1) Knowledge means falsifiability. The purpose of scientific knowledge is to make testable predictions about observable phenomena. Any belief that does not do this is not scientific and has no place in a fact based discussion.
For example, the belief that Buddhism is the most beautiful religion is in exactly the same category as the belief that Sean Connery is the best James Bond.
2) Humans are fundamentally flawed. Not only are we evil, we are also stupid. The human brain is subject to a wide variety of cognitive flaws. Because of this, almost all of the output the human brain produces has no value in determining the truth about reality. The scientific method is the only known, reliable way of finding knowledge.
3) Because of human flaws, life in a state of nature is nasty, brutish, and short. Even if we lived in a paradise and all of the natural problems of disease and parasites and predators and malnutrition were somehow waved away, we would turn it into Hell by inflicting violence on each other. Observe the historical behavior of all human beings before civilization.
4) The reason we do not currently live in a state of nature is our institutions: rule of law, individual freedom, democracy, the scientific method, private property, free markets. It is theoretically possible that better institutions exist, but we have never observed any desirable and well functioning society that lacks these institutions.
Note: When I use words like better and worse, good and bad, or make any other normative statements, I am referring to the revealed preferences of large numbers of human beings. A better society is one that people choose to move to.
5) Good institutions do not occur easily. They were developed by trial and error over millenia. Revolutionary change has the potential to threaten these institutions. Theories and philosophies have been shown to be incredibly bad at designing institutions. However, some of our most important institutions were developed as a result of revolutionary experimentation. We can and should improve our institutions with gradual change and local experimentation.
6) Instinctive human morality is a set of behavior patterns that evolved to coordinate the activities of tribes of foragers in a Paleolithic environment. It is not sufficient to create institutions that function well in a modern world, and in some cases it works against good institutions. For example, the inherent repugnance toward dissecting human bodies caused medical progress to be slower and resulted in millions of lives being lost and a great deal of unnecessary suffering.
7) Social facts, and especially economic facts, are rarely the result of human intention or desire. They are the result of complicated impersonal forces that are best understood through rigorous study and the scientific method. Attempting to alter social or economic conditions without the knowledge that came through such careful study is likely to be counterproductive and possibly disastrous.