Consider the differences

  Consider the differences, if any, between 'knowledge' proper, and mere 'opinion' or 'belief'. Which theory of how we acquire knowledge deals with the differences adequately - Descartes' or Locke's? Explain your answer. HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. Lecture Notes: Knowledge: Descartes Required Reading: Descartes, Rene, Meditations, 1 & 2. Topics and Discussion: We begin with Descartes arguments about the ‘method of doubt’, his reasons for doubting the senses, and his claim to be certain of his own existence. We will come to understand that Descartes’ views about ‘knowledge’ are known as ‘Rationalist’. This week we also look at Locke (see Lecture Notes for Locke), who we will see is opposed to Descartes understanding of human knowledge – Locke is known as an ‘Empiricist’. ! Rationalist: one who believes that the only knowledge that is certain and indubitable (un-doubtful), is the knowledge acquired through pure reasoning – without having to go out and observe anything empirically. Knowledge acquired through the senses, or observation, i.e. acquired empirically, is knowledge that is always open to doubt. Knowledge acquired through pure reason is not subject to doubt, and is known to be certain. ! Empiricist: one who believes that human knowledge can only be acquired through the senses: i.e. sight, smell, taste, touch and hearing. Knowledge can only be acquired by empirical observation of the world around us; and all knowledge supposedly only available through pure reason can, in one way or another, be attributed, or traced back, to sensory experience. TOPIC 1: Descartes ! DESCARTES: Meditations 1, 2: Foundations for knowledge, skepticism and the method of doubt. ! Med. 1: Descartes employs his METHOD OF DOUBT to examine which of his beliefs are subject to doubt, and those that are not. He thinks that he can thereby discover certain and secure foundations for human knowledge. ! He first examines knowledge he has gained through his senses, i.e. EMPIRICAL knowledge. But he finds that this knowledge is subject to doubt. He has two arguments for why we should doubt knowledge gained by the senses: ! THE DREAMING ARGUMENT: since we can never tell, when dreaming, that we are dreaming, we could at any other time also be dreaming. Knowledge gained by the senses cannot determine for us if we are dreaming or not since it would be the same either way. ! THE EVIL GENIUS ARGUMENT: It is possible that all of the information we assume to be gained by the senses could simply be transmitted to us by some kind of Evil Genius, who is simply deceiving us that there is an external world causing our sensations. ! Med. 2: Descartes argues that although his senses can deceive him, he can never be deceived that he does not exist, because as soon as he is able to think, he knows that he must HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. exist. This is Descartes’ famous Cogito Ergo Sum argument: “I think, therefore I am”. Even if he is being deceived, he must exist to be deceived. Descartes, MEDITATION I: ‘On what can be called into doubt’: ! p. 1. Descartes explains he is on a quest to discover a secure foundation for human knowledge. ! So, the way to do that, according to Descartes, is to suspend assent from all previous knowledge i.e. from all opinions that are “…not completely certain and indubitable.” (Descartes, p. 1) ! Nothing is to be allowed back to count as ‘knowledge’ proper (as opposed to mere ‘opinion’) if there is any reason to doubt it whatsoever. He doesn’t have to check each individual belief one by one – je just needs to look at types of beliefs. ! p.1 The first set of knowledge to be attacked is that gained via the senses. What kind of knowledge is that? Well, anything that you can know through sight, smell, taste, touch and hearing. You can know that you are wearing a red sweater, that you are in front of your computer, that your house is at number xyz on ABC street. And so on. All the kinds of things that can be known through observation. ! But Descartes claims that the senses have delivered false information, or have ‘deceived us’ all at least once – therefore, the information they deliver can never be trusted. Remember when you thought you saw, in the distance, a tower that looked round? But when you got closer, you saw that it was square – your senses deceived you into thinking the tower was round. If you hadn’t gone any closer, you would still think it is round. Now that’s not very ‘secure’ knowledge, is it? ! Descartes has TWO major arguments for why knowledge gained by the senses is unreliable: ! Dreaming Argument. ! Evil Genius Argument. Dreaming Arg: ! Descartes argues that he cannot be sure, nor can any of us, at any given moment, that we are not just dreaming, and therefore not experiencing the real world via the senses at all. After all, he reasons, everyone has had such realistic dreams that it was impossible to tell if, at the time, one was dreaming or really awake. So, this moment could be one such moment – we believe we are awake, but it may turn out that this was all a dream! ! Why does it show that information we gain by the senses is unreliable? HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. ! Descartes claims that he has no way of telling whether he is awake or asleep at any given time – do you agree with that? Are you convinced that you might be dreaming RIGHT NOW? Of course, in general there is a different ‘feel’ about dreaming versus being awake. But the point is that at any given moment we simply have no way of being absolutely certain that we are not now dreaming. ! He adds to this that (Descartes, p. 2) the thought that even though we might be dreaming, the things that appear in our dreams seem to be always made up out of the same sorts of things – so that we never seem to dream up completely new creatures. Some things, Descartes says, some universal and simple things, might not be open to doubt; whereas ‘composite’ things, or things made up out of the simple things are open to doubt: ! “For whether I am awake or asleep, two plus three make five, and a square has only four sides.” (p. 2) So, truths of math and geometry, at least, seem to be above suspicion since these do not appear to change whether we are asleep or awake. ! BUT: DESCARTES SAYS – HOW DO I KNOW THIS FOR SURE? It is only because I assume God does not want me to be deceived all the time that I believe this – what if there existed, not a supremely good God, but an Evil God ( or a ‘demon’ as Descartes calls it – we will call it an ‘Evil Genius’ to connect it with some modern thoughts about this kind of possible deception)? (Descartes, p. 3) Evil Genius arg: ! p. 3. Now, Descartes is going to consider the possibility that everything he counts as opinion or knowledge is false (so not just withholding his assent now). To combat believing things out of force of habit, he decides to “…turn his will in the opposite direction” – and pretend that everything he had previously thought to be true is false. ! SO: here Descartes is going to take all of his beliefs and opinions to be actually false, implanted in him somehow by an evil genius. ! A modern take on this idea is called the BRAIN-IN-A-VAT thought experiment. On this thought experiment, we imagine that, instead of us having a body and being here is this room, we are, unbeknownst to us, merely a brain suspended in some kind of nutritive liquid, with some number of electrodes attached to it, through which electrical impulses are sent, which cause us to perceive things as if we had a body, and were in this room right now. ! Anyone who has seen the Matrix or Total Recall will understand this possibility. How can we know for sure we are not just brains-in-vats, but embodied, moving, living agents? HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. ! Do you find this argument more convincing than the Dreaming Argument? Why/why not? ! How could one even being to argue against the idea that we might be brains-in-vats? Is there any way to prove this? WHO CAN SEE A PROBLEM WITH THESE ARGUMENTS? IS THERE ANY WAY TO REJECT THEM? ! One possibility is that although the senses SOMETIMES deceive us, it does not follow that therefore we should consider them to ALWAYS deceive us. ! For example, we might say to ourselves, we SOMETIMES make mistakes adding up. But that is not going to stop us from going shopping and knowing that MOST of the time we can add up just fine. Indeed, if we couldn’t add up, we couldn’t know that we had ever made a mistake. ! To conclude: Descartes arguments in Meditation 1 raise the possibility of what we call SKEPTICISM – about any knowledge gained via the senses; BUT ALSO about what the ‘external world’ (i.e. the world outside of our brains, that is supposed to be the cause of all of our perceptions) is like. It looks like a room with a view out on the trees and a garden, but in reality it is a laboratory, a large beaker, and a brain inside (and a crazy scientist messing with it!). The former is called EPISTEMOLOGICAL skepticism, and the latter is called ONTOLOGICAL skepticism (the first has to do with knowledge, the second has to do with what exists). Descartes, MEDITATION 2: ‘The Nature of the Mind, and how it is better known than the Body”: ! On p.4, Descartes claims he is going to continue with his meditations, even though his thought is in turmoil now. ! His plan is to treat all of his beliefs as false (or fictitious). He will now doubt everything he thinks he knows through the senses, including the idea that there is anything external to him, including that he has a body (for how do we find out that we have a body at all? We must see it or feel it, it is known to us via the senses). ! With all of this thrown into doubt, Descartes asks, “So, what remains true?” (p. 4) ! If he is able to doubt everything, and pretend it doesn’t exist – all of the material world, including his own body - he wonders if this means he can doubt that he exists as well? ! “No it does not follow (he says); for if I convinced myself of something then I certainly existed.” (p.4) HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. ! BUT: Descartes thinks, where do my thoughts and perceptions, even if they are false, come from? There must be something outside of me to put them there. What if all these thoughts I am having right now were simply implanted in me by the demon? ! But that would mean that there must at least be a mind to put the thoughts and perceptions into – indeed it must be my mind. ! He says – ‘I must at least be something to be deceived’. ! He says he can imagine himself without a body, but it is impossible to conceive of not having a mind – because to conceive is to have a mind. ! This seems right: can YOU try to imagine that you do not exist? But then who or what is doing the imagining? Maybe it is the Evil Genius putting these thought there? But then, the thing that the thoughts are put into must exist, and since YOU are having the thoughts, You must exist! ! So, concluded Descartes, “I am, I exist, must be true whenever I assert or think it.” (p.4) This is Descartes Cogito Ergo Sum argument, i.e. “I think, therefore I am”. ! ! But there is more business to be dealt with, for Descartes. OK, he thinks he can be certain that he exists – at least insofar as he is able to think. ! But, Descartes asks himself, what kind of thing am I? ! I cannot be certain that I have any of the properties I have attributed to being a ‘body’ i.e. extension, shape, size etc. It is still the case that I cannot be certain that I really have a body. ! On the other hand, even if I am dreaming or being deceived, I must be a thinking thing – a mind at the very least. All I can be certain of is that I exist insofar as I think, imagine, am deceived, dream, believe etc. All I can be certain of, as to what kind of think I am, is that I am a thing that thinks (“…mind or soul or intellect or reason.”) p. 5. ! So, he finally has a (very tiny) bit of knowledge of which he can be absolutely certain, and about which he cannot be deceived: that he thinks and that he exists. ! Now, how or by what means does Descartes know these things? He has already shown that knowledge gained via the senses is deceptive. So he can’t know that he exists or that he thinks via the senses. Indeed the way he has found out that he exists and he thinks is…by HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. thinking alone. He did not have to go out and do any observation with the senses: he has been sitting alone at the fire all this time. He did not have to do any empirical observation to know what he now knows – he arrived at that piece of knowledge by pure reasoning. ! And now we have an idea of the kind of knowledge Descartes is comparing ‘knowledge via the senses with’. He is comparing it to ‘knowledge by reason’. It seems that there are two ways of coming to have beliefs or knowledge: one is to see things (hear, taste, smell etc.) But the other is to reason things out. For example, some thing I can come to know just by using my powers of reasoning (e.g. LOGIC), where I do not have to go out into the world to observe things. ! The truths of logic and math are like this. Think about geometry. If I know that a square has 4 sides only, then I do not have to go out into the world and have a look at every square to check that they only have 4 sides. I can know that “All dogs are canine” without having to go out and inspect every single dog to check that it is canine. It seems that, for certain types of knowledge, as long as I know the meanings of the terms involved (and learning meaning might involve me having to use my senses), but once I know the meaning of the word, say, “Triangle” I will also know that all of them have three, and only three sides. ! On the other hand, knowledge gained via sense-perception is different. Certain truths like “I am wearing a red sweater today” cannot be know by reasoning from the armchair. One has to use sense-perception to find this out. Descartes claims his knowledge of his own body is only arrived at via sense-perception. ! He believes this because: he can imagine himself still existing without a body. That is, because if he thinks, he exists, he can imagine existing even if he is only a thinking, disembodied thing. BUT: he cannot even try to imagine himself existing without a mind, i.e. without thought (because to imagine is to think, and therefore to exist. So: can YOU imagine existing without a mind? It is impossible.) ! He says “…for while I know for sure that I exist, I know that everything relating to the nature of body …could be mere dreams.” (p. 5) ! We distinguish these two types of knowledge by calling them “Knowledge via the senses” and “Knowledge via reason”. ! We also call them “a priori” (ah pree ory) versus “a posteriori” (ah post eery ory”) truths. Knowledge gained via reason is known prior to anything gained via the senses; and knowledge gained via the senses is gained after (posterior) the use of the senses. ! Consider these two truths: “All bachelors are unmarried males” = a priori? Or a posteriori? HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. ! “All bachelors wear brown socks” = a priori? Or a posteriori? And so, Descartes concludes that he knows that he exists and that he thinks as a priori truths: by knowledge gained purely by reasoning about it. He simply can’t know for sure if he is anything more than this, i.e. if he has a body, because knowing that one has a body is known through the senses: it is a posteriori knowledge – and this knowledge can always be deceptive. In the final section of Meditation 2 PIECE OF WAX ARGUMENT: ! Descartes claims he cannot remove the idea of ‘body’ from his head: he still keeps returning to the thought that bodies really do exist externally to his mind. He certainly still believes in his own body. ! So, he wants to consider what it is that we do know about ‘body’, and more importantly how we know it. ! He tells a soty about a piece of wax. How do we perceive this object? We might say “One perceives the piece of wax through the senses. You can see its color, feel its hard waxy texture, you can smell its scent etc. You might think that your knowledge of the piece of wax is completely acquired through the senses. ! BUT, Descartes continues, what if we put that piece of wax near the fire, and it starts to melt. All of those properties that we thought we knew about the wax: its color, texture, smell, shape etc. disappear! As the wax melts, it becomes a liquid puddle on the table. Descartes asks: “Is it still the same wax?” ! Of course it is, he says. But then, we could know the piece of wax in some other way than via the senses, since everything about it that the senses delivered has disappeared, and yet we still say it is the same piece of wax. ! From this thought, Descartes claims that he knows about the wax, not through the senses, but through the mind alone. He says this is because we think we know that there are bodies external to our minds because we perceive them through the senses. But, he says, what is really going on is that we “see” a bunch of properties: colors, sounds, tastes….and we judge that there are real objects, including people, out there. But judging is a mental operation – and so, he says, we perceive what we call “the external world” through the mind. (p. 7) Descartes holds that he perceives, not with his eyes, but with his mind. ! So, once again, Descartes is much more certain that he has a mind than that he has a body: or that there are any other bodies out there in the external world (anything material). This is because he perceives his own thing by pure reason, and not through the senses. Anything perceived by the senses is still untrustworthy. The only knowledge that can be trusted is that gained via the mind alone. HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. ! NOTE: The way Descartes uses the idea of ‘imagination’ in these meditations is not like we do, i.e. as a purely mental operation. For Descartes, it is a kind of mixing and matching of sense-perceptions that one has already had. So it is not an operation of ‘pure reason’. ! So, conclusion is: I must be a thinking thing – since what I do know about myself I know through my mind, I might be deceived about having a body, but I cannot be deceived that I am thinking. ! What do you thin about this idea? Is Descartes right? That ‘I”, for each of us at least, must exist? ! Do you think that therefore Descartes is right, and we should distrust knowledge gained by observation? Is the only knowledge we can really trust that gained by reason? Like the deductive arguments we have looked at? ! Who can see a problem with these arguments? Is there any way to reject them? ! One possibility is that although the senses SOMETIMES deceive us, it does not follow that therefore we should consider them to ALWAYS deceive us. ! For example, we might say to ourselves, we SOMETIMES make mistakes adding up. But that is not going to stop us from going shopping and knowing that MOST of the time we can add up just fine. Indeed, if we couldn’t add up, we couldn’t know that we had ever made a mistake. TOPIC 2: Locke LOCKE: Empiricism versus Rationalism Ø Whereas DESCARTES is a RATIONALIST, LOCKE is an EMPIRICIST. Rationalism holds that the foundation for certain knowledge is gained through REASON not EXPERIENCE, that is through the exercise of knowledge that is gained not through the senses, or through observation, but is gained a priori, before any experience whatsoever. Ø Empiricism holds the opposite: that the foundation of all knowledge is experience and observation – knowledge gained via the senses. For the empiricist, there is no knowledge to be gained prior to that gained by the senses, and so there is no INNATE knowledge according to them, i.e. knowledge or the ability to gain knowledge before or independently of experience. Ø Locke argued against INNATE KNOWLEDGE: that babies or the mentally deficient do not seem to have the kind of ability to deductively reason, or to know the a priori truths of mathematics and logic that the rationalist would have us believe. Ø Locke argued that all knowledge is gained via the senses: from SIMPLE ideas, which are then combined to make more COMPLEX ideas Ø PRIMARY AND SECONDARY QUALITIES: Locke argued that some qualities are primary and exist “in the objects” independently of anyone ever perceiving the object; such as size, shape, number, mass, volume etc. On the other hand, many other qualities are only secondary. What this meant for Locke is that some qualities exist only in the perception or the perceiver, such as colors, sounds, tastes, and other sensory qualities. These qualities exist as HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. “powers” in objects (e.g. as “the power to cause a sensation of redness in me”), but an object is not, in itself, red – it merely has a particular textural surface, which light bends off from at a particular angle, and light itself is merely particles and waves and is also not itself colored. John Locke 1632-1704, British, also wrote a lot of political philosophy. The Essay was published in 1690, so LOCKE WOULD HAVE READ DESCARTES – and was, to a large extent, responding to him, and other Rationalists at the time. It is in this context we need to read Ø He says “The understanding is like the eye in this respect: it makes us see and perceive all other things, but doesn’t look in on itself.” (p. 1). Ø He notes that he is interested in finding out about what it is that marks the line between knowledge and opinion: because, he thinks, we certainly express our opinions with great assurance: so how are we to know which ones we ought to count as known. Ø Locke talks about “ideas or notions” – let us understand this as any of the content of the mind – i.e. any idea, thought, belief, image, hypothesis, perception – whatever is in the mind at all. Ø Here Locke puts forward his Empiricist thesis, that all knowledge is gained by the senses, through observation and experience, combined with reflection on them. Ø His theory of knowledge is like this: First we get basic sense impressions – like color, shape, size, number, then we put these together to form ideas of objects; then we get impressions of one event following another constantly, and we form the idea of causation; we see enough examples of things to abstract away from particular instances to generalize over things – e.g. we see enough cats and eventually classify them all as ‘feline’, we abstract out ideas of particular things having the same color, or shape etc., until we build up our entire repertoire of adult knowledge of the way the world is. Chpt 2: NO INNATE IDEAS Ø For the Rationalist, a priori knowledge is knowledge that is not arrived at empirically – not via experience or the senses. So it, or its potential is already had by all rational beings at birth: hence the thought that a priori knowledge is ‘innate’ to us. (recall Descartes’ view that this is the only knowledge that we could not be deceived about). Ø Remember what a priori knowledge is supposed to be? self-evident truths such as: Ø “For any x, it is either A or not-A” Ø “Nothing can be both red and green all over” Ø “It is impossible for the same thing to both be and not be” HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. Ø “2 and 2 is 4” Ø “A triangle has three sides” Ø “A square cannot be circular” Ø The Rationalist says that such a priori truths are not learned through experience or observation but are INNATE PRINCIPLES IN THE MIND THAT WE ARE BORN WITH. Ø The Empiricist rejects this possibility emphatically, and believes, rather, that we come into the world as a tabular rasa - a ‘blank slate’ which impressions are made upon by the external world through our senses. Ø Locke claims that he can shoe that all the knowledge that can be had by humanity can be gotten without the help of ‘innate knowledge or principles’ – namely he is going to argue, via experience. Ø We need to note that what this is, is a difference of opinion about the source of all knowledge: is all our knowledge acquired OR are we born with some kind of innate knowledge or principles or structures in the mind? Ø Then proceeds to refute each of the argument given for innate knowledge by the rationalist: 1. Universal Acceptance argument: Rationalist claims that a priori truths are accepted by everyone as soon as they hear them (and thus the truths must be innate). Locke argues this simply isn’t the case: he says many of the truths are not only not accepted by all of mankind, but many people have not ever even heard of them at all. Children and the (more politically correct) ‘mentally handicapped’ have no thought of them 2. The truths are supposed, somehow, to be ‘imprinted’ on the mind before birth – but if this is so, how can it be that so many people are totally unaware of their existence? How can something be in your mind without your being aware of it? Locke says “….if imprinting means anything it means making something to be perceived; to imprint anything on the mind without the mind’s perceiving it seems to me hardly intelligible” (p. 4). These problems can’t be ameliorated by saying: “Well it is not the actual knowledge that is innate – just the capacity to recognize a priori truths as true, that is innate”. To this Locke note that on that theory, every truth would count as innate: i.e. every truth that any human could come to assent to. Ø He goes on to examine some possible other ways the Rationalist may have intended to mean that some knowledge is innate: perhaps she meant “these are truths that will be recognized once a being comes to the full use of reason i.e. either by growing up or by not being mentally incapacitated.” Ø BUT: Locke complains, this wipes out the distinction between axioms (which are known self-evidently) and theorems (which have to be deduced from axioms by rational rules): HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. Ø EITHER a priori knowledge is of the former kind or the latter: if it is axiomatic, then problem is that not everyone accepts the truths, if it is knowledge of theorems then why is it that we have to use reason to arrive at a priori truths if they are supposed to be innate already? – this amounts, according to Locke to saying that “we need reason to allow a man to learn what he already knew”. Ø If we allow that a priori knowledge is supposed to be axiomatic i.e. assented to as soon as someone hears it – then the body of innate knowledge will grow out of all proportion and will include not only the so-called “analytic’ truths, but also truths of the ‘natural sciences’ such as “two bodies cannot be in the same place at the same time” etc. Self-evident propositions do not need to be understood as innate. Ø SECTION 21: Moreover, Locke argues: if the innate truths have to be proposed to a person before he or she can be said to assent to them, this proves that such knowledge is NOT innate, but has to be learned (through hearing it). Ø Locke’s view is that when such ideas are ‘proposed’ and then immediately assented to, they are in fact learned. Book II: on Ideas and how we get them. Ø We suppose the mind begins blank-like a white paper. Ideas get on it, according to Locke, by experience. READ SEC 2 “To this I answer….naturally have” = INTROSPECTION READ SEC 3: sense data i.e. a patch of red = a sense-datum Ø SEC 5-8: All our ideas from a) sensation and b) reflection Ø READ SEC 9: “mind is always thinking” – Criticism of Descartes. This is Descartes’ argument that thinking is essential to the mind – so that the mind cannot exist unless it is thinking. And that it is always thinking makes it possible to exist without the body. Ø To this Locke says: he is not always aware of himself as thinking, he doesn’t think he thinks when he sleeps, nor all the time that he is awake. He also argues that it cannot be argued that we are thinking even if unaware of it for, he argues that this would make thinking pointless: if we could be thinking and yet remain ignorant of what it was that we thought, makes thinking useless. Ø SO: this is against Descartes idea that the mind is an immaterial substance that is separable from having a body. Ø By Section 23: Locke argues: “When does a man begin to have ideas? I think the true answer is: when he first has some sensation. Ø Now we come to Locke’s positive thesis about the origin of the content of the mind: it is through sensation in the body that causes a perception in the mind. Ø Locke’s view is that we form ‘ideas’ through a mixture of sensation and reflection. HCC, Intro to Phil-1301, Dr. Sally Parker-Ryan. Ø Through sensation we acquire ‘simple’ ideas and we combine them in reflection to form ‘complex’ ideas. Simple and Complex ideas: Ø Simple ideas are the basic data of our sensations – a color patch, a sound, a simple taste or texture. These are the “sense-data” which we combine together to form more complex ideas of say, a three dimensional figure, a tree, a landscape, another person….. Ø p. 25: “Getting ideas is entirely passive”: we are sort of like recorders or like photographic film….. Ø PAGE 29: must distinguish ideas (in the mind) and their causes (outside of the mind). BUT “Most ideas (in the mind) are no more like a thing existing outside us than the names that stand for them are like the ideas themselves”. Ø We often mistake the external world as resembling the representations we have in our minds. But the external world is, according to Locke, very different to the picture we have in mind, because many of our sensations are only in the mind –they are caused by things in the external world, but they do not actually look like those things…. PRIMARY SECONDARY QUALITY DISTINCTION: Ø PRIMARY QUALITIES: quantity, shape, extension, “qualities of this kind are those a body does not lose, however much it alters, however much force is used on it, however much it is divided”. Ø SECONDARY QUALITIES: are powers in things to cause sensations in us. Secondary qualities are e.g. color, taste, sound, texture. Ø External bodies cause ideas in us by causally interacting with our sensory apparatus. Ø But the causes, or ‘causal powers’ in the external world do not ‘resemble’ at all, the qualities which we perceive in our mind’s eye. Ø So, the external world, as it exists externally to us, is very different to the way it appears to us in perception.