Someone might say, in response to my talk (in the last blog post) of 'having an idea in the shower', that my idea was not literally in the shower.
This is either a mistake or not even a mistake.
My saying that it is a mistake is not my claiming that it is straightforwardly apt to say that my idea was in the shower.
What however is straightforwardly apt to say is that I had an idea in the shower.
I actually had this idea in the shower. It was actually in the shower that I had this idea.
The truth is it is unclear what is meant by saying of an idea simpliciter that it is or is not in the shower. I don't really know, unless I or you or we first stipulate to specify, what it would mean to say of an idea that it is or isn't in the shower.
It is therefore not straightforwardly either literally or metaphorically true or false to say of it that it is in the shower.
One thing we could mean by talk of an idea being in the shower is that this is where it was had. If this is what we mean by saying that the idea was in the shower, then it is literally true that the idea was in the shower.
We do not rightly use the word 'literally' to mean: conforming to grammatical paradigms appropriate to statements about (our knowledge of) the form and spatial and temporal location of physical objects.
Thus 'in' does not always mean 'inside'; 'have' does not always mean 'possess'. There are different non-metaphorical uses of these terms.
We could use the word 'metaphor' in a metaphorical sense - as do Lakoff and Johnson. They use it to mean: deviating from physical paradigms. That's fine, so long as we acknowledge what we're doing.
What is true of someone if they have an idea in the shower is different in character from what is true if someone's cat climbs in the shower with them or if there's a new bar of soap in the shower. It is not true in that sense.
But it is no more true to say that I did not literally have a cat or a good time of it or some new soap in the shower (because of not having them in the shower in the same kind of a way that my idea was had in the shower) than it is to say that I did not literally have an idea in the shower (because I do not have ideas in the shower in the same sense in which I sometimes have cats (well, just imagine it, ok) or good times of it or new soap bars in the shower).
We are not forced to individuate senses using only a literal / metaphorical distinction.
And what do we say to someone who tells us that whilst the idea was not in my shower it was in my brain?
Well, I might wonder if they meant, by 'in my brain': 'in my mind'. For to have had an idea in mind is, roughly, to be thinking on something but not yet to have said it. And maybe 'brain' is here a metaphor for 'mind'?
'Well no', they say, 'I don't mean in that sense of 'in your brain'. Yet I do mean that it is in your brain as a matter of fact.'
And that's fine with me, if you don't mean it in that sense. But please tell me now: just what sense is it you have in mind when you say that it is literally in my brain? ... Really, I'm all ears (metaphorically speaking).
After all, not everything I have (a sweet temperament, a good view, a PhD) is in something or other.