Tamar Gendler

By carefully examining one of the most famous thought experiments in the history of science—that by which Galileo is said to have refuted the Aristotelian theory that heavier bodies fall faster than lighter ones—I attempt to show that thought experiments play a distinctive role in scientific inquiry. Reasoning about particular entities within the context of an imaginary scenario can lead to rationally justified concluusions that—given the same initial information—would not be rationally justifiable on the basis of a straightforward argument.

Contemplating imaginary scenarios that evoke certain sorts of quasi‐sensory intuitions may bring us to new beliefs about contingent features of the natural world. These beliefs may be produced quasi‐observationally; the presence of a mental image may play a crucial cognitive role in the formation of the belief in question. And this albeit fallible quasi‐observational belief‐forming mechanism may, in certain contexts, be sufficiently reliable to count as a source of justification. This sheds light on the central puzzle surrounding scientific thought experiment, which is how contemplation of an imaginary scenario can lead to new knowledge about contingent features of the natural world.

By the age of two, children are able to engage in highly elaborate games of symbolic pretense, in which objects and actions in the actual world are taken to stand for objects and actions in a realm of make-believe. These games of pretense are marked by the presence of two central features, which I will call quarantining and mirroring (see also Leslie 1987; Perner 1991). Quarantining is manifest to the extent that events within the pretense-episode are taken to have effects only within that pretense-episode (e.g. the child does not expect that ‘spilling’ ( pretend) ‘tea’1 will result in the table really being wet), or more generally, to the extent that proto-beliefs and proto-attitudes concerning the pretended state of affairs are not treated as beliefs and attitudes relevant to guiding action in the actual world. Mirroring is manifest to the extent that features of the imaginary situation that have not been explicitly stipulated are derivable via features of their real-world analogues (e.g. the child does expect that if she up-ends the teapot above the table, then the table will become wet in the pretense), or, more generally to the extent that imaginative content is taken to be governed by the same sorts of restrictions that govern believed content.

Through careful analysis of a specific example, Parfit’s ‘fission argument’ for the unimportance of personal identity, I argue that our judgements concerning imaginary scenarios are likely to be unreliable when the scenarios involve disruptions of certain contingent correlations. Parfit’s argument depends on our hypothesizing away a number of facts which play a central role in our understanding and employment of the very concept under investigation; as a result, it fails to establish what Parfit claims, namely, that identity is not what matters. I argue that Parfit’s conclusion can be blocked without denying that he has presented an imaginary case where prudential concern would be rational in the absence of identity. My analysis depends on the recognition that the features that explain or justify a relation may be distinct from the features that underpin it as necessary conditions.

The aim of this article is to expand the diet of examples considered in philosophical discussions of imagination and pretense, and to offer some preliminary observations about what we might learn about the nature of imagination as a result. The article presents a number of cases involving imaginative contagion: cases where merely imagining or pretending that P has effects that we would expect only perceiving or believing that P to have. Examples are offered that involve visual imagery, motor imagery, fictional emotions, and social priming. It is suggested that imaginative contagion is a more prevalent phenomenon than has typically been recognized

I introduce and argue for the importance of a cognitive state that I call alief. An alief is, to a reasonable approximation, an innate or habitual propensity to respond to an apparent stimulus in a particular way. Recognizing the role that alief plays in our cognitive repertoire provides a framework for understanding reactions that are governed by nonconscious or automatic mechanisms, which in turn brings into proper relief the role played by reactions that are subject to conscious regulation and deliberate control.