“Information wants to be free.”
--Stewart Brand.
Ideas are powerful things. Because they do not inhabit an abstract realm, we can interact with them. This interaction, of course, is the province of the mind rather than the body, as the idea is abstract; only the ideas' manifestations are physically tangible. As we use a variety of hand movements, such as grasping and poking, to interact with objects, we use a variety of mental “tools” to interact with ideas. Chief among these tools is language, for it is the primary medium in which ideas may be passed from one person to another, easily making it the most important invention humanity has ever devised. Other tools, such as intuition and logic, are innate mental processes bestowed upon us sometime in the course of our evolution. Of such solitary generative tools, intuition is likely the most important, as it is capable of perceiving and synthesizing nonlinear relationships between ideas (unlike logic, which is a strictly linear tool, lends itself primarily to A→B ^ B→C ⇒ A→C sort of thinking), but is the most difficult to control, being a primarily subconscious or “irrational” trait (in the Jungian sense).
Occasionally, our innate methods touch directly upon the idea itself; we usually term such contact creativity, as the idea seems to spring from nowhere, but more often, we perceive ideas through their representations. For example, we may discover the theme underlying a story in the process of reading it, or we may note the emotions put into a piece of art or music while experiencing it. Society tends to call the latter ability “appreciation”, although that name does not capture the full nature of the communication that takes place.
We tend to call individuals who perceive and realize many of their own ideas creative. As intuition is the primary tool used to discover new ideas, it is often very difficult even for creative individuals themselves to explain how they came up with an idea (and it is not uncommon for them to consciously look back on the finished work later and think “how did I do that?”, as their primary operation while creating was subconscious). Much of the key to creativity thus lies in creating a “receptive environment” conducive to the intuition discovering new ideas rather than attempting to rigorously wring forth ideas through a conscious effort of will. Some keys to doing so are recording ideas as they occur, withholding immediate attempts to judge one's own ideas (the downfall of most scientists who get in the habit of discarding their hypotheses too quickly), surrounding yourself with a physical environment in which you feel relaxed, and taking periodic breaks (walking is an excellent activity). Gathering as much breadth as possible is also vital, as new ideas are frequently perceived as combinations of other simpler ideas. Thus, the more disparate knowledge one possesses, the more likely it is that one will be able to generate new ideas by fusing ideas already in one's knowledge-base.
Something very puzzling happens to creative individuals, particularly in the arts: the ideas seem to take on a compulsive force, and the realization of, say, the theme of a piece of music, frequently becomes an urgent desire that can nevertheless not always be met quickly. This can cause considerable frustration as the details of realization slow down or halt the expression of the idea, and frequently sets the realm of ideas against more prosaic things for such creative individuals. Most creators seem to enjoy what they do enough to counter this frustration while working, but it can potentially leave them out of touch with reality at times.