Questions for the Audience, and For Readers

In a somewhat novel twist, at one point O'Rourke interrupted the question-and-answer session in order to pose questions to the audience. I'll pose them to you.

1. It's easy to think of examples of metaphors where a word for something perceptible is used to talk about something ostensibly imperceptible. But are there any metaphors where a word for some imperceptible thing is used to talk about some other imperceptible thing? (Construe 'perceptible' broadly, so that, for instance, the sequence of time in a day, already mentioned, counts as perceptible.)

2. There seems to be an aspect of 'impropriety' (as it is called) in a metaphor, because a metaphor implies the transfer of a term from its proper domain to some domain in which it does not belong. (The proper domain is that in which the term is used 'strictly' or 'literally', kuriws.) What licenses the transfer, despite the impropriety, is some action or function of what we wish to talk about (or so O'Rourke wished to claim). Or is this not true--Can one think of some metaphorical use of term, where the metaphor is not underwritten by the action or function of what one wants to talk about?

3. A similarity of relations is an analogy, e.g. cup:Dionysus::shield:Ares. But should an identity of relations also be counted as an analogy, e.g. 2:4::3:6 ? And, if so, would it license a metaphor? What would be an example of this?