Envy. He was envious and never suppressed it; instead, he embraced this natural (and inescapable) feeling and thereby grew as a man.
He had just started to walk the Earth when he looked up to the sky and witnessed the birds floating within it—easily swinging in every direction. He desired the weightless lives of these free creatures and wished to be in their place. The laws of nature denied him this privilege but offered him a much more powerful form of flight: the flight of thoughts. Soon enough, his intellect guided him to the deeps of the universe—his own universe at the very least. And although he knew how to swim, he continued to drown in this unfathomable ocean. Why? He lacked self-definition, and he could not understand his very existence.
Regardless of his identity, he had but one goal; a driving force in his life. That, of course, was his lust for a life that transcends his natural limitations. After all, why should he settle for manhood (when he can exceed it as to be a unicorn)?
He foresaw the transition of his dreams into reality when he understood the reason for which objects accelerate toward the ground. He then used principles of momentum and impulse to explain changes in motion and its dynamics. Law after law—he had entered an everlasting journey of discoveries. He was a theorist and an experimentalist. His pace was not synchronized in the two fields, and his theories were much ahead. He was nevertheless confident; he believed in his derivations. He knew that eventually, he would take each of his ideas off paper and make practical use of them. And it did not take long for him to rise off the ground and employ the bird-like attributes—something he had passionately endeavoured.
He knows that the universe was not made for him and its presence is independent of his existence. He knows that there is not a hierarchy that places him in a position superior to other species. What, then, separates him from the rest of the universe? The answer is simple: he uses all components of the universe—visible, invisible, tangible, and intangible—for his own advancements. The world around him is a blueprint for his inventions. He becomes the animal he admires; he overcomes the natural forces that restrict him; he becomes the universe itself.