George Berkeley's Subjective Idealism

Bishop George Berkeley (1685 to 1753)

From an early age, George Berkeley questioned everything. As an adult he concluded that this mysterious “matter” upon which Empiricists base their approach to reality is something that has no appearance in the world. Logically, we are bound to discredit such an imaginary entity. Berkeley put his finger on the weakness of empiricism by demonstrating that many qualities of objects that can be shown to exist not in the object, but only in the mind of the perceiver. Only what we experience can be said to be real. Or, to express it another way: The existence of things consists of their being perceived by the mind.

Berkeley is a subjective Idealist. He built upon the thought of Plato, believing that the mind or “nous” is able to re-cognize objects because it is an expression of the eternal soul. Here Bishop George Berkeley’s religious beliefs find expression. Berkeley's views require God to be present as an immediate cause of all our experiences. God is not the impersonal engineer of Newtonian machinery that in time leads to the growth of a tree in the university's quadrangle. Rather, the individual’s perception of the tree is an idea that God's mind has produced in the individual and the tree continues to exist in the Quad when nobody is there to see sense it because God is an infinite mind that perceives all. This position is called “panentheism.”

Berkeley influenced the skepticism of David Hume who insisted that unless something can be demonstrated to be a universal, it should not be used as an epistemological foundation.

Berkeley maintains that individuals can only directly know sensations and ideas of objects, not abstractions such as “matter” or “substance”. He denied the existence of substance, defined as something essentially inert or passive. He argued that there are only two ways for something to have a claim to existence: either by perceiving, or by being perceived.

Berkeley believed that Locke and other empirical philosophers caused the general public to become skeptical about the value of the philosophical project and to doubt even religious truths. He argued that it is inevitable that people should become skeptical about everything when they base their ideas about reality on false principles.


Philonous and Hylas Discuss Reality

In this enactment, Philonous (lover of the mind) represents George Berkeley’s subjective Idealism and Hylas (Greek word for matter) represents John Locke’s Empiricism. The enactment is adapted from Berkeley’s Three Dialogues between Hylas and Philonous (1713) in which Berkeley develops his "Esse est percipi" that is, “To be is to be perceived.”


Hylas: My dear Philonous, last night in conversation I heard the most outrageous thing about you.

Philonous: And what might that be?

Hylas: That you are a great skeptic who denies the existence of material substance or matter.

Philonous: That there is no such thing as what Philosophers call material substance is certainly true. But my opinion is neither skeptical nor opposed to common sense.

Hylas: But it is absurd to deny the existence of sensible things. How can you say that a material object has no existence?

Philonous: What do we perceive immediately by our senses? Only colors, shapes, sounds, tastes, odors and tangible qualities such as weight. Sensible things therefore are nothing else but so many qualities that we sense?

Hylas: I grant that. But to exist is one thing and to be perceived is another.

Philonous: If this be so, then heat must exist outside the mind, correct?

Hylas: Quite so. The heat we perceive exists in the object that occasions it.

Philonous: Let us examine whether this be true. Suppose one of your hands is hot and the other cold, and now they are both put into the same vessel of water in an intermediate state; will not the water seem cold to one hand and warm to the other?

Hylas: That is so.

Philonous: But by logical principles, isn’t it absurd to say that the object – water, in this case – has in itself simultaneous properties of cold and warm?

Hylas: Without a doubt, it seems absurd. Yet, I still believe that things that can be sensed have an objective reality outside the mind.

Philnous: Let us consider the case of a flame of extreme heat. Extreme heat causes pain, does it not?

Hylas: Certainly, yet the heat is in the flame.

Philonous: You say that the heat exists in the flame. It follows by your principle that pain must be in the flame also.

Hylas: No one can say that pain is in the flame. I see now where I have gotten off the track. It is necessary to distinguish between the pain, which is in the mind, and the heat, which is a material object.

Philonous: If this be so, then put your hand in the fire and tell me if you feel two things, heat and pain, or only one thing, pain.

Hylas: Yes, I see what you are saying. I am content to yield on this point that heat and cold are only sensations in the mind, but there are other qualities that demonstrate the reality of external things.

Philonous: Then let us consider them one by one, beginning with the qualities of sweetness and bitterness.

Hylas: Can any man in his right senses doubt whether sugar is sweet and wormwood bitter?

Philonous: Yet different people perceive different tastes in the same food. How can this be, if the taste is inherent in the food?

Hylas: Yes, that is true. I don’t know how it is so.

Philonous: Let us then consider the case of colors.

Hylas: Excuse me! Can anything be plainer than that we see the color on the object?

Philonous: Then the beautiful red and purple we see on yonder clouds are really in them?

Hylas: Those colors are not really in the clouds, but only appear to be from this distance.

Philonous: How then are we to distinguish these apparent colors from real colors?

Hylas: That’s easy. Apparent colors vanish upon closer inspection.

Philonous: Then those colors are real that can be discovered upon the most near and exact inspection, such as through a microscope?

Hylas: Certainly.

Philomous: But a microscope often reveals colors in an object that are not seen by the naked eye. So which colors are real and which apparent? Is it not obvious that colors appear different in changing light and from different distances? If this be so, we can’t say that color is inherent in the object.

Hylas: I admit, my dear Philonous, that in the case of colors, they exist in our perception not in the objects themselves. But what of sound? Is it not a fact that sound waves exist and travel through space?

Philonous: But are sound waves sensible? Do we feel them? Is there any sound when a tree falls in a forest and no one is there? If sound waves were sensible then we would feel them when a tree falls, but we do not. Doesn’t this demonstrate that sound is experienced noise and not something outside the mind?

Hylas: But it simply cannot be that the objects we perceive are only ideas in our minds and do not have an objective reality independent of and outside of our minds!

Philonous: I do not wish to appear unreasonable, friend. If you can conceive it possible for any mixture or combination of qualities to exist without the mind, then I will grant it to be so.

Hylas: What could be easier than to conceive a tree or a house existing by itself, independent of and unperceived by the mind. I can conceive of them both at this very moment!

Philonous: But as soon as you imagine this tree and this house, they exist in your mind! Don’t you see, Hylas, that all we can know is what we experience as ideas in our mind. The existence of things consists of their being perceived by the mind. Or, to express this more precisely: to be is to be perceived.