By speaker > Oliver Robert

The epistemology of modality is a branch of epistemology that addresses how we are justified in believing what is possible or necessary for objects and propositions. The main questions that structure the debate are the so-called access and navigation questions (Vaidya and Wallner 2021): First, how can we epistemically access the modal realm? Second, how can we navigate from one kind of modality to another? In this paper, I will focus on the former. More specifically, I will defend that there is an easy and early way for us to access negative modality, i.e., knowledge of more or less constrained impossibilities, such as “it is not possible that A” (¬◊A) or the equivalent “it is necessary that not-A” (□¬A), based on our own inabilities.

I will do this within an anti-exceptionalist and empiricist framework, which asserts both that our modal knowledge has the same regular sources from which we obtain non-modal knowledge about the world (Williamson 2007; Vetter 2016, 2023), and that our knowledge of modality is mainly a posteriori, given that experience plays a large justificatory role (see Fischer and Leon 2017). My account is also agency-based, as it finds a starting point for modal thinking and knowledge in the experience of our own agency (Vetter 2023, 2024).

I will argue that our own inabilities constitute early and easy access to modal knowledge. Agentive modal knowledge concerns our own abilities and inabilities, as well as objects' affordances ‒ roughly, affordances are the conjunction of an agent's abilities and certain properties of an object that constitute an opportunity for the agent to act on or interact with this object, e.g., a book being such that it can be read by a literate human but not by an ape. But is there a common source for all types of agentive modal knowledge? First, I will examine whether the main empiricist theories of modal knowledge can explain knowledge of abilities, inabilities, and affordances by appealing to a common source. The answer, if I am correct, is that they cannot. I will then focus on explaining the main sources for a subset of agentive modality: negative agentive modal knowledge, i.e., knowledge of inabilities and of what objects do not afford. Knowledge of ability, and especially of inability, is underexplored, apart from a few exceptions (Vetter 2023, 2024).

How are we to explain knowledge of inabilities? Does knowledge of our own inabilities have the same source as knowledge of others' inabilities? Or does inability belief require the same kind of warrant or justification as ability belief? We have knowledge of at least some of our own inabilities ‒ e.g., I cannot fly ‒ without even attempting to φ. Knowledge of some inabilities might emerge very early, perhaps earlier than knowledge of closely related abilities. From an evolutionary perspective, survival seems to require easy knowledge of inabilities not acquired through testing.

I will present a novel account of negative agentive modality, identifying knowledge of inabilities as one of the roots or starting points for modal knowledge and explaining what makes an agent's true beliefs about what they are not able to do warranted or justified. I will argue that imagination (see Kind and Kung 2016 and Hanrahan 2021), together with the perception of action-properties or affordances (Nanay 2011; Strohminger 2015; Vetter 2020), plays a key role in providing us with knowledge of our own inabilities.

Finally, I will briefly outline a way we could navigate from knowledge of inabilities to non-action-related, objective impossibilities, using standard methods of inquiry, such as inductive inference, analogical reasoning, and abduction.