In chemistry, the concept of a phase change refers to the transition between different states of matter, like ice melting into water, or water boiling into steam:
I believe that the same principle applies to startups and entrepreneurial careers. Success comes from phase changes--truly discontinuous shifts--rather than simple incremental improvements.
One such phase change is starting your first company. Once a founder, always a founder. Even if your startup fails, you're a member of an elite club of people who dare to swing for the fences.
Another such phase change is raising outside capital. Raising angel or VC money changes the dynamics of your company--and not always for the better. But this is generally a permanent shift--you don't raise VC, then go back to bootstrapping.
The implication of the phase change principle for entrepreneurs is that you need to focus your attention on truly discontinuous shifts--what my friend Ben Casnocha would call "breakthrough opportunities."
Transitioning from one state of matter to another requires tremendous energy, and truly changes everything. But you need to make that transition if you want to achieve success.