Empiricism

John Locke's 1689 proposition that the mind begins as a "tabula rasa" (blank slate) was philosophically radical and politically explosive. If we're not born with innate ideas about divine right or natural hierarchies, then kings have no God-given authority and social structures become negotiable human constructs. This seemingly abstract epistemological claim became ammunition for democratic revolutions and challenges to inherited power across Europe and America.

Bishop George Berkeley took empiricism to its most counterintuitive extreme: if all knowledge comes from sensory experience, and we only ever experience our perceptions, then material objects don't exist independently at all—"to be is to be perceived." His idealism wasn't skepticism but theology: the world persists when we're not looking because God is always perceiving it. Empiricism's logical endpoint became a defense of divine omnipresence, shocking both materialists and fellow empiricists.

David Hume identified what philosophers call the "problem of induction": no amount of past experience can logically guarantee future patterns. You've seen the sun rise a thousand times, but that doesn't prove it will rise tomorrow—you're just psychologically habituated to expect it. Every scientific law rests on this shaky foundation, meaning our most reliable knowledge is technically just confident habit, not logical certainty.

Empiricism faces its greatest challenge with mathematical truth: we know 2+2=4 without checking every possible pair of objects in the universe, and we know it with certainty no sensory experience provides. Mill tried to make math empirical (really just generalizations from experience), while others admitted reason must supplement experience. This tension reveals that pure empiricism, taken seriously, might undermine the very logic needed to do science.

Before empiricism, physicians trusted ancient texts and rational deduction more than observation—bloodletting persisted for millennia despite killing patients because it made theoretical sense. The empiricist revolution insisted on looking at actual outcomes, measuring results, and trusting data over authority. Today's randomized controlled trials, evidence-based medicine, and "show me the numbers" skepticism are all empiricism's practical children, saving millions of lives by privileging what works over what should work.

"Empiricism" derives from the Greek "empeiria" (experience), which also gives us "empirical" and, surprisingly, "quack"—medieval "empirics" were medical practitioners who learned through trial-and-error rather than university training. This dual legacy captures empiricism's tension: it's both the foundation of rigorous science and a reminder that raw experience without theory can be dangerously misleading. The quacks and the scientists both claim experience as their teacher.