The salient feature of the human experience is the dynamic process of valuation. From the philosophers of ancient Greece to the Pygmy tribes of the modern Amazon, humans have been universally faced with a scarcity of time and resources about which they must make decisions.
Man's primary end is survival and he has proven resilient among the animal species from one end of the globe to the other. While other animals live and die as a process of natural selection over which they can exert no influence, the mind of man has made him uniquely aware of his situation and capable of not just adapting to his environment but manifesting his imagination and building on top of the natural world his various civilizations.
As man conquered the limitations of mere survival, he found further unease with which to contend: a better roof, a warmer hut, a sharper spear. As man progressed from eliminating one unease to the next - in effect, as civilizations progressed - another aspect of human nature is made clear by a methodological individualist understanding of history: the unceasing and various existence of unease experienced by man. Man seems to have an infinite capacity to experience unease. As his material standard of living grows further away from mere survival, new uneases begin to manifest that affect his psyche and his spirit.
Coincident with the leisure of time afforded by capital accumulation, the various philosophies of man have been constructed in order to deal with the intangible manifestations of unease: new ends beget new means and the various systems of thought were borne.
I am going to digress for a moment. I make the points above in order to make evident the innumerable ideas which have needed to grow and evolve in order to animate the various actions of modern man. The collections of humans tentatively organized around common systems of thought from social networks to loose cultures to whole civilizations share common threads in the valuation of certain ultimate ends; but, the means to attain them are enormous and unquantifiable being that they are the subject of thought.
As people gathered together, they began to share ideas about ends and means. Those people whose experience differed greatly from others were able to pass on a priori understanding of possible future situations, probabilities and uncertainties, new ends and new means. No longer was personal experience necessary to gain understanding about the world. Ideas about what to strive for and how to strive for it were shared between humans who saw in others a common rationality and the benefits conferred by a shared system of ultimate ends.
Cultures formed first around the need to survive and grew to encompasses ideas about more metaphysical ideas like family, marriage, religion and law. I contend that these experiences formed over generations and solidified into institutions as a result of meeting highly valued ends. In a sense, one can perceive culture as a fractal composed of the experiences and valuations of individuals and settling around the most shared values. Cultures thus can be analyzed around their shared ideas.