George Berkeley

Treatise Concerning the Principles of Human Knowledge

1. Anyone who considers objects will realize they are ideas imprinted on senses or ideas formed by memory or imagination from those ideas originally imprinted on senses. Sight gives ideas of light and colors and their degrees. Touch perceives hard and soft, heat and cold, motion and resistance and their degrees. Smell furnishes odors. Palate tastes, hearing sounds with various tones and compositions. Overvation of these accompanying each other result in one name, and so to be reputed as one thing. These collections of ideas constitute the things we call by one name like a stone and whether they are pleasing or disagreeable excite the passions of love, hatred, grief, joy, etc.

2. Besides these objects there is something that knows or perceives them and exercises operations like willing, imagining, and remembering them. That perceiving, active being is what he calls mind, spirit, or his self, which is not denoted by any ideas but is wholly distinct and is where those ideas exist (i.e. perceived) for the existence of an idea is in its being perceived.

3. Everybody will allow that thoughts passions and ideas don't exist without the mind. And sensations (or ideas of the senses) cannot exist without a mind to perceive them. He thinks intuitive knowledge of this is possible if one considers how "exist" is applied to sensible things. A table exists if I see it or feel it, a sound exists if it is heard, etc. And it exists when I'm not in my study if I could go into my study and perceive it or some other spirit perceives it. This is all I can understand by such expressions. What can be said about things outside of their relation to being perceived is unintelligible. Esse est percipi and it is impossible that they should have any existence outside of perceiving minds.

4. It is a common view that objects have existence outside of their being perceived. But this involves a manifest contradiction. For what is a house except but the things we perceive by sense, and what do we perceive except for our sensations (ideas).

A note at the top of the page reads, "Berkeley often mentions that he believes anyone who reflects on a subject to come to a similar conclusion."

5. The idea of objects existing outside of perception is based on the doctrine of abstract ideas, for it is abstraction to distinguish the two. What are light, colors, heat, cold, extention but impressions on the senses, and is it possible to separate this from perception? My thoughts can divide things my senses didn't, like the smell separate from the rose but only to the extent that I could perceive those things separated. Since it is impossible for one to see anything without a sensation of that thing, it is impossible to conceive any sensible thing distinct from the sensation of it.

6. Nothing has subsistence without a mind, their being is perceived or known. And if they are not being perceived by any spirit they are either perceived by an eternal spirit or don't exist. He challenges anyone to try and separate in their thoughts the being of a sensisble thing from its being perceived.

7. There is not any other substance than spirit, i.e. that which perceives. Sensible qualities: color, figure, motion, smell, taste, and the like, ideas perceived by sense. No idea can exist in an unpperceiving thing because to have an idea is the same as to perceive, therefore, whenever color and the other sensible qualities exist they must be peceived by the thing so there can't be unthinking substance or substratum of ideas on representation of an external object.

8. An idea can't be like anything but an idea, a color like nothing but another color. The supposed original or external things, which our ideas are representations, are or are not perceivable. If yes, they are ideas, in no, does it make sense to say a color is like something that is invisible.

9. Mentions Locke's primary and secondary qualities: matter is an inert, senseless substance where extension, figure, and motion subsist. All these have been shown to be ideas, therefore, the notion of matter involves a contradiction.

10. If the secondary qualities are inseperably united with the primary qualities, and the secondary qualities exist in the mind, it follows that the primary qualities exist in the mind as well. Can anyone conceive of extension and motion without the other sensible qualities?

11. Great and small, swift and slow, are said to exist nowhere without the mind being relative and change as position of sense organs changes. So extension without the mind is neither great nor small, swift not slow. so it is nothing at all. But if one objects they are extension of motion in general, this just shows the notion depends on abstract ideas. But this is a vague description resembling Aristotle's. Without extension solidity cannot be conceived, so solidity must exist in the mind as well.

12. Number is entirely an idea of the mind, this is evident because the same thing has different denomination of # when the mind views it with different respects, i.e. an inch, a yard. Number is obviously relative, so it is hard to imagine how anyone could think it exists outside of mind. One book, one page, one line is each a unit but each is made up of several of the others, and each unit relates to a particular combination of ideas arbitrarily put together by the mind.


14. Heat and cold, sweetness and bitterness, obviously exist in the mind because the same object can appear to be both at the same time, so why can't the same be said for extension and if eyes from different positions or differing eyes from the same position looks different and is not definite without the mind. And the same of motion since faster succession of ideas in the mind makes things appear slower.

15. In short all the arguments that show that secondary qualities depend on the mind also work for primary qualities. Berkeley admits this doesn't prove that qualities aren't in the objects but it only proves we don't know by sense what is the true extension or color, but he will provide some that prove they all must exist in mind.

16. It is said extension is a mode or accident of matter, and that matter is the substratum that supports it. What does "support" mean here [it's obviously not like a building]? One must at least know what the relation between matter and its accidents is if one doesn't exactly know what matter is.

17. The most accurate philosophers mean the idea of being in general with the notion of it supporting its accidents. The general idea of being seems the most abstract and incomprehensible. And the proponents don't explain "support", so Berkeley is convinced there is no meaning attached to material substance. He makes strange conclusion here.

18. It is possible that solid, extended...substances exist without the mind but how is it possible for us to know that? We must know it either by sense or reason. Sense only gives knowledge of things that are perceived, exist in the mind. Reason infers things from what is perceived. But reason won't lead us to conclude the existence of bodies without the mind, since there is no acknowledged necessary connection between matter and our ideas. Dreams, phrensies show it is possible to be affected with all the ideas we have now, though bodies exist without.

19. But it is not probable that external objects exist and is a likely reason for impressing their sensations on us, because of the mind-body problem, so nothing is clearer inexplicable about this. and it supposes that God created innumerable useless beings.

20. In short, if there were external bodies it is impossible we would come to know it, and a being like us that has his senses affected like ours but assuming without the aid of bodies, he has the same reaon to believe in external objects as we do.

22. All that needs be asked is if anyone looking at their own thoughts whether it can be conceived possible for a sound, figure, motion, or color to exist without a mind? This will show the contradiction. You cannot give any reason why you believe it exists or assign any use once it exists.

23. Imagining books in a closet or trees in a park both supposedly unperceived are in fact being thought of. This shows you have the power to form ideas in your mind, it does not show that you can conceive it possible the objects of thought exist without the mind, which is only possible if you conceive them existing unconceived. When we think of external objects we are contemplating our own ideas.

A note on the top of the page reads, "Berkeley often believes that mere reflection will demonstrate his point."

24. The absolute existence of sensible objects without a mind are words without meaning or a contradiction.

25. Sensations are visibly inactive, there is no power or agency in them, reflection shows this, so that one object of thought cannot produce or alter another because if every part of them only eixst in the mind, then there is nothing in them but what is perceived. The very idea of an idea implies passiveness insomuch as it can't cause anything see 8 shows ideas aren't the resemblance of any active being, therefore, extension, figure, and motion cannot be the cause of our sensations so causation due to atoms and movement are false.

26. There must be a caues of our sensations and their changes. This cause cannot be any idea, quality, or combination of these from 25, it must be a substance, not matter as has been shown, but active substance or spririt.

27. A spririt is one simple, undivided active being, as the spirit perceives ideas it is called understanding, as it produces ideas or operates about ideas it is called will. No idea can be formed of a spirit (or soul) because all ideas are passive and cannot represent something that is active. An idea like motion and change of ideas is impossible. Spirit cannot be perceived but only by its effects. But we have some notion of spirit and the operations of the mind like willing, loving, hating.

28. The mind is active because it can manipulate, create and destroy ideas, but unthinking agents and exciting ideas without volition are merely words.

29. But obviously ideas of sense don't depend on my will so they must be produced by another spirit.

30. Ideas of sense are stronger, livelier, and more distinct than those of imagination, they are also more steady, orderly, and coherent but their admirable connection shows the wisdom and benevolence of their author. The rules that determine how that mind causes in us the ideas of experience are called The Laws of Nature, which we learn by experience where we associate attended ideas.

31. This gives us a sort of foresight, which allows us to regulate our actions for the benefit of life.

32. the consistent uniform Laws displays the goodness and wisdom of governing spirit whose will determines Natuarl Laws, which don't lead our thoughts to him. that people look for second causes. We know we are not in control of the ideas we perceive. When we see the sun we also perceive heat and we make the mistake of thinking one idea causes the other.

33. Ideas of the senses are real things, and ideas of imagination are less regular, vivid, constant, and are copies and representations of former. Both are ideas and must exist in mind. Ideas of sense have more reality, i.e. more strong, orderly, affecting, distinct, and coherent, and have less dependence on the spirit that perceives.

34. He tries to answer some objections and wants to be understood by everyone. First objection, all that is real and substantial is lost and only chimeras are left, everything is purely notional. Answer - everything is just as real, there is a rerum natura so the distinction between reality and chimeras remains.

35. All ideas of the senses exist and are real. Matter is the only thing denied to exist, most of mankind won't miss it.

36. What is taken away are corporeal substances, substance in the vulgar sense means a combination of sensible qualities remains. Substance in philosophical sense for something that supports accidents or qualities without the mind, we take it away even though it never existed even in the imagination.

38. It may be objected that it is odd to say that we eat and clothe ourselves in ideas, Berkeley agrees but says it is because it isn't common to use the word idea to signify the combination of sensible qualities, i.e. things. But that objection doesn't concern truth of the proposition. If one accepts that we eat and dress with the immediate objects of sense which cannot exist unperceived or without the mind then Berkeley will accept they are more properly called things.

39. However, Berkeley objects to the associations of "thing" that it is something that exists without the mind and that it is more general and includes spririts as well as ideas. He prefers "idea" because they exist in the mind and are inactive.

40. For those who assert they will beilieve their senses over any argument, Berkeley asserts his assurance and belief in the senses, and feels there aren't any principles more opposite to skepticism.

41. The second objection is between real fire and fire in one's imagination. Berkeley says it has already been addressed but adds that the pain caused by real fire is very different from the imaginary pain, but everybody will admit that real pain cannot be in an unperceiving thing without the mind.

42. Third objection - we perceive things to be at a distance from us and it seems absurd to say they are as close as our thoughts. Berkeley answers by pointing out we experience distance in dreams.

43. He refers us to a New Theory on Vision, about distance not being visible.

note on top of page reads,"Berkeley often believes words and language mislead us"

44. He refers to theory on vision again; asserts that visible sensations tell us what tangible ideas we will perceive, as intended by the author, so that we can excite this or that motion in our own bodies.

45. Fourth Objection - things are constantly being annhiliated and recreated. He asks if anything is meant by the existence of an idea apart from its being perceived, if one says yes Berkeley concedes, if no, then acknowledge it is unreasonable to defend he knows not what, that which has no meaning.

46. Berkeley says that many philosophers assert the same type of thing when they say that light and color are the only objects of sight and are sensations that no longer when not perceived and that the schoolmen do this as well since they argue that this universe demands God's continual creation to keep it existing.


48. The objection of 45 does not give us a problem since based on our principles what is required is for at least one mind to perceive the idea for it to exist.

49. Fifth objection - if extension and figure are modes (predicated of the subject where they exist) and attributes and they only exist in the mind then the mind is extended. Berkeley answers that they are in the mind as idea not as mode, and it doesn't follow that the mind is blue if blue only eixst in ? ? ? what philosophers say of subject and mode is ? ? ?. A die is nothing distinct from its ?, ?, and ?, dies does not denote a subject and substance beyond this.

50. Sixth objection - getting rid of of matter undermines all advances in the physical sciences since the sciences proceed on the supposition of matter. Answer - all phenomena are as easily explained without it by showing why we are affected by a particular idea on a particular occasion. It is how matter affects the spirit that is unexplainable.

51. Seventh objection - it seems absurd to take away natural causes and ascribe them to the operation of spirits. Fire doesn't heat, a spirit does, etc. Answer - we should think like the learned but talk like the vulgar, like we do with saying "the sunset".

52. Any phrase in vernacular that aids in our well-being by exciting appropriate sentiments, may stay. And this is inevitable anyway, so he encourages his readers to understand his sense from context making allowences for innacurate but inevitable modes of speech.

53. Some scholastics and some modern philosophers allow matter but claim God is the cause of all things. But he wonders why they would allow God to have created matter if it was useless and everything could have been done without it.

54. Eighth Objection - the widespread belief in matter. Answer - people can't believe in a contradiction and something meaningless, men sometimes believe in properties they've heard though they really have no meaning.

55. In addition, the prominence of a belief doesn't mean anything as is evident in the case of the motion of the earth.

56. But where did the belief originate? Answer - men experienced ideas that they knew they weren't the author of so they supposed them to exist independent of mind. Philosophers partially corrected this by saying the ideas of perception don't exist without the mind but they supposed objects existed independent of mind, and our ideas are resemblances of those, again, their idea was due to their knowing they weren't the author of the ideas.

57. Why suppose ideas resembled and caused by things in their likeness rather than ? ? They weren't aware of repugnancy of things like our ideas existing outside mind. Second, because God is not sensible ? human agents. Third, because God's operations are regular and uniform. People tend to think of God (a free spirit) when something out of the ordinary occurs, not when everything is regular. Especially when inconstancy and multibility in acting is seen as a mark of freedom.

58. Tenth Objection - that his philosophy is inconsistent with sound truths of philosophy and mathematics. For example, motion of the Earth, since it is an idea, if it isn't perceived, it is ? He believes that motion agrees with his tenents. That ? ? Earth moves or not is reduced to whether or not if we ? view it as moving if placed in space and viewed it more with the other planets, and that our evidence seems to suggest that is what we would view.

59. Berkeley thinks we can make sure and well grounded predictions, based on evidence, as to what we would perceive in various circumstances.

60. Eleventh Objection - why is there any need then for order in machines like watches or in animals? That exquisite art seems pointless, whereas in common philosophy assigns uses observes to explain abundance of phenomena.

61. Answer - first, his apriori proofs with utmost evidence are more convincing than that objection. Second, the objection faces a similar difficulty for why would God creat that elaborate machines if he could just will it. But for those who believe in those machines without mind have the problem of existing without purpose, since movement is caused by spirit.

62. The parts and machines aren't necessary to produce an effect but is necessary to produce things in a constant way according to laws of nature, learned by observation and are used by men to form artificial things and explaining phenomena, which only consists of showing consistency and uniformity. God could, if he willed, perform a miracle and make the watch keep time without the mechanics but if he acts according to rules of mechanism which he established for wise ends in the creation.

63. It is sometimes necessary for God to create a miracle but should seldom be used less they lose their convincing ? ? ? that it was an act of God, and God seems to prefer ? us of his attributes by the harmony and contrivance of nature that shows his wisdom and beneficence.

64. There is a certain order and connection between ideas, like cause and effect, and there are combinations of ideas behind the scenes producing the effect as it is seen on the theater of the world, only dicernable by the philosopher. But ideas cannot cause another to do anything so why does God creat all these ideas intricately related to one another to no purpose?

65. Answer - connection of ideas does not imply cause and effect but of a sign the sound I hear is not caused by the collision but it is the sign of it. Second, the reason ideas are formed into machines is the same reason for combining letters into words, to produce a great number of effects from a few ideas, made by rules, so that we perceive info about what to expect from an action.

66. The natural philosopher should search for the signs of the Author rather than searches for explanations of corporeal causes.

a note at the top of the page reads, "Berkeley definition of matter 67"

67. Twelth Objection - if one changes the definition of matter to an inert senseless substance that exists without the mind. Berkeley says it is as absurd to suppose a substance without accidents as accidents without a substance. Even if it is allowed to exist it would exist nowhere since it doesn't exist in the mind, and extension depends on the mind.

68. But the definition of matter here says it doesn't act, doesn't perceive, and isn't itself perceived, all those are negative except for the idea of it supporting so it supports nothing. They object that matter might be the unknown occasion which God uses to excite ideas ? but how can it be present if we cannot perceive it by sense ? ? ? it cant produce an idea in our mind, doesn't have their ? ? or extension, exists nowhere, so the words "to be" don't have their common meaning.

69. Occasion means the agent that produces an effect or something accompanies an effect. Matter doesn't make sense here because it doesn't cause anything and it is not perceived so it doesn't accompany anything.

70. But what if matter is only perceived by God that remind God what ideas to impress on our mind?

71. Answer - this changes the issue and asks whether or not there are ideas in God's mind that direct him to produce sensations in our mind like an orchestra does with notes from sheet music though those who hear the music are ignorant of the notes. But this seems to ? and doesn't object to our assertion that there is no sensless, unperceived substance.

72. Reason will show that our sensations show the goodness and wisdom of the Author spirit. The idea of an infinitely good, wise, powerful spirit is sufficient to explain Nature, but nothing perceived leads to the thought of matter and there is no phenomena or reason to suppose matter, nor does it mean anything.

73. There are reasons why men supposed the existence of matter. 1) They thought that color, figure, and motion existed outside of the midn so they needed a substratum where they could exist, since they couldn't be conceived to exist by themselves. Later they divided them into primary and secondary qualities the former existing without mind. The latter with the mind. But he says he has shown this to be false so there is no reason to believe in matter anymore and it is impossible if matter is to be an unthinking substratum of qualities and accidents existing without the mind.

74, 75. Reasons why we believe in matter without reason.

76. Perhaps one could call ideas in mind of God matter but anything of this name of unthinking substance, extension, ? other sensible qualities is impossible.

77. But what if there are qualities that exist in matter that we can't perceive? Why worry about matter or such qualities if they in no way concern us. What advantage is there in disputing about we know not what.

78. Even if we could perceive the qualities with a new sense we would have same reason against their existing in an unperceiving substance. Qualities are nothing else but idea which must exist in a mind.


83. The proper use of words is the marking of our conceptions, or things only as they are known or perceived by us. Our doctrine is therefore consistent with the right use of our language.

84. Miracles are not affected negatively. Moses's staff turning into a snake is not a deception of the senses, and neither was Jesus's turning water into wine, a snake is that. Wine is that idea.

85. Consequences of our doctrine

86. Human knowledge is reduced to 2 heads: 1) of ideas 2) of spirits. Berkeley explains origins of skepticism - 89.

87. rerum natura

89. Important

92. The notion of matter has been made use of by others

93. Description of materialists

94. The concept of matter contributed to idolatry.

95. It has caused problems for Christians liek the Socinians and their problems with the body of Christ.

97. Abstract ideas is another source of problems.

97. 98. Time problems and time defined

99. Abstraction of extension

100. Abstraction of happiness and virtue.

101. Skepticism has caused problems for natural philosophy.

102. One cause of skepticism is the belief that in the essence of each thing is the cause of its properties, recently attributed to mechanistic causes: figure, motion, weight, etc. which endeavor to explain in vain, like in the case where one idea is assigned the cause of another.

103. How are we enlightened by the mechanical principle of attraction? What is signified besides the effect itself?

104, 105. Philosophers don't have an exacter knowledge of phenomena than the commoner but only a larger comprehension of the harmonies of Nature, since spirit is the only cause of things, the philosopher recognizes likenesses, conformities, similarities not causes, which the philosopher reduces to general rules that allow us to make very probable conjectures and predictions.

106. We should be wary to not extend this knowledge into general theorems and pronounce universality and essential qualities. Berkeley cites the stars seeming fixed position to plants perpendicular growth, elasticity of the air as counter examples to gravitation. There is nothing essential or necessary in those things only the will of the governing spirit.

107. Philosophers entertain themselves in vain looking for natural causes distinct from spirit. Philosophers should think about the final causes of things since creation is workmanship of a wise and good agent. Pointing out the various ends to which things are adapted and why things were contrived is a good way of accounting for them and worth of a philosopher. With this system we should still observe Nature and perform experiments to enable us to draw general conclusions which is the result of God's kindness to us not of relations of things in themselves. By studying Laws of Nature we can demonstrate other phenomena.

108. Natural philosophers consider signs rather than causes since he can understand natural signs without saying a rule that so and so, and it is possible to extend analogies of rules of Nature too far and we will run into mistakes.

109. A wise man reading various books uses the particular sense to understand meaning rather than strict grammar similarly we should not reduce each phenomena to a general rule, instead we should exalt the mind with the beauty, order and variety of natural things, and make the parts of creation glorify God, as the ends they were designed for and the sustenations and comfort of living creatures.

110. Netwon's treatise on mechanics supposes time, space, and motion to have an existence without the mind, and are ordinarily conceived in relation to sensisible things though in their own nature there is no such relation.

111. Absolute time was dealt with in sec 97 and 98. Absolute space is supposed to be unperceivable to sense, it is itself similar and immovable. Relative space is moveable and is defined in respect to sensible bodies, is often mistaken for immovable space. Place is a part of space occupied by a body, and if the space is absolute or relative so is the place. Absolute motion is translation of body from absolute place to absolute place and similarly with relative motion except with relative place to relative place. Since we cannot perceive absolute space we try and define it in relation to bodies we regard as immovable. But we must abstract from our senses since we never know which body is at rest and which is in motion (in relation to one another) And one and the same body might be at the same time at relative rest and in relative motion. So that is why we should only consider the true and absolute which are distinguished from relatively all parts in absolute which preserve the same position with respect to the whole partake of the motions of the whole and the place being moved, that which is placed there in is also moved. So that a body moving in place that is in motion, participates in motion of its place and true motion is never generated or changed otherwise than a force impressed on the body itself. True motion is always changed by force impressed on the body moved. Last, in circular motion barely relative there is no centrifugal force which is proportional to the quantity of motion.

112. Berkeley says that to conceive motion there must be at least two conceived bodies where distance between them is changed, i.e. there can only be relative motion.

113. And only one might be moved and which is moved is determined by which the action is applied, and this is preferred rather than relative movement defined as change in distance from some other body because of how we use the word movement in ordinary life. As in walking down the street we don't say the stones move under my feet.

114. Absolute motion exclusive of all external relation is incomprehensible. Berkeley says he does not think the experiment to show that centrifugal force does not belong to circular relative motion shows that.

115. To denominate a body "moved" it must change distance in relation to another body and the force occasioning that change be applied to it. If we see a change in distance but no force we see apparent motion, which is a mistake on our part that something was in motion.

116. It follows that motion does not imply absolute space distinct from what is perceived by sense and related to bodies. We can't even form an idea of pure space without body. Berkeley says if he moves a part of his body freely he says there is space if he is restricted he says there is body. And in proportion to lesser or greated motion, space is more or less pure.

Ideas of space and distance are not obtained by vision.

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