Resisting an invitation to suppose

Catherine Wearing is Associate Professor of Philosophy at Wellesley College. She works chiefly in philosophy of mind and philosophy of language.

Catherine Wearing is Associate Professor of Philosophy at Wellesley College. She works chiefly in philosophy of mind and philosophy of language.

A post by Catherine Wearing.

There’s some disagreement in the literature as to whether supposing and imagining are distinct activities, and if they are, what exactly distinguishes them. But one fairly widespread point of agreement is that supposing is less constrained than imagining: we can suppose things that we can’t imagine. And not only does supposing seem to be less constrained than imagining, it is often taken to be completely unconstrained. One can suppose anything, even a contradiction, if it’s for the sake of carrying out a proof by reductio ad absurdum.

The question I want to take up here is whether there are barriers to what we can suppose. More specifically, is there such a thing as ‘suppositional resistance’ (by analogy with the much-discussed phenomenon of imaginative resistance)? Imaginative resistance is just what it sounds like: a felt resistance to imagining something when asked. It typically arises when we are asked to imagine something morally repugnant or flatly impossible. To borrow a well-known example from the literature, many people balk at being asked to imagine that “in killing her baby, Giselda did the right thing; after all, it was a girl” (Walton 1994, 37). Similarly, Yablo (2002, 485) tells a story in which Sally finds the last item required for a treasure hunt – an oval – when she comes across a five-fingered maple leaf. Many people experience resistance when asked to imagine Sally finding a five-fingered oval. But if we consider these statements purely ‘for the sake of argument’, there doesn’t seem to be any particular difficulty with supposing that female infanticide is a good thing or that someone has found a five-fingered oval. It would appear, then, that while imaginative resistance is real, suppositional resistance is not.

I think the situation is not this tidy. People do sometimes have difficulty ‘merely supposing’. For example, I’ve encountered suppositional resistance while discussing reasons for and against the permissibility of abortion with people who are strongly opposed to it. In the course of the discussion, I might say, “Let’s just suppose that fetuses don’t have souls”, to which the person responds, “But they do have souls!” My attempt to introduce a purely hypothetical scenario has hit a wall. I take this to be a refusal to suppose on my interlocutor’s part: taking on board the proposition that fetuses do not have souls, even ‘just’ for the sake of argument, is somehow beyond them.

Cases like this suggest that suppositional resistance is a real phenomenon. We might then wonder whether suppositional resistance arises for the same sorts of reasons as imaginative resistance. Diagnoses of the source of imaginative resistance have fallen into two broad kinds, inability and unwillingness. As Gendler (2006) puts it, is resistance a matter of can’t or won’t? In morally repugnant cases, it is easy to see how one’s resistance might stem from an unwillingness to imagine as one is asked. In cases like the five-fingered oval, it’s plausible that the problem might derive from an inability to perform the required imaginative work: one simply can’t work out how to go about imagining what one is being asked to imagine. (To be clear, I don’t mean to endorse this tidy division of cases, only to illustrate how each explanation might go.)

So is suppositional resistance a matter of ‘can’t’ or ‘won’t’? The example I gave earlier certainly looks like a case of unwillingness. In general, suppositional resistance seems to arise when discussing a position to which one is deeply opposed, even if it’s clear that no one is endorsing the position. If that’s right, then we might expect that suppositional resistance will be a result of unwillingness. Cultivating detachment is something that improves with practice, and like many logical and analytical skills, it’s hardest to exercise when tempers are high or our deepest commitments are being challenged.

Interestingly, Tamar Gendler (even while appealing to the supposition-imagination distinction in her account of imaginative resistance) acknowledges the existence of cases of (at least mild) suppositional resistance, and the example she offers also seems to stem from unwillingness. She writes, “even though I am not engaged in a full-fledged act of imagining [when I suppose], there seems to be something unseemly about supposing for the sake of argument that the Rwandan genocide was not such a bad thing because the victims were poor…” (2006, 155). On Gendler’s account, supposition gives one distance from a hypothesis in a way that imagining does not, which makes it easier to take a challenging hypothesis on board. But even this attempt may fail. One may not be able to get enough distance; one may feel that one is committing a wrong, even by ‘merely supposing’.

Is this to say that suppositional resistance couldn’t arise from an inability, rather than an unwillingness, to suppose? It does strike me as odd to think that there is a claim that cannot be supposed by anyone under any circumstances. (Let’s set aside cases where we lack the concepts in which to formulate the supposition). Supposition is such a minimal sort of entertaining or hypothesizing. As noted earlier, we can suppose the impossible. It even seems possible to suppose when you’re not sure what the content of your supposition amounts to. You may not know what a farrier is, but it seems easy enough to obey the instruction to suppose that your grandfather’s best friend was one. On the face of it, then, suppositional resistance looks to be more plausibly the result of unwillingness.

So where does this leave us? It is true that we can suppose more than we can imagine. Perhaps we can suppose anything, if the conditions are right. But I’ve suggested that suppositional resistance, like imaginative resistance, is real – attempts to suppose sometimes founder. It would be interesting to look further into the causes of imaginative and suppositional resistance. I’ve suggested that the latter is always the result of unwillingness, but I haven’t endorsed any particular explanation of imaginative resistance here. If the inability explanation seems plausible for at least some cases of imaginative resistance, then that marks a difference between imagining and supposing. How much weight we can hang on that difference remains to be established.


Gendler, T. (2006) “Imaginative Resistance Revisited” in Nichols, S. The Architecture of the Imagination. Oxford: Oxford University Press, 149-173.

Walton, K. (1994) “Morals in Fiction and Fictional Morality” Proceedings of the Aristotelian Society, suppl. Vol. 68, 27-50.

Yablo, Stephen (2002). “Coulda, Woulda, Shoulda”, in Gendler and Hawthorne, Conceivability and Possibility. Oxford: Oxford University Press, 441-492.