Week 7 - Perception The Problems of Philosophy

Week 7 11/11/19 Perception The Problems of philosophy In the search of certainty, it is natural to begin with our present experiences~ knowledge is to be derived from them The distinction between ‘appearance’ and ‘reality’, what things seem to be and what they actually are Looking at a table~ colour is not something that is inherent to the table, will appear different to different people and from different perspectives Can we trust what we see with the naked eye? Do we need to look at the table through a microscope to see its real texture? A given thing looks different in shape from every different point of view The ‘real’ shape is not what we see, it is inferred from what we see. Senses seem not to give us the truth about the table itself but about its appearance The real table is not the same as what we immediately experience by sight or touch or hearing but must be an inference from what is immediately known - Is there a real table at all? - If so, what sort of object can it be? When we see a colour, we have a sensation of the colour - Actual colour is a sense-datum Collection of physical objects is called ‘matter’ - Is there such thing as matter? - What is nature? Bishop Berkeley~ brought forward reasons for regarding the immediate object of our senses as not existing independently His dialogues undertake to prove that there is no such thing as matter at all and that the world consists of nothing but minds and their ideas Matter = something which is opposed to ‘mind’, something which we think of as occupying space and as radically incapable of any sort of though or consciousness Berkeley denies matter, does not deny the sense-data which we commonly take as signs of the existence of the table are really signs of the existence of some-thing independent of us - He does deny that this something is non-mental, that it is neither mind nor ideas entertained by some mind Must be something that still exists when we go out the room or shut our eyes (when we can’t see it) What the senses immediately tell us is not the truth about the object as it is apart from us, but only the truth about certain sense-data which, so far as we can see, depend upon the relations between us and the object What we see directly and feel is an ‘appearance’, which we believe to be a sign of some ‘reality’ behind But if the reality is not what appears, have we any means of knowing whether there is any reality at all? Philosophy has the power of asking questions which increase the interest of the world, and show the strangeness and wonder lying just below the surface even in the commonest things of daily life The Argument from Illusion • According to Awareness, we are sometimes perceptually aware of ordinary mind-independent objects in perceptual experience Week 7 11/11/19 • Awareness can come from veridical experiences~ cases in which one perceives an object for what is it • Can also come from illusory experiences • A white wall seen in yellow light can look yellow to one • Argument from illusion aims to show that we are never perceptually aware of ordinary objects • Since we are aware of something in perceptual experience, what we are aware of is a ‘nonordinary’ object Philosophy of Perception • • • • • • • - Phenomenology: perceptual experiences are paradigmatically conscious experiences~ there is something it is like to perceive There is an important sense in which scientific theories of perception do not really address the issues surrounding perceptual consciousness Epistemology: perception is the primary source of our knowledge of the world in which we live. A key consideration will be to develop a theory that both informs, and is informed by epistemological considerations Important theories to bear in mind when it comes to evaluating a theory of perception A philosophical theory that wears both of these hats adequately yet is inconsistent with scientific findings will not be of much value Theory of perception will claim certain things exist Three key principles: - The Common factor principle o Different experiences can be more or less correct or successful o Full successful cases of perception- cases in which an objects is seen and seen correctly or “as it is”- perception o Illusion refers to cases in which an object is seen but seen incorrectly or “as it is not”. Have to talk about subjects being under an illusion o Hallucination refers to cases in which it seems to the subject as though something is seen but where in fact nothing is seen o Perceptions, illusions and hallucinations have a “mental state or event” in common - The Common Factor Principle states that although there is a sense in which indistinguishable perceptions, illusions and hallucinations are different experiences, they nonetheless have a “mental state or event” in common o Concludes that we are aware of sense data in cases or veridical perception too - Brain activity alone can be strong enough for hallucinations to take place~ nature of experience somehow determined by the underlying brain activity? - The Phenomenal principle o There must actually be something pink, for example, of which I am aware if I am seeing something pink o Has the form of a conditional (if-then statement). In order for things to be in a certain way, then certain things must exist The Representational principle o Visual experiences are intentional and representational o Experiences are about something in the world- something other than itself or “beyond itself” o See them as representing the world in a certain way o For example, a map and a postcode with St. Pauls cathedral~ both representations o Difference in how they represent~ map represents it symbolically. Map tells us where cathedral is post card does not but tells us its shapes colours and surroundings Week 7 11/11/19 • • o The content of representation~ what the representation tells us o A representation can misinform~ tell us things are a certain way when they are not Sense datum theories o Sense datum theorist temped by Common Factor Principle o Casual considerations give us reason to think that brain activity of the right kind is all that is needed to create a sense of datum o Perceptions, hallucinations and illusions differ but there have a common awareness of sense data o Proposes to analyse visual experiences o The relationship of sensing needs to be understood in a nonperceptual way The time lag argument o Time lag argument does not involve two stages but simply operates with the Phenomenal principle and complies with a premise o Attempts to include all cases o For example, the distance of some stars is so large that by the time the light reaches our eyes they cease to exist o A case in which there appears to a subject to be something that possesses a particular sensible quality when the only suitable object no longer exists o All cases of visual experience are time lag cases and in all cases of visual experience we are aware of sense data