Full Idea
Nagel's title invites us to ignore all the different ways in which bats might accomplish their cunning feats without its "being like" anything for them. We create an impenetrable mystery for ourselves if we assume that Nagel's title makes sense.
Gist of Idea
Nagel's title creates an impenetrable mystery, by ignoring a bat's ways that may not be "like" anything
Source
comment on Thomas Nagel (What is it like to be a bat? [1974]) by Daniel C. Dennett - Kinds of Minds Ch.6
Book Reference
Dennett,Daniel C.: 'Kinds of Minds' [Phoenix 1997], p.212
A Reaction
This could well be correct about bats, but the question applies to humans as well, and we can't deny that "what it is like" is a feature of some creatures' realities. On the fringes of our own consciousness there are mental events that are "like" nothing.