American Journal of Philology

Recent scholarship has stressed that it is not useful to speak of Greek scientific experimentation in sweeping fashion. The Greeks did perform scientific experiments, but the quantity, quality, and areas explored varied over different periods. Thus, while at certain times such testing procedures flourished, at other times very few actual experiments were performed. So, too, certain fields were more fruitful or feasible for experimentation than others.¹ Those who tend to play down the quantity and quality of Greek scientific experimentation usually point to the Greeks' preference for speculation and theory over observation and performance of manual tasks.² Thought experiments allow the mind to range freely without leaving one's armchair or getting one's hands dirty, and that may be why such mental tests were favored by Greek thinkers, from Xenophanes onward. My purpose here is to study two thought experiments found in the Dissoi Logoi in conjunction with several related trials found in Herodotus, Xenophon, Plato, and Xenophanes. All these thought experiments make use of hypothetical human beings and deal with educational and ethical matters. Generally speaking, these hypothetical tests contrast two types of people, either individuals or larger groups, in an attempt to determine the roles played by heredity and environment in the acquisition of knowledge and moral values.

It is notoriously difficult to arrive at a precise definition of thought experiments,³ and the following is meant to be no more than a working definition. Thought experiments are, first of all, experiments.⁴ In ancient [End Page 21] Greece scientific experiments were not used as a neutral means to decide between two competing theories but rather were intended to prove or refute a hypothesis, and this is true of Greek thought experiments as well.⁵ Experiments must involve a procedure of some kind, a test consisting of at least one change deliberately introduced into the initial situation.⁶ Normally, then, an experiment is composed of (1) a thesis to be proven (or refuted), (2) a carefully contrived starting point, (3) at least one further action to be undertaken, an action affecting the original situation, and (4) a test of the results of the action(s). In a thought experiment these steps are carried out in thought, in the laboratory of the mind.⁷ The thought experimenter visualizes a situation, mentally carries out an operation, and then sees, in the mind's eye, the results. A Gedankenexperiment is not actually performed, either because there is no need to do so—common sense, intuition, or experience is sufficient to supply the results of the procedure—or because the test is one that cannot, in fact, be executed in the real world. Such experiments are not intended to prove fanciful, unlikely theories, nor are they meant to yield results which are intrinsically implausible. Generally, thought experiments are carefully imagined scenarios, which are convincing both because they have some basis in empirical observation and because they use specific details, often colorful ones, to appeal to the audience's intuition.⁸ These well-conceived tests teach us new things, even though their execution does not supply us with new empirical data of any kind.

Let us begin by looking at one such hypothetical trial in the Dissoi Logoi, an anonymous sophistic composition, written mainly in Doric, which is generally dated to the beginning of the fourth century.⁹ This [End Page 22] brief work is comprised of nine chapters, often presented in the form of double (or opposing) arguments, on subjects such as good and evil, justice and injustice, truth and falsehood, etc. Of these, chapter 6 discusses whether wisdom and virtue can be taught, and here the anonymous author touches upon the acquisition of language, while contrasting systematic teaching with informal instruction. He argues that we learn language and are not born knowing it, and offers an imaginary skeptical opponent the following proof of his claim (, 6.12): if one were to send a newborn Greek infant off to Persia and raise him there, without his hearing Greek, he would speak Persian; and if one were to bring a Persian baby to Greece, he would speak Greek (, 6.12...