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A Level philosophy flash cards - Epistemology. Includes perception, scepticism, reason as a source of knowledge, defining knowledge.
Direct Realism
The theory of perception that we perceive mind-independent objects, directly and unmediated.
What is Realism in perception?
The theory that what we perceive are objects that exist mind-independent, in reality.
What is meant by ‘naive realism?’
Referring to direct realism, suggesting that it is overly-simplistic and more scepticism should be applied.
What 3 phenomena can be used to criticise direct realism?
illusions
hallucinations
time-lag
What is the argument from illusion and what aspect of direct realism does it criticise?
With illusions, the images we perceive do not accurately reflect the true and normal state of the object. It suggests perception is not direct because there is something mediating perception that changes the image.
What is the argument from hallucination and what aspect of direct realism does it criticise?
When we hallucinate, we are perceiving something that does not exist in reality. It criticises realism as hallucinations are mind-dependent.
What is the time-lag argument and what aspect of direct realism does it criticise?
The things we perceive are not in real time, because the speed of light slightly delays the images we see. This criticises the direct aspect of direct realism because it suggests that our perception is affected by the speed of light, mediating it.
What is veridical perception?
Accurate perception (not hallucinations etc.)
Which contribution did Russell make to criticisms of Direct Realism and what other theory does this support?
Perceptual Variation, supports Indirect Realism
What is the argument from perceptual variation?
When 2 people look at the same object, they see 2 different images based on their position in relation to the object. This suggests that there is some mediation that causes an object to appear different to each person, so perception is indirect.
What defence do direct realists use against perceptual variation?
Relational Properties
What are relational properties?
There are 2 types of properties: physical and relational. Relational properties are the properties that objects have in relation to other objects. You still directly perceive these properties, but these properties are mind-dependent (whereas the physical properties are mind-independent and intrinsic to the object.)
What is Indirect Realism?
The theory of perception that we perceive real, mind-independent objects, but this perception is mediated by sense-data.
What is a criticism of the perceptual variation argument?
With close observation, we can always find the true form of an object, what we perceive is accurate, even if you have limited information about the object. Therefore, differences in perception does not mean we perceive different things or that perception is mediated.
Which kinds of properties does direct realists distinguish between in defence of the perceptual variation problem?
physical properties, e.g. the sweet is red. These properties are objects always have.
relational properties, e.g. the sweet is tasty. These properties objects have only in relation to something else.
Relational properties are still directly perceived and of mind-independent objects, but their properties might be mind-dependent.
What are Locke’s primary qualities? Example?
qualities found in the object itself, these qualities are in the object regardless of whether they are being perceived. A part of the object.
Density, madd, motion, position
What are Locke’s secondary qualities? Example?
qualities which are not in the object themselves but the ‘power’ objects have to produce qualities on our minds when perceived. They are the power an object has to produce sensations.
Yellow, small, texture, sound
What are the 3 differences between Locke’s primary and secondary qualities?
primary qualities are scientific/measurable/quantifiable. You can measure objective facts to do with the object but not the subjective sensations they produce
primary qualities are essential - without these qualities, it cannot be the same object, whereas an apple is still an apple if you lose your sense of smell
primary qualities are accessible to more than one sense. Secondary qualities are single-sense qualities.
What example does Locke use to illustrate the importance of primary qualities?
The grain of wheat - no matter how many times you divide up a grain of wheat, it will retain its primary qualities. However, it may lose its ability to produce sensations in the perceiver.
How does Locke use his primary and secondary qualities to show Indirect realism is true?
He argues our objects probably exist MI because we perceive their primary qualities, but because secondary qualities vary between people, they must be MD. Therefore, perception of secondary qualities is indirect and IR must be true.
What is Locke’s term for what we actually perceive?
‘ideas’
What analogy does Russell use to support indirect realism?
Cinema Screen
When we perceive, it’s as if we’re watching a scene through a cinema screen. We are never perceiving a scene as it actually occurs. Everything we perceive is mediated as is through a cinema screen.
What is Russell’s term for what we actually perceive?
‘sense data’
How does Russell describe indirect realism through sense data?
He argued we can use our physical sense organs to gain information about external objects, from which the brain produces sense data. This sense data is what we perceive directly, not objects themselves, therefore, idealism is true.
How might indirect realism lead to scepticism and which idea supports this?
Because we only perceive sense data and not the MI objects themselves, how can we ever know they really exist? Therefore, IR leads to scepticism about realism. This is supported by the idea of the veil of perception.
What is Locke’s defence against scepticism?
He points out there is a difference between perceiving objects and imagining them. If objects weren’t real, we would be making them up and perception should feel the same as imagining, yet it doesn’t. It makes more sense that there are external objects that force these perceptions and they are involuntary rather than voluntary.
What is Trotter-Cockburn’s defence against scepticism?
Trotter-Cockburn argues that because the senses are coherent (i.e. seeing fire corresponds with smelling fire, feeling heat, etc.) This suggests that there is one external cause of perceptions (external objects) that causes all of these perceptions to happen at the same time.
What is Russell’s defence against scepticism?
Russell argues that the existence of external objects is simply the best hypothesis. Either they exist or they don’t, and we cannot prove either. therefore, they are both hypotheses, and the idea that they do exist is better. Therefore, we can say that external objects probably do exist.
What kind of reason does Russell’s best hypothesis defence involve?
abductive reasoning
Why does Berkeley argue that Indirect Realism is false?
IR cannot make any claims about the nature of MI objects because they are too different to what we perceive. Therefore, we cannot know what we perceive is really like.
Which analogy could be used to highlight Berkeley’s issue with Indirect realism?
Claiming that we can know about external objects from our perceptions is like saying that ‘Timmy looks like his uncle’ whilst only being familiar with Timmy and never having looked at his uncle.
What is Berkeley’s argument about all qualities that supports his idealism?
All qualities (including primary qualities like mass/motion/solidity) are subject to perceptual variation and are all mind-dependent. For example, a small man seems smaller to a big man than to an equally small man. Therefore, one object appears different in its primary qualities to different people.
what Latin phrase does Berkeley use to support idealism?
‘esse est percipi’ - to be is to be perceived. This suggests that because we do not perceive external objects directly, they do not exist.
What does Berkeley’s master argument aim to do?
prove that we cannot know of mind independent objects, therefore we cannot say that realism is true.
Outline Berkeley’s master argument
try to conceive of a tree which exists independent of any mind
in doing this, the tree is conceived by you and becomes dependent on your mind.
Conclusion: therefore the tree cannot be said to be mind-independent and nor can any object you can conceive of.
Which errors can Berkeley be said to have made in his master argument?
conflating the ideas of perceiving and conceiving - something can be conceived without becoming mind-dependent, but not perceived.
conflating the mental act of conceiving something with the thing being conceived - the mental act is mind-dependent, but the thing is not. (Russell)
If Berkeley’s argument was valid, it would lead to solipsism and incredible scepticism, could even lead refute his ideas about God. If our minds can only possess conceived ideas, and the mind is not an idea, our minds cannot possess the idea of God’s mind.
How can the idea of illusions and hallucinations criticise Berkeley’s idealism?
Idealism says that what we perceive is the reality of the world, and everything that normally exists is dependent on the mind.
Common sense says that illusions and hallucinations do indeed depend of the mind, and this is understood to be the difference between hallucinations/illusions and reality. If this distinction does not exist, are supposed to accept that all these kinds of perception are the same?
How does Berkeley respond to he criticism of hallucinations and illusions?
Berkeley claims that perceptions of illusions do not make us mistaken about what we perceive, but illusions lead us to make false inferences about what we will perceive next (when the illusion ceases.) E.g. if a refracted pencil looks crooked, it is actually crooked, but it misleads us to believe that when we touch the pencil, it will feel crooked (which it will not.)
Furthermore, we can use our understanding of the regularity and consistency of our usual perceptions to understand the unusual and misleading (yet not false) nature of illusions and hallucinations.
How can idealism lead to solipsism?
If we say that all that exists are the ideas we perceive, and other minds are not ideas, then we cannot perceive other minds. Like external objects, we should therefore treat other minds as non-existent.
How can Berkeley’s idealism respond to the issue of solipsism?
Berkeley could claim the objection ignores the role of God in his theory. Berkeley doesn’t claim that everything that exists can only exist in my mind, but it must exist in some mind. This does not rule out the possibility that other minds do indeed exist inside God’s mind (and God’s mind is the only one capable of possessing the concepts of all minds.)
However, this raises the issue of how we can have ideas of even God’s mind, to which Berkeley would respond by saying that it may not be an idea, but a notion or an intuition.
What are the issues with the role played by God in Berkeley’s idealism?
Berkeley’s appeal to God is not a better explanation of our experience than matter because of hallucinations and illusions.
God is not a deceiver, so he should not give us perceptions that result in us being misled.
Furthermore, if God is supremely perfect, then how can he give us sense data that is related to pain, surely he cannot experience pain himself. If God perceives all that everyone perceives, he would have to perceive all of the negative things in existence too.
How would Berkeley respond to claims that God cannot cause our perception of pain?
Berkeley claims that while God knows what it is for us to suffer pain, he does not suffer it himself. Human suffering is physical and in accordance with humanity and the physical laws of nature. God is not human nor does he have a body or align with physical laws, so he cannot suffer.
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