Concept

Empiricism

Intro

Empiricism says everything we know, or just about everything, comes from our five senses. We are born as blank slates (John Locke's famous phrase: tabula rasa). Experience writes on us. Take experience away and there is nothing left to know.

This is the official philosophy of modern science and a lot of modern atheism. Hume, Locke, and Berkeley are the British founders. Hume took it to its sharpest edge: if a claim cannot be checked by sense experience, throw it away as meaningless. That is the move modern atheists use against theology: "You can't see God. You can't measure Him. So you can't really know He exists."

There are real strengths in empiricism. Testing, evidence, and observation matter. The scientific revolution would not have happened without taking sense experience seriously.

There are also serious problems with the strict version. First, the rule "all knowledge comes from sense experience" cannot be checked by sense experience. It is a philosophical claim about how knowledge works, which means the rule fails its own test. Second, math and logic are not learned from sensation. We do not see "two plus two equals four" through a microscope. Third, our minds clearly contribute things sense experience cannot supply: the categories of cause, space, and time, which Kant argued were built in. Fourth, on strict empiricism, you cannot know other minds exist (you only see bodies), you cannot know the past existed (you only have current memories), and you cannot know induction is reliable (Hume's own problem).

For Christian apologetics, empiricism matters because the New Atheist demand for "scientific proof of God" assumes empiricism is the only legitimate way to know things. Once empiricism's own limits are out in the open, the demand loses force. Knowledge comes through multiple channels: sense experience, reason, intuition, testimony, conscience, and (Christians add) revelation.

In full

Empiricism is the epistemological position that all (or substantially all) knowledge derives from sense experience. The mind, on a strict empiricist account, begins as Locke's tabula rasa, a blank slate, onto which experience inscribes ideas through sensation and reflection. Empiricism stands opposed to Rationalism, which holds that some knowledge is a priori / innate, accessible through reason alone.

Core claim

The empiricist principle (Locke's formulation, Essay Concerning Human Understanding II.1.2):

"Let us then suppose the mind to be, as we say, white paper, void of all characters, without any ideas… Whence comes it by that vast store, which the busy and boundless fancy of man has painted on it with an almost endless variety? To this I answer, in one word, from experience."

Stronger formulations (Hume, the logical positivists) add that any meaningful synthetic claim must be empirically verifiable in principle. Weaker formulations grant that mathematics and logic are a priori but insist that all substantive knowledge of the world is empirical.

Historical development

Ancient and medieval roots

Aristotle, De Anima III.4-5 and Posterior Analytics II.19, the famous dictum (later Latinized in scholastic thought as nihil in intellectu nisi prius in sensu, "nothing in the intellect that was not first in the senses").
Thomas Aquinas, Summa Theologiae I.84.6, adopts Aristotle's empirical principle while affirming the active intellect's abstraction of universals from sensible particulars.

British Empiricism (the canonical trio)

John Locke, Essay Concerning Human Understanding (1689), the founding modern empiricist text. Two sources of ideas: sensation (outer experience) and reflection (inner experience). Distinguishes primary qualities (extension, motion, number, in objects) from secondary qualities (colour, taste, produced in us).
George Berkeley, A Treatise Concerning the Principles of Human Knowledge (1710); Three Dialogues Between Hylas and Philonous (1713), idealist empiricist. Esse est percipi ("to be is to be perceived"). Eliminates material substance; reality consists of minds and their ideas, ultimately sustained by the divine Mind.
David Hume, A Treatise of Human Nature (1739-40); An Enquiry Concerning Human Understanding (1748), radical empiricism. Distinguishes "impressions" (vivid) from "ideas" (faded copies). All meaningful concepts must be traceable to a prior impression. Famously skeptical about causation, induction, the self, miracles, and natural theology.

20th-century logical positivism / logical empiricism

The Vienna Circle (1920s-30s) gave empiricism its most linguistically explicit form via the verification principle: a synthetic statement is meaningful only if empirically verifiable.

Moritz Schlick, General Theory of Knowledge (1918, rev. 1925).
Rudolf Carnap, The Logical Structure of the World (1928); The Logical Syntax of Language (1934).
A. J. Ayer, Language, Truth and Logic (1936), the most popular Anglo-American statement; declared theology, ethics, and metaphysics literally meaningless ("non-cognitive").
Otto Neurath, Hans Reichenbach, Carl Hempel, collaborators.

The verification principle collapsed under its own weight by mid- century (the principle is itself not empirically verifiable; Quine's "Two Dogmas of Empiricism," 1951, dissolved the analytic/synthetic distinction it required).

Strengths

Empirical sciences: empiricism captures the methodology of modern natural science, observation, experiment, replication, falsification.
Anti-dogmatism: requires beliefs to be grounded in something beyond mere assertion.
Cognitive plausibility: human concept-formation does seem to begin with sensory experience (developmental psychology supports the broad claim).

Weaknesses

1. Self-refutation (the master critique)

The empiricist principle, "all knowledge derives from sense experience", is itself not derived from sense experience. It is a philosophical / a priori claim. On its own criterion, it fails to count as knowledge. The same applies to the verification principle: "a statement is meaningful only if empirically verifiable" is itself not empirically verifiable.

This is the standard self-refutation objection (see Self-refutation), pressed by Christian philosophers (Edward Feser, The Last Superstition, 2008; J.P. Moreland, Scientism and Secularism, 2018) and secular critics (Putnam, Quine).

2. The problem of induction

Hume's own analysis (Enquiry §IV-V): we have no empirical justification for the inference from past regularities to future ones. The principle "the future will resemble the past" is itself either a priori (which empiricism rejects) or based on past experience (circular). This destabilizes the empirical sciences from within.

3. Universal and necessary truths

Mathematics ("2+2=4"), logic (the law of non-contradiction), modal truths (necessity, possibility), and ethical universals are necessary, they hold in every possible world. But sense experience only gives contingent particulars. Empiricism cannot ground necessary truth without either denying it (Mill, A.J. Ayer) or relaxing into rationalism.

4. Abstract objects, other minds, the past

Numbers, propositions, sets, other minds, historical events, none are directly sense-experienceable. Empiricism either eliminates them, reduces them to sense-data (phenomenalism), or admits non-empirical knowledge.

5. The criterion problem

Sense experience itself is interpreted via concepts not given in experience (Kant's reply to Hume, Critique of Pure Reason, 1781). Pure empirical "givenness" may be a myth (Sellars, "Empiricism and the Philosophy of Mind," 1956).

Christian engagement

Christian philosophy has had a complex relationship with empiricism:

Aquinas / Thomism is moderate empiricist, accepts nihil in intellectu nisi prius in sensu while affirming the intellect's abstractive power and natural-theological inference from sensible effects to God (the Five Ways).
Berkeley uses empiricism for theism: external reality requires a perceiving Mind, which is God.
Hume uses empiricism against theism: in Dialogues Concerning Natural Religion (1779) he attacks the design argument, miracles ("Of Miracles," Enquiry §X), and the cosmological argument.
Reformed Epistemology (Reformed Epistemology) rejects strong empiricism's evidentialist demand: belief in God can be properly basic without inferential evidence.
Scientism is empiricism radicalized into the claim that only science yields knowledge, usually deployed against theology.