Roy Sorensen

You receive a pink packet from Miss Lead, a notoriously deceptive truth-teller. You know that if you open the packet and do not find blank pages, then you will justifiably change your mind about the evidence being misleading. Indeed, you will infer that your previous fears about misleading evidence were themselves founded on misleading evidence. Should you open the pink packet? No, answers an advocate of self-censorship. Yes, answers an advocate of the principle that you should base conclusions on all the available evidence. Your final deliberations will be guided by Gilbert Harman’s Thought. Ultimately, the case against opening the packet prevails.

This article considers question‐begging's opposite fallacy. Instead of relying on my beliefs for my premises when I should be using my adversary's beliefs, I rely on my adversary's beliefs when I should rely on my own. Just as question‐begging emerges from egocentrism, its opposite emerges from other‐centrism. Stepping into the other person's shoes is an effective strategy for understanding him. But you must return to your own shoes when forming your beliefs. Evidence is agent centered. Other‐centric reasoning is most striking when both parties partake simultaneously. We are then treated to the spectacle of each side using the other's premises to establish its conclusion. These remarkable debates arise regularly when there is open disagreement about whether a right‐conferring relationship has ended. Those who contend the relationship is abrogated will be tempted to stand on the rights persistently credited to them by their adversary.

Peter Slezak and William Boos have independently advanced a novel interpretation of Descartes's "cogito". The interpretation portrays the "cogito" as a diagonal deduction and emphasizes its resemblance to Godel's theorem and the Liar. I object that this approach is flawed by the fact that it assigns 'Buridan sentences' a legitimate role in Descartes's philosophy. The paradoxical nature of these sentences would have the peculiar result of undermining Descartes's "cogito" while enabling him to "disprove" God's existence.

This chapter focuses on armchair inquiry. Thought experiment has the feel of clairvoyance, thus eliciting awe in some and suspicion in others. But the wonder of thought experiment is just a special case of our vague puzzlement about how a question could be answered by merely thinking. There is no mystery when investigators look, measure, and manipulate. Their answers come from the news borne by observation and experiment. But if you just ponder, then the information you have leaving the armchair is the same as the information you had when you sat down. It is argued that part of our wonder is based on a modal fallacy. The theories of armchair inquiry that promise answers to the legitimate portion of our wonder are surveyed. Finally, a cleansing model of rationality that sets the stage for a detailed analysis of how thought experiments work is developed.

This chapter lays out a classification scheme for thought experiments. A good scheme consolidates knowledge in a way that minimizes the demand on your memory and expedites the acquisition of new knowledge by raising helpful leading questions. Thought experiments are all reducible to two highly specific forms of paradox — one targeting statements implying necessities, the other targeting statements implying possibilities. By treating a thought experiment as a stylized paradox, the idea that it reveals inconsistencies is matured. The chapter also exposes the structure of our ensuing ambivalence, as well as the structure of resolutions.

Drawing inspiration from the ethical pluralism of G. E. Moore's Principia Ethica, I contend that one empty world can be morally better than another. By ?empty? I mean that it is devoid of concrete entities (things that have a position in space or time). These worlds have no thickets or thimbles, no thinkers, no thoughts. Infinitely many of these worlds have laws of nature, abstract entities, and perhaps, space and time. These non-concrete differences are enough to make some of them better than others. 1I thank Walter Sinnott-Armstrong, John Carroll, and Gideon Rosen for their comments and suggestions

This chapter presents and motivates the issues surrounding thought experiments by assembling the case against their use. It begins by exploring the more specific charge that thought experiment is just introspection, then concentrates on the charge that it is merely an atavistic appeal to ordinary language. Even if thought experiment is distinct from either of these methods, it strongly resembles them. Hence, details of both introspection and the appeal to ordinary language will be discussed in the hope of illuminating thought experiment at least by analogy. Finally, a more general problem about the informativeness of thought experiment is developed.

Stepping into the other guy's shoes works best when you resemble him. After all, the procedure is to use yourself as a model: in goes hypothetical beliefs and desires, out comes hypothetical actions and revised beliefs and desires. If you are structurally analogous to the empathee, then accurate inputs generate accurate outputs-just as with any other simulation. The greater the degree of isomorphism, the more dependable and precise the results. This sensitivity to degrees of resemblance suggests that the method of empathy works best for average people. The advantage of being a small but representative sample of the population will create a bootstrap effect. For as average people prosper, there will be more average descendants and so the degree of resemblance in subsequent generations will snowball. Each increment in like-mindedness further enhances the reliability and validity of mental simulation. With each circuit along the spiral, there is tighter and tighter bunching and hence further empowerment of empathy. The method is self-strengthening and eventually molds a population of hyper-similar individuals-which partly solves the problem of other minds

Stepping into the other guy’s shoes works best when you resemble him. After all, the procedure is to use yourself as a model: in goes hypothetical beliefs and desires, out comes hypothetical actions and revised beliefs and desires. If you are structurally analogous to the empathee, then accurate inputs generate accurate outputs---just as with any other simulation. The greater the degree of isomorphism, the more dependable and precise the results. This sensitivity to degrees of resemblance suggests that the method of empathy works best for average people. The advantage of being a small but representative sample of the population will create a bootstrap effect. For as average people prosper, there will be more average descendants and so the degree of resemblance in subsequent generations will snowball. Each increment in like-mindedness further enhances the reliability and validity of mental simulation. With each circuit along the spiral, there is tighter and tighter bunching and hence further empowerment of empathy. The method is self-strengthening and eventually molds a population of hyper-similar individuals---which partly solves the problem of other minds.

This chapter focuses on the views of Australian philosopher-physicist Ernst Mach, the earliest and most systematic writer on thought experiments. It discusses Mach's response to the problem of informativeness. It then details the book's disagreements with Mach. It is argued that Mach's mistakes can be traced to his sensationalism and a one-sided diet of examples. His sensationalism led him to overemphasize the mentalistic aspects of thought experiment and to throw away tools needed to explain its genuinely a priori features. Perhaps because of this, Mach's attention gravitated toward thought experiments he could explain and away from the recalcitrant normative examples. To get a complete account of thought experiments, we should reject sensationalism and consider how armchair inquiry works in general.

This chapter illustrates the power of thought experiments by assembling influential thought experiments from the history of science. It lays out the book's plan to understand philosophical thought experiments by concentrating on their resemblance to scientific relatives. Points of difference between philosophical and scientific thought experiments give a preview of obstacles that must be overcome in the course of the campaign. Naive and sophisticated reservations about the philosophical cases are registered for the same purpose.

This chapter examines the hazards and pseudohazards of thought experiment. It attacks most skepticism about thought experiment as arbitrary. It argues that once the standards that are customary for compasses, stethoscopes, and other testing devices are applied, thought experiments measure up. They should be used as part of a diversified portfolio of techniques. Although all these devices are individually susceptible to abuse, fallacy, and error, they provide a network of cross-checks that make for impressive collective reliability.