Roy Sorensen

A thorough telepath in an otherwise mindless world would have an observational basis for solipsism. He would perceive an absence of other minds. How would things appear to the lone telepath? Given sufficient scepticism about introspection, exactly as they now seem to you. This perceptual solipsist would exclude other minds on the basis of evidence rather than the absence of evidence. He would be open‐minded, ready to revise his opinion as rapidly as any perceiver. Any intransigence would be a side‐effect of his theory about the senses. Temperamentally, he need not be a loner. The solipsist's ethics could be altruistic, his politics democratic, and his social preferences gregarious. At the same time, his solipsism would inform his hopes for immortality, his career choice and his means of communication.1.

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.

Imagine a child playing in the afternoon sun, suddenly jerking her arm one way then the other, trying to catch her shadow out. The game, the child soon learns, is one that she can never win. Her shadow moves the moment she does. Such childish games father common sense wisdom; when things move, so do their shadows. Or do they? A spinning sphere casts a shadow. But does its shadow also spin? The question takes you by surprise. Surely not? you think. But then again, why not? This is the trope of Sorensen’s work. A seemingly simple phenomenon is probed in just the right way and, without warning, you are unsure what to say.