Tortoises, and How to Respond to Them - a Field Guide

"...[C]onditions which often look alike/Yet differ completely, flourish in the same hedgerow..." (Eliot, "Little Gidding," III).

I.Tortoises
As proposed in the previous post, the Tortoise is someone who, like The Tortoise in the Lewis Carroll fable, demands an explanation of something that, for structural reasons, does not admit of explanation. Some examples of 'structurally inexplicable' things include modus ponens in classical logic, the justification of inductive generalizations, whether external world skepticism is true, and why there is something rather than nothing.

Related predicaments ensue, as Peter Railton points out in "How to Engage Reason," whenever an extra step seems needed to explain the transition from one thing to another--e.g. from a belief and desire judgment to an action (or perhaps an intention). Although an action is not a fundament of a system of reasoning, it is irreducible. There is a transition one must make or not make, and no volume of rational support will make it for you.

Tortoise-inviting transitions are similar to those that invite the Paradox of Analysis, but not identical. The Paradox of Analysis arises when a concept cannot be fully captured in an analysis of its meaning in other terms. But a transition, like those listed above, is not a concept, but a relationship between a basis and a conclusion. In both cases, something goes uncaptured, but in tortoisean cases what is not captured, or rather 'secured,' is that one will accept reasoning performed correctly using a given basing relation. (I want to distinguish between the two because The Paradox of Analysis can arise with any concept one attempts to analyze, whereas difficulty seeing why something follows from something else is less prolific.)

One may also ask tortoisean questions about something that is seems to basic to admit of explanation without reference to a particular system of explanation, if it seems none suits the phenomenon. In a way, what one is doing in such a case is turning the mysterious thing--e.g. how basic actions are possible--into something the transition to which needs explaining in the way the transition from (A, (A-->B)) to B does (to a Tortoise). One takes a position from 'below' the thing, and asks how it ever occurs. Yet the answer the Tortoise wants will have to both take into account how it seems to the Tortoise when it happens, and provide an explanation from 'below.' The ideal explanation will cover the movement from one side of the transition to the other without leaving any gaps into which doubt can be inserted. Some examples include: basic actions, action following from practical reasoning, committing oneself to some goal, thinking, imagining, believing, desiring, and having experience as of objects in the world.

II. Ways of Responding to a Tortoise

( The Rundown )