However, three additional points need to be made: first, libertarianism is not just these broad liberal principles. Libertarianism applies these principles fully and consistently, far more so than most modern thinkers and certainly more so than any modern government. Second, while our society remains generally based on equal rights and capitalism, every day new exceptions to those principles are carved out in Washington and in Albany, Sacramento, and Austin (not to mention London, Bonn, Tokyo, and elsewhere). Each new government directive takes a little bit of our freedom, and we should think carefully before giving up any liberty. Third, liberal society is resilient; it can withstand many burdens and continue to flourish; but it is not infinitely resilient. Those who claim to believe in liberal principles but advocate more and more confiscation of the wealth created by productive people, more and more restrictions on voluntary interaction, more and more exceptions to property rights and the rule of law, more and more transfer of power from society to state, are unwittingly engaged in the ultimately deadly undermining of civilization.
As indicated in the above chart, our more complex ideas of the imagination are further divided between two categories. Some imaginative ideas represent flights of the fancy, such as the idea of a golden mountain; however, other imaginative ideas represent solid reasoning, such as predicting the trajectory of a thrown ball. The fanciful ideas are derived from the faculty of the fancy , and are the source of fantasies, superstitions, and bad philosophy. By contrast, sound ideas are derived from the faculty of the understanding— or reason—and are of two types: (1) involving relations of ideas; or (2) involving matters of fact. A relation of ideas (or relation between ideas) is a mathematical relation that is “discoverable by the mere operation of thought, without dependence on what is anywhere existent in the universe,” such as the mathematical statement “the square of the hypotenuse is equal to the square of the two sides” ( Enquiry , 4). By contrast, a matter of fact, for Hume, is any object or circumstance which has physical existence, such as “the sun will rise tomorrow”. This split between relations of ideas and matters of fact is commonly called “Hume’s Fork”, and Hume himself uses it as a radical tool for distinguishing between well-founded ideas of the understanding, and unfounded ideas of the fancy. He dramatically makes this point at the conclusion of his Enquiry :