The relationship between abstractions and concretes, or concepts and reality, is discussed at length in Ayn Rand's monograph, Introduction to Objectivist Epistemology, which I highly recommend for making any sense of what I'm about to type...
Basically, this comes down to being clear on the distinction between the "what" and the "how" in awareness -- the object of awareness, in contrast to the form which that awareness takes. Concepts are a way of regarding things, a certain kind of abstract perspective on concretes that stems from the natures of the concretes involved (and the nature of our minds). That is, we humans enjoy a conceptual form of awareness.
So concepts and abstractions certainly exist as an objective, reality-based form of awareness, but they do not have any existence independent of the mind that is using them.
A concept is essentially the same thing as an abstraction.
Concepts (abstractions) are a result of an act of consciousness called conceptualization (or abstraction). A new concept is a new aspect of one's consciousness.
The concept is of a type of thing you might be aware of.
For instance, once you conceptualize tables as such, your are said to have a concept of "table". The concept exists, not as a physical thing, but as a new aspect of your mind which enables you to deal with tables more effectively throughout your life.
Given the concept, you have a foundation for learning all kinds of additional things about tables as such, e.g. that some are made of wood, that some can be folded up, that surgeons perform operations on them, etc.
Given the concept, you are also able to recognize tables you might come across -- tables which might look very different from any table you've seen before.
Given the concept, you can think about tables, e.g. how you might make a better one than the one you already have.
And, of course, having a concept of "table" allows you to write and speak about tables.
All these things about concepts make them very real, if not physical, things.
answered Oct 21 '10 at 19:12
John Paquette ♦