I don't see it as expansion or shrinkage but more of different connections of brain cells. Especially with specific substances we create pathways in our brains that we don't normally tap in to which causes new idea a to form.

You don't have profound thoughts, you just think that you do. My dad used to tell a story about a mathematician he knew who did some psychedelics and wrote down his profound thoughts only to wake up to gibberish.

Maybe you're having the most profound thoughts, but maybe you're also raising those points with the cat or ficus tree and maybe it's all gone once the stupor's over

I can say that as a songwriter I have ideas about songs, or even just random dreams while I'm going to bed, and then after I wake up they're gone. I can't remember a damn thing about them. It even happens when I'm awake sometimes. I'll have an idea and then I'll do even just the simplest thing instead of sticking to what I'm thinking about and then the idea is gone. It's like the idea slips into a void or something. That's why they tell you that you should write an idea down immediately or record it right away. I don't know if they're profound ideas or songs, and they aren't drug induced, but they happen. There is some place we "go" that seems to be that state in between sleep and awareness where we can think of wonderful things, but not remember them when we come back to "reality". WTF? Lol

I get this when lying down. Not easy to write when you're completely horizontal, and I've tried a tape recorder, but then my brain freezes. Awful predicament.

I think better when I'm relaxed. I mean I think better philosophically. I don't drive better drunk. But not just philosophically. When I was in college, doing very non-philosophical stuff like spreadsheets and annual rates of return, being somewhat drunk really helped open my mind to tricky questions.

Look at almost any famous musician. Just saying...

I quit drinking over 7 years ago. My brain is clear and every day I come up with wild stuff. Was listing to the radio earlier. I would swear the singer said titty tantrum.

Look my wonderful friends....I am so pissed right now ....wow awesome...lol

It's debatable, But I know that a lot of great music has been written by those that were either High, or drunk.
That's even going back to many Classical composers.

Go Ask Alice.

In my opinion, anything induced by consciousness altering chemicals is nothing more that alt-reality and has nothing what-so-ever to do with reality.