Democracy is not rational. It has nothing to do with rationality, and everything to do with power. Democracy is concerned with the relative allocation of power and the relationship between those exercising power, and those having power exercise upon them. Democracy is concerned with matching the responsibility for power with the consequences resulting from the exercise of that power, and providing a system for the dynamic re-allocation of power in response to shifts resulting from the previous exercise of power.
With democracy, it is never a question if a solution is the BEST solution, but rather a question if the solution is politically acceptable. What rationality each voting person within a democracy uses to achieve their understanding of what is the best solution does not matter.
The rational-perfect, scientist-expert, scientific management, social sciences perspective of government is not a product of the Enlightenment era. The central premise of the Enlightenment era was the call to “Have the courage to use your own reason”. The central thesis of the Enlightenment era is that the personal exercise of ones own wisdom was better then the quiet acceptance of revealed truth about the world and the patterns of relationships within it. To an enlightenment thinker, the premise was “It is not necessarily as they say”.
This independence allowed philosophers to challenge “revealed truth” of the rules controlling natural and social systems by revealing logical and empirical inconsistencies within it. Thus, enlightenment thought made it possible to challenge both established political structures (by elaborating a possible competing political structure) and accepted “laws” governing nature and medicine.
While it is true that natural philosophers began to apply the method of rational and empirical enquiry to the natural world during the Enlightenment era, it was several hundred years before this approach was applied (or could be applied) to the human world.
It was later, during what I shall term the “Progressive era”, that the question of what uses the democratic political power of the (still small) minority of voters should be applied.
The Progressive Era was based upon the foundation that it was possible and good for the powers of governance (whether civic or corporate) to improve the overall quality of life for people, both individually and collectively, by using the power of governance to improve individuals and communities.
The ‘gheist’, or Spirit of the Era of the Progressive era was based upon an ethical decision, while the gheist of the Enlightenment era was founded upon an epistemological issue.
The gheist of the Progressive Era was made possible by certain patterns of thought and technologies which did not exist within the Enlightenment age. The idea of governance by technical rationality flowered only once it became possible to apply scientific methodology to complex activities.
This was made possible only with the advent of three things: Sufficient standardization of information to allow for collation, a population sufficiently literate to supply the amount of specialty labor necessary to make data collection transferal, analysis, and communication possible, and a conceptual understanding of “populations”.
While categorization was conceptual technique readily available to natural philosophers during the enlightenment era, the concept of a “population”, of a grouping of similar things within a category sharing an assortment of measurable dissimilar traits, was not.
To treat populations as things that could be quantifiably described by any method other then the most basic of numbering was not something that arose until the advent of industrial capitalism and interchangeable parts created sufficient “sameness” in populations of material things that the same concept of treating populations of people as interchangeable parts arose.
Thus, it is impossible to say that “rationality” is a fundamental characteristic of democracy. The addition of explicit rationality to the process of democracy was an attempt to answer the ethical question of “to what uses shall the power of governance be put?”, and how power should be exercised upon the “public” part of the population, which lacked decision power. Rationality in democracy was an attempt by a sub-set of the population to determine what exercise of power would better the rest of the population. That the methodology established to do so happen to be a rational-scientific model has nothing to do with the fundamental underpinnings of democracy.