Nenad Miscevic was born in Zagreb, and studied in Zagreb, Chicago, Pariz and Ljubljana. He taught philosophy first in his native Croatia, and then in Slovenia and Hungary, with some visiting teaching in Triest, Geneva and Fribourg in Switzerland. He works mostly in epistemology and in political philosophy.

Nenad Miscevic was born in Zagreb, and studied in Zagreb, Chicago, Pariz and Ljubljana. He taught philosophy first in his native Croatia, and then in Slovenia and Hungary, with some visiting teaching in Triest, Geneva and Fribourg in Switzerland. He works mostly in epistemology and in political philosophy.

A Post by Nenad Miscevic.

How can a theory of imagination help us understand thought experiments (“TEs”, for short)? In particular, can it help us answer the question of where they belong and what is their wider genus?  Where should we locate TEs on a wider map of related activities? What are their closest relatives? Finding an answer is an important task that has not been undertaken seriously until now (but see on the Junkyard the posts by Eric Peterson and Mike Stuart, and Maks Del Mar).

I propose that we start from the fact that TEs essentially involve imagination.[1] This fact can help us with our task. There is a wide range of intellectual activities that show some analogy with TEs and which can be brought under the same wider genus as our target imaginative exercises; some of them are occasionally treated as being TE themselves, by authors ranging from Ernst Mach to our present day colleagues like David Davies.[2] Some hundred years ago, more precisely in 1905, Ernst Mach has proposed a list of various relatives of scientific and philosophical TEs, even describing them as TEs themselves:

Besides physical experiments there are others that are extensively used at a higher intellectual level, namely thought experiments. The planner, the builder of castles in the air, the novelist, the author of social and technological utopias is experimenting with thoughts; so, too, is the hard-headed merchant, the serious inventor and the enquirer. All of them imagine conditions, and connect with them their expectations and surmise of certain consequences: they gain a thought experiment. However, while the former combine in fantasy certain conditions that never occur together in reality, or imagine these conditions accompanied by consequences that are not connected with them, the latter, whose ideas are good representations of the facts, will keep fairly close to reality in their thinking. Indeed, it is the more or less non-arbitrary representation of facts in our ideas that make thought experiments possible. (1976, p. 29)

I propose that we follow Mach in opting for a very wide genus in locating TEs, but that we keep the name “thought experiments” for the narrower, more controlled, cognitively focused species. Let me use Tamar Szabo Gendler's characterization of the narrow species. Performing a TE involves “reasoning about a particular set of circumstances“ (2004, p. 1155) Most importantly, “the reasoner’s mode of access to the scenario is via imagination rather than via observation“ and “contemplation of the scenario takes place with a specific purpose: the confirmation or disconfirmation of some hypothesis or theory.“ (Ibid.).

So, what about other, similar activities, guided by different, not narrowly cognitive goals? Planning, building of social and technological utopias-castles in the air, conceiving of the plot of a novel or drama, religious imaginative meditations? They come very close to TEs, as authors from Mach through Elgin to Davies have noticed. I propose that they offer the relevant genus, encompassing TEs as a species. We then need a name for this wider genus; I propose “imaginative enactments in thought”, “IET” for short. Such enacting happens in theoretical contexts, in everyday understanding of others, in practical planning, maybe elsewhere in the vicinity of planning.

In order to keep the characterization focused, let me exclude fantasizing for pure pleasure, also a kind of imaginative enactment. So, let me require that the enactment be done with some purpose (cognitive, practical, and so on) that goes beyond purely hedonic fantasizing.

Let us distinguish two families of such activities of imagination: first, those that have as their primary purpose increase of knowledge like the strict TEs do, and those that have other purposes, but in their construction resemble strict TEs.

One example from the first family comes from linguistics. In the field research, the linguist presents a string of sounds (phonemes, letters) to the native speaker of the language investigated and asks her questions. Typically, she might ask the speaker to decide if such-and-such would be a sentence of his language. The native speaker might react immediately, or try to re-imagine producing or hearing the sentence himself. The verdict will be an intuition, for instance, yes, this is a sentence of my language. The appeal to such intuitions has been playing a paramount role within Chomsky’s paradigm of linguistic research.

But there is much more in the second family. A very wide area of imaginative enactments is to be encountered in fiction, either literary, or theatrical (drama, opera, ballet), cinematographic or even perhaps in painting. The primary function of the presentation might be artistic and/or enjoyment inducing, normally there will be a cognitive point as well. Take “The Matrix,” a movie that offers a scenario in which brains are manipulated by evil scientists and induced to quasi-perceive and accept a completely illusory reality. It is very close to the famous TE of the Evil Demon, due to Descartes, and even closer to its more recent version of the Brain-in-a-vat due to Putnam. In continental philosophy, from the second half of the twentieth century, the fictional genre is the dominant kind of TE-like items to which philosophers refer; Sartre uses a sophisticated fictional scenario in his “The Wall” in order to defend a strongly Kantian condemnation of lying, even to save a life, Heidegger uses poetry and Van Gogh’s painting, and Žižek appeals to recent movies.   

The cognitive aim of coming to know and to understand can be, and often is present there, but the requirements of strictness are weaker than in TEs. In science and philosophy the TE should have a clear and univocal goal, and the proposal that is tested by it has to be decided in a non-ambiguous way. In a literary work ambiguity is often praised as a goal. Take Ursula K. Le Guin’s 1974 novel The Dispossessed - an Ambiguous Utopia, when fiction is used to create a mega TE, an interesting contrast emerges, not exactly between fiction and non-fiction, but between unambiguous-and-guided versus ambiguous, open textured imaginative exercise. The anarchist utopian planet is full of normative puzzles, like tough limitations of freedom in the interest of equality and the like; other planets seem easier to live on, but deeply unjust in many respects.

The next species concerns motivational works, utopias and dystopias. They are very similar to political TEs, say, Plato’s Republic, but their main role is a motivational one:  to be a producer of ideals, positive or negative (e.g. in the negative utopia), that should prompt action in a relatively direct fashion. Once the demand for implementation becomes central, the exercise of political imagination might become a motivational and applied one; most often it moves in the direction of positive or negative utopia. Of course, the same text is sometimes read as more epistemic, or more motivational. The epistemic/motivational contrast is important because of different functional roles of the scenarios imagined, and their consequences. For instance, being unrealistic is not fatal for an epistemic TE and might even turn to its advantage, since the absence or realistic detail might enhance the clarity of the picture proposed. In contrast, being unrealistic is fatal, or at least seriously disabling for a motivational scenario.  A well-known and ironical example is offered by the history of communist ideal, developing from political TE (utopia), through “science” and practice, from Engels to Brezhnev so to speak, and collapsing in implementation.

The final kind we are going to mention is meditation, either of a therapeutic or of a religious kind. These exercises allow for much wider variation and topical freedom than do philosophical TEs. In therapeutic controlled meditations pluralism is expected: the subject can adapt the content to her own needs, and it is the result that counts. So, once we consider other kinds of imaginative enacting in thought, and start comparing TEs to other IETs, the former seem to belong to a real kind. 

Religious mediations, for instance the ones due to Loyola or saint Bonaventura, also leave a wide space to the reader-meditator. In the case of religious meditations, we have an interesting link to philosophy. Here are Descartes’s Meditations on First Philosophy, with the TE concerning an Evil Demon:

Accordingly, I will suppose not a supremely good God, the source of truth, but rather an evil genius, supremely powerful and clever, who has directed his entire effort at deceiving me. I will regard the heavens, the air, the earth, colors, shapes, sounds, and all external things as nothing but the bedeviling hoaxes of my dreams, with which he lays snares for my credulity. I will regard myself as not having hands, or eyes, or flesh, or blood, or any senses, but as nevertheless falsely believing that I possess all these things. (2006:12)

And then comes the analogy with real meditations:

I will remain resolute and steadfast in this meditation, (manebo obstinate in hac meditatione defixus), and even if it is not within my power to know anything true, it certainly is within my power to take care resolutely to withhold my assent to what is false, lest this deceiver, however powerful, however clever he may be, have any effect on me. But this undertaking is arduous, and a certain laziness brings me back to my customary way of living (2006, p.23).

We thus have several kinds of imaginative activity close to thought experimenting, and others might be in the offing. Obviously, TEs are a species of a more general genus that encompasses examples from fiction, from linguistics, from political utopianism and from meditative activities. We have called this wider genus, or family, “imaginative exercises in thought”, IETs for short. Here is the summary of what we have been discussing:


Of course, this is just the first shot at characterizing the genus; a lot more is to be done, and both epistemology of TEs and epistemology and psychology of imagination are highly relevant for the task.

[1] See, for instance, the paper by Roy Sorensen on thought experiments and imagination in Kind 2016 and the paper by Tim Williamson in Kind and Kung 2016, 113-121;


[2] See the chapter on “Art and Thought Experiments” by David Davies in Stuart et al (2018). Catherine Elgin (in her 2007 paper) takes a similar route.


Davies, D. 2018 “Art and Thought Experiments” in Stuart, M, Fehige, Y. and Brown J.R. eds. 512-525.

Descartes, R. 2006, Meditations, Objections, and Replies, Edited and Translated by Roger Ariew and Donald Cress, Cambridge: Hackett Publishing Company, Inc.Indianapolis.

Elgin, C. Z. 2007. “The laboratory of the mind,” in A Sense of the World: Essays on Fiction, Narrative, and Knowledge, edited by Huerner W., Gibson, J. and. Pocci, L. London: Routledge.

Gendler T.S. 2004, Thought Experiments Rethought—and Reperceived”, Philosophy of Science, 71 (December) 1152–1163.

Kind, A. (ed.), (2016), The Routledge Handbook of Philosophy of Imagination, Routledge.

Mach, E. 1976, Knowledge and Error. Dordrecht, Reidel.

Sorensen, R. (2016) Thought experiment and imagination Amy Kind (ed.), , The Routledge Handbook of Philosophy of Imagination, Routledge, 420-435.

Stuart, M, Fehige, Y. and Brown J.R. eds. 2018. Routledge Companion to Thought Experiments. London: Routledge.

Vitz, R. 2015, Reforming the Art of Living-Nature, Virtue, and Religion in Descartes’s Epistemology. New York: Springer.

Tim Williamson ( 2016), Knowing by imagining, in  Kind, A. and Kung, P. (eds.)  Knowledge through imagination, Oxford University Press, 113-121;