idealism

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or practice of envisioning things in an ideal and often impractical form.
• noun Pursuit of one's ideals, often without regard to practical ends.
• noun Idealized treatment of a subject in literature or art.
• noun Philosophy The theory that the object of external perception, in itself or as perceived, consists of ideas.

from The Century Dictionary.

• noun The metaphysical doctrine that the real is of the nature of thought; the doctrine that all reality is in its nature psychical.
• noun Pursuit of the ideal; the act or practice of idealizing; especially, imaginative treatment of subjects; a striving after ideal beauty, truth, justice, etc.
• noun In art, the effort to realize the highest type of any natural object by eliminating all its imperfect elements and combining the perfect into a whole which represents Nature, not as she is exhibited in any one example, but as she might be.

from the GNU version of the Collaborative International Dictionary of English.

• noun The quality or state of being ideal.
• noun Conception of the ideal; imagery.
• noun (Philos.) The system or theory that denies the existence of material bodies, and teaches that we have no rational grounds to believe in the reality of anything but ideas and their relations.
• noun The practice or habit of giving or attributing ideal form or character to things; treatment of things in art or literature according to ideal standards or patterns; -- opposed to realism.
• noun a belief in the feasibility of the implementation of ideal principles and noble goals, and the practice or habit of pursuing such goals; -- opposed to realism and cynicism.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The property of a person of having high ideals that are usually unrealizable or at odds with practical life.
• noun philosophy An approach to philosophical enquiry which asserts that direct and immediate knowledge can only be had of ideas or mental pictures.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun (philosophy) the philosophical theory that ideas are the only reality
• noun impracticality by virtue of thinking of things in their ideal form rather than as they really are
• noun elevated ideals or conduct; the quality of believing that ideals should be pursued