From A Conflict of Visions: Ideological Origins of Political Struggles, by Thomas Sowell, page 9.

Constrained and Unconstrained Visions.

At the core of every moral code there is a picture of human nature, a map of the universe, and a version of history. To human nature (of the sort conceived), in a universe (of the kind imagined), after a history (so understood), the rules of the code apply. -Walter Lippmann 1  

Social visions differ in their basic conceptions of the nature of man. A creature from another galaxy who sought information about human beings from reading William Godwin’s Enquiry Concerning Political Justice in 1793 would hardly recognize man, as he appears there, as the same being who was described in The Federalist Papers just five years earlier. The contrast would be only slightly less if he compared man as he appeared in Thomas Paine and in Edmund Burke, or today in John Kenneth Galbraith and in Friedrich A. Hayek. Even the speculative pre-history of man as a wild creature in nature differs drastically between the free, innocent being conceived by Jean-Jacques Rousseau and the brutal participant in the bloody war of each against all conceived by Thomas Hobbes.

The capacities and limitations of man are implicitly seen in radically different terms by those whose explicit philosophical, political, or social theories are built on different visions. Man’s moral and mental natures are seen so differently that their respective concepts of knowledge and of institutions necessarily differ as well. Social causation itself is conceived differently, both as to mechanics and results. Time and its ancillary phenomena—traditions, contracts, economic speculation, for example—are also viewed quite differently in theories based on different visions. The abstractions which are part of all theories tend to be viewed as more real by followers of some visions than by followers of opposing visions. Finally, those who believe in some visions view themselves in a very different moral role from the way that followers of other visions view themselves. The ramifications of these conflicting visions extend into economic, judicial, military, philosophical, and political decisions.

Rather than attempt the impossible task of following all these ramifications in each of the myriad of social visions, the discussion here will group these visions into two broad categories—the constrained vision and the unconstrained vision. These will be abstractions of convenience, recognizing that there are degrees in both visions, that a continuum has been dichotomized, that in the real world there are often elements of each inconsistently grafted on to the other, and innumerable combinations and permutations. With all these caveats, it is now possible to turn to an outline of the two visions, and specifics on the nature of man, the nature of knowledge, and the nature of social processes, as seen in constrained and unconstrained visions.

The Constrained Vision

The Unconstrained Vision

Trade-Offs Versus Solutions

Social Morality and Social Causation

Summary and Implications