Empiricist Epistemology,Locke, Berkeley and Hume

Empiricism stresses the power of a posteriori reasoning — reasoning from observation or experience — to grasp substantial truths about the world.

When a priori ideas conflict with the a posteriori, the a posteriori wins, according to empiricism.

Empiricism is usually opposed to rationalism

- the view that reason rather than sensation or observation is the source of knowledge.

Empiricists tend to see modern science as the paradigm of knowledge. The empiricist approach is hands-on, down-to-earth. Empiricists urge us to trust our senses, observe the world carefully, perform experiments, and learn from experience.

So, empiricists would say, we should be suspicious of explanations that make reference to non-observable entities such as gods, souls, immaterial minds, and other metaphysical concepts not verifiable by the senses.

British Empiricism was a movement in epistemology in the modern period of philosophy. The major figures of British Empiricism are Locke, Berkeley, and Hume. The ancient Greek philosopher Aristotle is usually considered a forerunner of modern empiricism. For example, he criticized Plato’s very non-empirical notion of transcendental forms.

The “British Empiricists” were:

· John Locke (1632-1704)

· George Berkeley (1685-1753)

· David Hume (1711-1776)

John Locke was an English philosopher and physician regarded as one of the most influential of Enlightenment thinkers and known as the "Father of Classical Liberalism". Considered one of the first of the British empiricists, following the tradition of Sir Francis Bacon, he is equally important to social contract theory. His work greatly affected the development of epistemology and political philosophy. His writings influenced Voltaire and Rousseau, many Scottish Enlightenment thinkers, as well as the American revolutionaries. His contributions to classical republicanism and liberal theory are reflected in the United States Declaration of Independence

There are no innate ideas

Locke spends the entirety of Book I in his Essay arguing that human beings have no inborn, or innate, ideas in their minds at birth. Some of the rationalist philosophers wanted to claim that when a human mind comes into the world it already understands such fundamental principles as the principle of non-contradiction - that a thing cannot both be and not be at the same time in the same respect - and the principle that the whole is more than the part. Locke does not believe that we are born with any of these inborn ideas.

Locke believes that when a human mind is first born - whether the birth of that human mind be dated at the moment of parturition (birth), or earlier at the moment of conception, or at some point in between - when the human mind first comes into existence it does not come with any inborn ideas. When it first exists it is a blank slate, a "tabula rasa," an empty surface on which experience will then subsequently write all that we ever know. We may be born with automatic instinctual behaviors - such as automatic reflex motions in response to some stimulus - but these are not ideas or perceptions or what today we might call "contents of consciousness."

All ideas come from experience

All contents of consciousness, that is, everything that ever gets into the mind, comes into it from one source only, and that source is experience. Experience is the one source of input into the human mind.

There are two kinds of experience, for Locke.

a. Experience of the outer world, which he terms sensation, and from this mode of experience we derive such notions as blue, round, solid, smooth, heavy, large, etc.

b. Experience of the inner world, which Locke terms reflection, and from this mode we get such notions as fear, love, willing, doubting, affirming, thinking, feeling, believing, remembering, planning, anticipating, and so on.

Simple and complex ideas

There are basically two sorts of ideas, simple and complex. Simple ideas include all our simple sensory sensations such as red, cold, sweet, loud, soft, round, etc.

Complex ideas are complexes of simple ideas. For example, my sensory experience of a red ball would include a mixture of the simple ideas of red, round, hard, cool, etc. That complex of simple sensations goes into making up my experience of the ball. That is to say, the sensation of this red ball that is in my mind right now, i.e., the "idea" of the ball, derives from the sensory experience of the ball that I am presently experiencing.

Three kinds of complex ideas are built from simple ones:

-compounds (“red house” = "red" + "house");

- relations (“taller than,” “loves”)

- abstractions which lead us to general ideas, e.g., “blue”, “dog.”Abstraction” is the name of a mental process by which general ideas are generated from particular ideas.

Ideas are caused in us by qualities

Ideas (or sensations) in minds are caused by qualities in things. For example, the sensation (or idea) of red in my mind is caused by the quality of red in the thing.

So we now need a definition of what a quality is. Here it is: A quality is a power in a thing to cause an idea in a mind. So a quality is not a thing, really, but is a power in a thing to cause an idea in a mind.

Now this is where it gets interesting. There are two kinds of qualities, according to Locke, primary and secondary.

Primary qualities are those that every physical object, every body, must have. Primary qualities are actually in the physical object. There are only six primary qualities:

solidity (bulk)figure (shape)extension (size)motion/restnumbertexture

Every physical object, in order to even be a physical object, must (according to Locke) have solidity, must have some shape and size, must be either in motion or at rest, must be either one or many, and must have some texture.

Secondary qualities, on the other hand, are nothing but powers in things to produce a sensation in a mind. Now this is an idea that we will need to explore in a bit more detail.

· Representative (or Critical) realism” is Locke’s view that we experience objects indirectly through “representations”.

· The mind represents the world, but does not duplicate it. Descartes also held this view.

· Representative realism is opposed to naïve realism, the view that the mind literally duplicates or “mirrors” external reality.

· Primary qualities are measurable using numbers (e.g., size, weight). They represent the world as it is “objectively”, the same for everyone.

· Secondary qualities result from the interaction of sense data with our sense organs, i.e., they are “subjective” in the sense that the powers that produce them (corpuscles interacting on our senses) are nothing like the ideas themselves

Consider the color red. For Locke red does not actually exist outside of minds (extramentally). Rather it is only an idea in our minds caused by a certain quality of objects in the extramental world. In the case of color the quality or power that produces the idea of red in our minds is electromagnetism. [Locke did not actually know about electromagnetism, and thought light was made of particles (partially correct)]

The idea of red is caused in humans and other animals with similar optic neurology by waves in the electromagnetic spectrum with a frequency of just under 700 nm's.

When those waves hit our optic nerves they cause the sensation of “red.”

So red and all color is intramental or mind-dependent. It does not actually exist in the “real” world.

What is Sound?

So Locke's notion is that everything we perceive besides the six primary qualities (solidity, size, shape, texture, number, and motion/rest) are all secondary qualities. They aren't really out there in the world in the way we think they are. Sound isn't really out there in the world in the way we think it is. Nor is color. Nor is temperature, taste, smell, and so on. Neither are other sensations, like pain, for example. We all realize that the pain we experience is not actually out there in the world. We realize that pain is a sensation we have in our brain/mind and that it is caused by something out there in the world (a needle, a burn, etc) which is not itself pain. It is just the cause of pain. We know the same thing about the sensation of tickle, that it is not out there in the world. There may be a feather out there in the world that some cruel person is maliciously applying to us, but we realize that the tickle is purely a sensation that exists in our mind (or brain). Well, Locke just wants us to realize that all our other sensations (except the six primary qualities) are also just in our minds

Four kinds of existents

1. He believes there are selves (or minds). He believes that we know about the existence of minds both our own and those of other people -- by a process he terms "intuiting."

2. The second kind of existent Locke calls ideas, i.e., the contents of minds. He believes we know about the existence of ideas by reflection.

3. The third kind of existent is things, or physical objects. Locke believes that we know about the existence of things through sensation.

4. Fourthly, Locke believes that there is a God, and that we know about God's existence by logical proofs for his existence. (We will not be looking at any of the classical arguments for the existence of God, but if you ever take a Philosophy of Religion course you will learn about them there.)

Finally, there are two key questions Locke considers it important to ask, and it may even be that the asking of these two questions is more important than the specific answers Locke gives to them.

1. The first question is this: Can we know that things continue to exist during the intervals that they are not being observed by anyone? For example, imagine that you are perceiving the mug on your desk, but that you then turn away from it so that you are no longer perceiving it in any way (and neither is anyone else). You do not see it, feel it, hear it, smell it, or perceive it in any way (and neither does anyone else). Then you turn back and perceive it again. Then you turn away and are no longer perceiving it. The question is this: during the intervals that the mug is not being perceived, can we know that it continues to exist during those intervals?

This may seem like a silly question, but when one is doing epistemology it is important to examine closely the assumptions that are made about what it is possible to know. And Locke is willing to examine this assumption we all seem to have, that things somehow continue in existence even though no one is perceiving them. So that's question number one.2. The second question is this: Even during the times that we are directly observing an object can we know for sure that the object actually exists

The Problem of Substance

Both Descartes and Locke conclude there’s a real substantive world “out there” that has certain qualities (the primary qualities). The primary qualities are qualities of the underlying “substance” (from sub (under) and stance (standing)).

But try this thought experiment. Can you actually perceive the so called substance that is supposed to underlie the qualities of things? Close your eyes and imagine substance without any qualities. Of course this is impossible.

But if Locke is committed to the view that all knowledge comes from the senses, he can’t allow that we know substance, since we have no sensation of substance (we have sensations only of the qualities).

Thus an essential element of Locke’s empiricist philosophy remains unsupported (and unsupportable) by Locke’s empiricist principles.

It appears that Locke's empiricism is not “pure” enough. It is still tainted by non-empirical notions of metaphysical entities like God and substance.

Berkeley and Hume wield Ockam's razor try to make empiricism more pure as we will see in later lectures.