what is the abstract and concrete in modern linguistics?

Answer 1

"Abstract" refers to something that you CAN'T physically see or feel (by touch or smell, for instance). "Concrete" refers to the opposite -- that is, something that you CAN physically see or feel. Ideas, for example, are abstract -- you can't see or feel them. People, animals, physical objects and the like are concrete, as you can see and/or feel them.

Answer 2

I have heard concrete used, as concrete thinking. It is a way of thinking where the person takes everything literally. That is completely impossible in real life to do, and so I believe it is actually a mental illness.

For instance, " I been to the desert on a horse with no name, in the desert you can't remember you're name." Of course you can! It has only symbolic meaning, the whole thing. A person would have to have a mental problem not to know that, I have met people like that. They drvie me nuts, not literally speaking!

Abstract thinking would be freer and much more creative. Like that song, for an example, again.
Able to understand concepts outside it's usual sphere, like understanding other cultures and religions and able to conceive they do not conflict with you're own at all at there basic roots.

Both ways of thinking have their place.