The phrase "concrete world" is correct and usable in written English.
It is commonly used to refer to the physical, tangible aspects of the world, as opposed to abstract or theoretical concepts. Example: In order to understand gravity, we must first observe its effects in the concrete world, such as dropping objects and measuring their acceleration towards the ground.
It's a Concrete World After All! What's the difference between cement and concrete?
They bridge the abstract world of digital computers with the concrete world of physical experience.
The concrete world of briefings and debates is an illusion, so why dwell on it?
BERLIN — The massive concrete World War II relic known as the Bunker is on many guidebooks' must-see lists.
Simulation is often presented as an alternative to symbolic reasoning, since it operates on a concrete world state rather than on first-order, symbolic representations.
For some, the ubiquity of maps – the way they are seeping into every corner of our "real", concrete world – triggers more nebulous, philosophical worries.
Lewis holds that, in addition to the world we live in, there are many other concrete worlds of the same kind as the world we live in.
This allows island universes to be possible (as they will just comprise multiple concrete worlds) without there being a world at which any island universes exist.
As noted already, Lewis (1973, 86) originally identified his concrete worlds with "ways things could have been" and realized later that the identification was vacuous.
Rather, given any intuitive possibility, it simply follows from the stipulated completeness of Lewis's account that the concrete worlds required for its truth condition exist; Recombination, in turn, expresses the richness of the worlds whose existence follows from those concrete worlds in virtue of the plenitude of logical space.
In Lewis's theory of modality, then, modal operators are understood semantically to be quantifiers over concrete worlds, predicates denote intensions understood as sets of (n-tuples of) parts of those worlds, and sentences involving de re modalities are understood in terms of counterparts.
