A Treatise Concerning the Principles of Human Knowledge

In Sections 34-84, Berkeley deals with a series of thirteen objections to the principles thus far outlined. These objections are specifically related to philosophy or science; Berkeley will later deal with religious objections. This group of sections shows Berkeley’s careful and thorough consideration of opposing points of view, typically introduced at the head of paragraphs with phrases like “you will perhaps say” (57) or “But, say you” (60). This part of the book represents a self-imposed test for Berkeley’s arguments. By presenting alternative or opposing views—building on the methods of such previous philosophers as Socrates and Thomas Aquinas—Berkeley bolsters his own views.

Objection 1: Berkeley’s scheme abolishes concrete things in the world around us, replacing them with “a chimerical scheme of ideas” (38).

Berkeley replies that his scheme does not deny the existence of things; it merely denies the existence of “matter or corporeal substance” (39). Berkeley emphasizes that far from leading to skepticism about sense knowledge, his scheme reinforces faith in the senses, as he will show later.

Objection 2: There is a great difference between the real and the imagined—between, for example, thinking about fire and actually being burned.

Berkeley replies that he does not deny this; he only insists that the feeling of being burned exists in the mind and senses, just as thinking about fire does.

Objection 3: Berkeley’s scheme suggests that things physically far off from us are only in the mind, just like our thoughts.

Berkeley replies that in a dream we often do perceive things existing a great distance away, yet those things too exist only in the mind.

Objection 4: Berkeley’s scheme suggests that things pop in and out of existence (“are annihilated and created” (46)) depending on whether we are perceiving them or not.

Berkeley simply reiterates that it is impossible to imagine things existing without them being perceived; thus, existence and perception are tied in together.

Berkeley observes that the idea is not alien to other philosophies. Some philosophers have asserted that light and colors are “mere sensations that exist no longer than they are perceived” (44). Berkeley merely extends this to other objects of sense. Moreover, Scholastic philosophers have argued that God continually maintains all things in existence as a sort of “continual creation.”

Further, as implied in Part 1, Section 6, it is not the case that things cease to exist while I do not perceive them, because they may during those intervals be perceived by some other spirit, including God.

Objection 5: If qualities (e.g., “extension and figure”) exist only in the mind as Berkeley claims, then it would appear that the mind itself has those qualities (e.g., being extended and figured). This objection relies on the assumption that accidents (qualities or attributes) inhere in a substance (see Index of Terms for more discussion).

Berkeley rejects this view, inherited through Aristotle and the Scholastic philosophers. A thing is not something distinct from its qualities and attributes. Thus, for example, we shouldn’t say that an apple “supports” the quality of redness; rather, redness is part of being an apple.

Objection 6: To deny the existence of matter is to reject the advances of science.

Berkeley replies that everything that science has discovered can just as well be explained without the existence of matter. Further, science does not depend on the existence of matter as such, but on such things as number or motion— which are ideas or qualities of things—and on how these ideas or qualities affect human beings. Matter, Berkeley reiterates, is powerless to affect spirits in any way.

Objection 7: Berkeley’s system is irrational because it seems to “take away natural causes and ascribe everything to the immediate operation of spirits” (47). It would be absurd to stop saying “fire heats” and instead say “spirit heats.”

Berkeley agrees that this would be an absurd use of language, and he argues that in this case it is best to “think with the learned and speak with the vulgar” (47). That is, the philosopher must use common everyday language so that he will be understood by most people, while understanding the philosophical truth hidden under those terms, inaccurate in a literal sense though they may be.

Moreover, some ancient and modern philosophers have in fact held that there are no natural causes, and that God directly causes all things. Berkeley only disagrees with them to the extent that they did not go far enough in admitting that there is no such thing as matter and that only spirit has the power of acting.

Objection 8: The fact that most of the world believes in the existence of matter seems a convincing argument in its favor. How can the majority of humanity be wrong?

Berkeley answers by arguing, first, that not as many people believe in matter and external things as commonly supposed. Many people believe by habit that their sensations are caused by “some senseless unthinking thing” (48), but at bottom this proposition has no real meaning for them. People are aware that they have sensations that do not arise from their conscious will, and they must ascribe some cause to them, so they assume they must come from material objects themselves. It does not occur to them to ascribe them to the activity of a spirit, i.e., God, because God is not visible.

(Berkeley seems to jump from Objection 8 to Objection 10. In the place of what should be Objection 9, he extends his argument from the previous objection.)

It is possible that the vast majority of humanity might be wrong about something. There are many widespread “prejudices and false opinions” (49); at one time the idea that the earth revolved around the sun was regarded as a “monstrous absurdity,” but it has since been scientifically proven.

Objection 10: Berkeley’s scheme is inconsistent with settled truths in science, such as the motion of the earth around the sun.

Berkeley replies that his scheme is consistent with such truths as it deals only with what we perceive to be true, which is also what science deals with.

Objection 11: If matter does not exist, then why are things in nature (e.g., the human body) so intricately organized?

Berkeley responds that while the operation of God’s providence is sometimes mysterious, this objection shrinks next to the “truth and certainty” (52) of his previous conclusions about spirit and matter. Further, the objection could just as well be applied to other philosophies. Even if we assume that matter exists, why does God act through complex “instruments and machines” instead of causing things “by the mere command of His will” (52)?

To this question Berkeley responds that it is necessary for God to act through intermediary processes and mechanisms in order for things to work “in a constant regular way according to the laws of nature” (53). While occasionally God may deem it necessary to produce a miracle in order to “surprise and awe men into acknowledgement of the Divine Being” (54), as a rule He works according to the natural laws He has established, which themselves provide persuasive evidence of His being.

In discussing how different ideas are connected in our mind, Berkeley makes a distinction between a cause and a sign. A particular thing in nature may be a sign for another thing without being its cause. God uses things in nature as signs that point to Him. The job of the scientist (“natural philosopher”) should be to discover in nature “marks or signs for our information” (55) rather than to interpret those things as “corporeal causes” of other things. Berkeley would prefer that we speak of things in nature as being signs rather than causes, and to reserve the term “cause” to describe God as the creator or instigator of all things.

Objection 12: Even if we agree with Berkeley that matter does not exist outside the mind, yet it is possible that God uses matter as an occasion for implanting ideas in our minds.

Berkeley answers that this claim runs into contradictions. Something that is inert and passive cannot be an occasion for something, which implies that it has active power. Second, the claim implies that matter is a substance without accidents (see Index of Terms) and something that does not exist in a place, both of which are absurd.

Berkeley declares outright that “we have no longer any reason to suppose the being of matter” (59). According to Berkeley, his new doctrine is an advance over previous beliefs about reality. The philosophy of Berkeley’s day held that material things had primary and secondary qualities. Primary qualities included figure, motion, and extension, while secondary qualities included colors and sounds. Natural philosophers adopted the view that primary qualities were basic building blocks of the things themselves, whereas secondary qualities were simply a matter of our sense perceptions.

Berkeley further argues that the primary qualities too are no more than ideas in our minds, not inherent properties of things. Since color and sound do not exist outside of the mind, it follows that figure and motion do not either; thus, we can discard the idea of matter itself.

Objection 13: Even if we agree with Berkeley that material substance does not exist, we could still keep the idea of matter as “an unknown somewhat” [i.e., something] (61) that is defined negatively—not spirit, not idea, inert, thoughtless, etc., etc.

Berkeley replies that this is equivalent to calling matter nothing, and this merely proves his point that matter does not exist.

Finally, Berkeley briefly considers a few objections on the part of religion. Being himself a Christian clergyman, these objections would have been of particular moment for him.

The Bible assumes that material bodies exist and are real. Further, miracles depend upon the existence of material objects. The question arises, then, if they merely illusions of the senses, according to Berkeley’s system.

Berkeley replies first that the Bible speaks in the language of the common person, and in common language material things are assumed to exist. In common language, we describe things “as they are known and perceived by us” (63). Thus, the Bible’s teachings are not endangered by Berkeley’s system. The existence of matter in the scientific sense is nowhere mentioned in the Bible.

As to miracles, Berkeley reiterates that he does not deny the existence of things in the world. What he denies is the existence of matter.

These religious objections highlight the fact that throughout their history, the fields of philosophy and religion have been sometimes complementary, sometimes antagonistic.