The idea that humans are autonomous individuals with individual self-interests that mutually conflict was already an old idea when it became the underlying philosophy behind the Declaration of Independence in 1776. Libertarians take this perspective as the only truth, and social philosophers such as Ayn Rand, Paul Samuelson and Ludwig von Mises are not afraid to carry the premise of individuality to its absurd logical end.
The essence of modern Western political economy is that humans are inherently selfish and that a system of rewards and punishments forcibly imposed by a strong government is all that stands between us and destroying one another for profit.
In making this postulate explicit, we can begin to examine and question it, perhaps for the first time. Compare it to the Confucian and Daoist philosophies that have been the basis of Chinese governance for 2500 years. Compare it, indeed, to the picture that modern social psychological science has painted of human nature.
In Hindu and Chinese and Inuit and all the indigenous cultures with which I have a passing familiarity, the concept of "who I am" is much more closely tied to a social context than in the modern, industrial West. I am my role in my family. I am a member of my community. I am defined by my relationships of love and work and play, the ideas I exchange, the art we create together. It's hard to imagine what I would care about, what I would do if I lived in isolation. Baby primates, including humans, die promptly if they are not held and cuddled. People in solitary confinement go mad, or worse. Older people warehoused in nursing homes die within months.
Contrast the Social Contract of Hobbes, Locke and Rousseau with the Confucian ideal which has threaded through millennia of Chinese society. To the Western philosophers, society exists as a deal made by individuals, submitting to constraints on their freedom in exchange for the means of security and comfort that are difficult for an individual to engineer on his own. To the Confucians, there is the harmony of being together and the symbiosis of a smoothly-functioning community, and from these flow the fulfillment and self-satisfaction of individual members.
There is a great deal of research supporting the Eastern view over the Western. People have mirror neurons, and they experience pain and pleasure in sympathy with those around them. Health and longevity are tied far more tightly to family relations and position in the community than to diet, self-care, genetics, or any medical variable. There are cultures where most people are happy and satisfied with life, regardless of their pecuniary circumstances, and other cultures where even the wealthiest and most powerful are chronically nervous, bitter and unsatisfied.
More controversially, there is a suppressed literature of PSI research which shows that our thoughts and motivations are not just ours individually, but can be shared and transmitted by extrasensory means that science has yet to understand.