, Achilles makes the claim that it "never takes an infinite number of reasons to account for some arithmetical truth." What motivates him to make this claim? Is it true? Relate this to Baum's discussion of MDL in Section 4.2 of his book.
8. Translate Hofstadter's TWO-TO-THE-THREE-TO-THE BlooP procedure into the programming language of your choice.
9. Does Searle object to the Turing Test as a criterion by which a machine can said to be thinking? If so, what is his main objection?
10. What is required for building a program (machine, or robot) that can resolve the meaning of "it" in the sentences "Mary saw a dog in the window; she wanted it." and "Mary saw a dog in the window; she pressed her nose against it."?