The Principle of Empiricism, or See For Yourself
Empiricism is the deepest and broadest principle for explaining the most phenomena in both the natural and social worlds. Empiricism is the principle that we should see for ourselves instead of trusting the authority of others. Empiricism is the foundation of science, as the words of the motto of the Royal Society of London—the first scientific institution—so note: Nullius in Verba—Take nobody's word for it.
Galileo took nobody's word for it. According to Aristotelian cosmology—the Catholic Church's final and indisputable authority of Truth on matters heavenly—all objects in space must be perfectly round, perfectly smooth, and revolve around Earth in perfectly circular orbits. Yet when Galileo looked for himself through his tiny tube with a refracting lens on one end and an enlarging eyepiece on the other he saw mountains on the moon, spots on the sun, phases of Venus, moons orbiting Jupiter, and a strange object around Saturn. Galileo's eminent astronomer colleague at the University of Padua, Cesare Cremonini, was so committed to Aristotelian cosmology that he refused to even look through the tube, proclaiming: "I don't believe that anyone but he saw them, and besides, looking through glasses would make me dizzy." Those who did look through Galileo's tube could not believe their eyes—literally. One of Galileo's colleagues reported that the instrument worked for terrestrial viewing but not celestial, because "I tested this instrument of Galileo's in a thousand ways, both on things here below and on those above. Below, it works wonderfully; in the sky it deceives one." A professor of mathematics at the Collegio Romano was convinced that Galileo had put the four moons of Jupiter inside the tube. Galileo was apoplectic: "As I wished to show the satellites of Jupiter to the Professors in Florence, they would see neither them nor the telescope. These people believe there is no truth to seek in nature, but only in the comparison of texts."
By looking for themselves Galileo, Kepler, Newton and others launched the Scientific Revolution, which in the Enlightenment led scholars to apply the principle of empiricism to the social as well as the natural world. The great political philosopher Thomas Hobbes, for example, fancied himself as the Galileo and William Harvey of society: "Galileus…was the first that opened to us the gate of natural philosophy universal, which is the knowledge of the nature of motion. … The science of man's body, the most profitable part of natural science, was first discovered with admirable sagacity by our countryman, Doctor Harvey. Natural philosophy is therefore but young; but civil philosophy is yet much younger, as being no older…than my own de Cive."
From the Scientific Revolution through the Enlightenment the principle of empiricism slowly but ineluctably replaced superstition, dogmatism, and religious authority. Instead of divining truth through the authority of an ancient holy book or philosophical treatise, people began to explore the book of nature for themselves.
Instead of looking at illustrations in illuminated botanical books scholars went out into nature to see what was actually growing out of the ground.
Instead of relying on the woodcuts of dissected bodies in old medical texts, physicians opened bodies themselves to see with their own eyes what was there.
Instead of burning witches after considering the spectral evidence as outlined in the Malleus Maleficarum—the authoritative book of witch hunting—jurists began to consider other forms of more reliable evidence before convicting someone of a crime.
Instead of a tiny handful of elites holding most of the political power by keeping their citizens illiterate, uneducated, and unenlightened, through science, literacy, and education people could see for themselves the power and corruption that held them down and began to throw off their chains of bondage and demand rights.
Instead of the divine right of kings people demanded the natural right of democracy. Democratic elections, in this sense, are scientific experiments: every couple of years you carefully alter the variables with an election and observe the results. Many of the founding fathers of the United States, in fact, were scientists who deliberately adapted the method of data gathering, hypothesis testing, and theory formation to their nation building. Their understanding of the provisional nature of findings led them to form a social system wherein empiricism was the centerpiece of a functional polity. The new government was like a scientific laboratory conducting a series of experiments year by year, state by state. The point was not to promote this or that political system, but to set up a system whereby people could experiment to see what works. That is the principle of empiricism applied to the social world.
As Thomas Jefferson wrote in 1804: "No experiment can be more interesting than that we are now trying, and which we trust will end in establishing the fact, that man may be governed by reason and truth."