There is a useful word for work like surveys and experiments that seeks to generate knowledge by collecting and interpreting observations: empirical. The philosophy that motivates such work, empiricism, offers sound advice to anyone curious about anything: “Go see for yourself. Don’t trust what common sense says. Don’t trust what other people say—not even experts. Make your own observations.”

    Those observations should be collected carefully, for people are prone to errors in perception and judgment and memory. If you rely on only your recollections of your mere impressions, your observations are just barely empirical.
    Care is also essential in the interpretation of observations, for they can be misleading. But careful observations collected systematically and interpreted prudently foster insights into this complex universe of ours—insights that can take us far beyond common sense, insights that have often proven experts wrong.
    Enunciated here is the philosophy of science, a unique tradition of inquiry that may be humanity’s finest achievement. Science vastly amplifies the power of our minds and our hands. Through science we have become privy to mysterious secrets of nature, created vaccines that prevent hideous diseases, and flown explorers to the distant moon.
    The philosophy that motivates and guides scientists, empiricism, can serve all of us well. Indeed, people collect and analyze observations in many walks of life: not only in the sciences but also in engineering, medicine, and agriculture; in human services; in business and industry; sometimes even in the humanities.
    In all these endeavors—wherever people recognize the value of systematic observations—statistics is useful and often essential. It supplies the tools required to organize and summarize the observations and reason out the conclusions that they warrant.

What About Things That We Can’t Observe?

Many happenings are hidden from our eyes and ears. Can we implement the philosophy of empiricism in studying such things as the origin of the universe, the evolution of our species, and the mechanism of the mind? Yes.
    We start by guessing what we would observe if we could observe the phenomenon that we can’t get to, which is to say that we create a theory of it—a scenario purporting to show what is (or was) transpiring there. Then from our theory we reason out a prediction about something else that we can observe. We check the prediction by carrying out the relevant observation, and we revise the theory accordingly.
    With examples from physics, medicine, detective work, and daily life, module 13 tells more about this process of studying hidden happenings by empirical means.

Empiricism and Rationalism in Philosophy

In philosophy (Honderich, 1995), empiricism is a school of thought that stresses the role of the five senses in the construction of knowledge. Classical empiricism began with John Locke (1632–1704), the Englishman who likened the mind at birth to a blank tablet (in Latin, a tabula rasa) on which the senses write messages. An opposing view is rationalism, which supposes the existence of innate ideas and emphasizes the role of reason in the construction of knowledge.
    Locke was no extremist in his empiricism; he regarded knowledge as a product of reason working out connections between ideas derived from sensory experience. Philosophers identify him as the first of the British Empiricists. Others of this school whose names you may already know were George Berkeley (1685–1753) and David Hume (1711–1776).
    Rationalism is a Continental school of thought espoused by, among other, the Frenchman René Descartes (1596–1650), the Dutchman Baruch (or Benedict) Spinoza (1632–1677), and the Germans Gottfried Wilhelm Leibniz (1646–1716) and Immanuel Kant (1724–1804). Don’t think of rationalism as inconsistent with science; Descartes’ philosophy didn’t keep him from making observations and helping develop physics and physiology, and Leibniz’s philosophy, likewise, didn’t keep him from making observations and helping develop geology and linguistics. (Both also made major contributions to mathematics.)
    So what does philosophy have to do with science as science is practiced? Not much. Most scientists have studied little philosophy, if any. Without regard to the debates that occupy philosophers, they just go about their business of making observations and developing theories—putting into practice both empiricism and rationalism.

Can Empiricism Answer All Our Questions?

According to most philosophers (Honderich, 1995), no. Observation cannot answer questions about what is good or bad, right or wrong, moral or immoral. What we see and hear of the universe can tell us what does exist but not what should exist. Questions about what does or does not exist belong to a realm entirely separate from questions about what is or is not good. The latter constitute the realm of values, and observation can answer questions of only the first kind, questions about existence—or so goes the majority opinion among philosophers.