Empiricism is a philosophical view that experience, especially sensory perception, is the key source of human knowledge.
17 - 18 century - British Empiricism focuses on philosophers such as John Locke, George Berkeley, and David Hume, who prioritized sensory knowledge over reason.
19 - 21 century - Empiricism faces challenges in justifying knowledge of unobserved things, like sub-atomic particles or evolution, since it relies on direct experience.
Empiricists reject the idea of innate knowledge or ideas that exist independently of experience.
The contrast to empiricism is Continental Rationalism, represented by Descartes, Spinoza, and Leibniz, who emphasized reason and innate ideas.
Empiricism has its roots in earlier philosophers like Aristotle, who rejected Plato’s theory of innate knowledge and instead emphasized sensory experience as the path to understanding reality.
Medieval thinkers such as Thomas Aquinas and Roger Bacon also laid the groundwork for empiricism by asserting that knowledge begins with sense perception.
Lockean Axiom: There is no idea in the mind that cannot be traced back to some particular experience.
Locke expanded the definition of "experience" to include both sense-perception and introspection.
Sensory ideas relate to qualities perceived through the five senses: sight, touch, smell, hearing, and taste.
These internal operations include thinking, doubting, believing, reasoning, and willing.
Locke argues that we experience both external objects and the workings of our own mind.
His goal is to show that all knowledge can be traced back to either external perception or internal reflection.
Locke distinguished between primary qualities (such as solidity, extension, motion, number) that exist in objects themselves and secondary qualities (like color, taste, and sound) that are dependent on human perception.
Berkeley argued for immaterialism: reality consists only of minds and their ideas.
He claimed that the existence of objects is dependent on being perceived.
He argues that ideas only exist by being perceived, and that external objects are also collections of ideas.
Berkeley uses the Lockean Axiom, which states that all ideas can be traced back to experience.
He concludes that objects in the external world exist only when they are perceived, as they are essentially ideas.
Berkeley's view hinges on the notion that perception forms the basis of our understanding of the external world.
P.S.
One way to think about what Berkeley is effectively doing here is simply exploring some of the logical consequences of Locke’s view that a) our knowledge of the world is a set of ideas, and b) the only sources of those ideas are sensory experiences and introspection of our own ideas and reasoning about them. That is, he is exploring the consequences of a strict empiricist approach to knowledge. His conclusion is that if our knowledge consists of a) ideas in our minds and b) mental analysis of the relations of those ideas, i.e. reasoning with them, then it is at least logically possible that no material, physical world outside of minds filled with ideas and capable of reasoning about them need exist. He would say that empiricists who posit knowledge to be about a real physical world at least owe us a detailed justification of why a belief in the existence of such a physical world is a necessary part of their story. Berkeley’s epistemology is a radical form of internalism in which God supplies us with beliefs (ideas) and we carry on our lives by manipulating those ideas, including justifying some of them as “knowledge” using other ideas.
Hume was skeptical of causation, arguing that we don’t directly experience causal connections. Instead, we infer causation from observing repeated events.
He introduced the idea that we form impressions (direct experiences) and ideas (memories or imaginations of impressions), but these ideas can never fully capture the vividness of direct impressions.
His reasoning is based on a version of Locke's Axiom: no idea can exist without being traced to an experience.
Hume’s skepticism about causation stems from his empiricist view that we cannot directly experience causation.
Human knowledge is limited: we can’t know if causes always produce the same effects.
We only observe the correlation and order of events (C and E), not the necessity we attribute to them.
Hume’s commitment to empiricism leads him to conclude that belief in necessary causation isn’t certain and shouldn’t be considered true knowledge.
In the modern era, empiricism faces challenges, particularly in scientific fields where knowledge is derived from unobservable phenomena (e.g., sub-atomic particles or evolutionary processes). These require indirect forms of evidence, raising questions about how empiricism can account for knowledge beyond direct sensory experience.