Independence and nonconformity are usually seen as two sides of the same coin. A person who is independent does not conform to the pressures of others. A person who is nonconformist is usually viewed as having an independent streak. Contrary to this popular perception, rebelliousness and individualism are incredibly different. Admittedly, the two traits have similar outward manifestations. It is only when you can evaluate the intent, the mindset, and the purpose of the person that the difference becomes clear. Here's what I've discovered.
Rebelliousness or nonconformity can be attractive at first. Someone who rejects social norms, the Rebel, is an enticing adventure for those who seek to understand how other minds operate, those with an inquisitive nature. But, after getting to know the Rebel, we come to discover that the nonconformist attitude is quite superficial. The Rebel knows not what he rebels against. He rebels for the sake of rebelling. He decries conformity simply because he cannot understand how to express his identity within the framework provided. Put succinctly, the Rebel is a contrarian, not an individual.
In contrast, after getting to know the nonconformist, we may conclude that there is a purpose to his rebelliousness. This person, the Individual, has given hours of contemplative thought on the subject of his nonconformity. He has critically evaluated social norms and come to an objective assessment based on his own rational thought. If the conclusion he arrives at is contrary to the prevailing norm, he has a choice: (1) compromise his integrity and values by conforming, or (2) preserve his integrity and act independently from others.
The Individual know who he is, what he values, and acts accordingly--even if doing so bucks convention. The Rebel bucks convention because he does not have a sense of identity. The Rebel speaks in terms of "what he is not." The Individual speaks in terms of "what he is" and then demonstrates how that identity is different from others.
Individualism requires self-reflection, critical thought, and independence.