WHAT IS IT LIKE TO BE A BAT?

What is it like to be a bat?



What is it like to be a bat?

Introduction

Everyone knows that Thomas Nagel's famous essay "What is it like to be a bat?" is all about gaps in the philosophy of mind. It is now commonplace to distinguish carefully between an explanatory gap, and an ontological gap. An explanatory gap obtains just in case one set of concepts cannot be reduced to another set of concepts, whether by analytical definition, or by some weaker kind of reduction such as necessary coextension. By contrast, an ontological gap obtains just in case one set of properties or facts cannot be reduced to another set of properties or facts, whether by identity, or by some weaker kind of reduction such as necessary equivalence or logical (strong) supervenience.

An explanatory gap is consistent with, but does not automatically entail, the existence of an ontological gap. It is also possible to assert the existence of an explanatory gap, and remain agnostic about the existence of an ontological gap. And although this option was not so obvious when "What is it like to be a bat?" first appeared, it is now clear that this is Nagel's thesis. What very few seem to have noticed, however, is that he actually discloses two explanatory gaps in the philosophy of mind, and not just one.

Analysis

First and foremost, there is Nagel's well-known explanatory gap between mentalistic concepts and physicalistic concepts. Mentalistic concepts are concepts whose content and ascription imply phenomenal consciousness, subjective experience, or the first-person point of view: in Nagel's terms, what it is like to be for an organism. Physicalistic concepts by contrast are concepts whose content and ascription imply only first- or second-order physical properties or facts, the objective character of the natural world, or the third-person/impersonal point of view: what it is for something to be fundamentally physical. Nagel's claim here is that physicalistic or third-person/impersonal concepts can never adequately explain the subjective character of conscious experience. Let us call this "the mental-physical gap (Thomas Nagel, 1974)."

But second, for Nagel there is also a seemingly equally intractable explanatory gap between the mentalistic concepts that we apply to animals such as ourselves, and the mentalistic concepts that we apply to the conscious states of other kinds of animals. Nagel's claim here is that we are incapable of understanding the specifically subjective character of the conscious experience of other species (Paul, 1985).

In other words, for Nagel the mental-mental gap is supposed to entail the mental-physical gap. Now I do not know whether I am the only one who has ever felt a little queasy about this step in Nagel's argument. But in any case it has always seemed to me that although the mental-mental gap is perfectly consistent with the mental-physical gap, nevertheless the two gaps are in fact logically independent of one another (Hilary Putnam, 1975).

On the one hand, it is possible to hold that we cannot understand the specifically subjective character ...