Epistemology: Perception

Define Perception and External World

-Perception: The process by which we become aware of the external world, through our senses, also referred to as sense experience.

-External world: everything that exists outside of an individuals mind, consists of physical objects (e.g: mountains, bodies, etc)

Define realism and anti-realism

-Realism: The belief that objects exist independently of our minds

-Anti-Realism: The belief that objects exist mind-dependently

Define and Explain Direct Realism

-The immediate objects of perception are mind independent objects and their properties

-Objects exists mind-independently in the external world

-Objects have all the properties we perceive them to have

-We perceive objects directly without mediate between the object and ourself

-Objects continue to exist, and retain all their properties, when they are not being perceived

-People support it because it is endorsed by common senses, and it is the least complex theory of perception

What is the Criticism from illusion

-When we are subject to an illusion we ‘perceive’ properties that aren’t actually there (for example, when in water, a straight pencil appears bent)

-This attacks the DR belief that the objects and properties of our perception are unmediated and true to the reality of the external world

-This does not seem to follow for illusions

What is the standard form of the Illusion criticism of direct realism

P1: When subject to an illusion an object appears to a perceived to have a particular property (for example, a pencil appears to be bent)

P2: The perceived is directly aware of this apparent property (for example, a bent looking pencil)

P3: But the object does not have this property in reality (for example, the real straw is not bent)

C1: So what the perceived is directly aware of (the bent straw) and what is real (the straight straw) are distinct

C2: So, direct realism is false, we do not perceive physical objects directly

How does Direct Realism respond to illusions

-This over-simplifies our perception

-They do not take into account relational properties

-Relational properties: properties an object has in virtue of its relationship to other things

-So, we do not directly perceive a bent pencil, but instead perceive a pencil that looks bent, or a pencil subject to the laws of refraction

-In reality this is what is actually there: a pencil subject to the laws of refraction

-Any object in water looks bent (this is a fact about refraction) so it is not a problem with our perception)

-Our perception matches what is there, and there is no problem from illusions

What is the criticism of Perceptual Variation

-Objects appear to have different properties when perceived in different conditions

-For example: A table can appear both dark brown and light brown at the same time depending on the lighting

-If several people are looking at the table at the same time, nobody would see the same distribution of colours

-Attacks: The idea that the objects we perceive are exactly how we perceive them all the time in the external world

What is the Standard form of Perceptual variation

-P1: Direct realism claims that mind-independent objects exist and possess all of the properties we perceive them to have

-P2: We appear to perceive mind independent objects to have properties which appear to be different for perceives at different times

-P3: These properties are incompatible properties (example: no object can be red, orange, and white all at the same time)

-C1: Therefore, if direct realism is true, mind-independent objects have incompatible properties

-P4: Mind-independent objects cannot have incompatible properties at the same time

-C2: Therefore, direct realism is false, objects do not have all the properties we perceive them to have

How does direct realism respond to Perceptual variation

-We can explain using science and common sense why objects will appear different depending on its relational properties (properties an object has in virtues of its relationships with other things)

-We may not perceive something precisely as it is, but we do perceive it directly.

Outline and Explain the Criticism of Hallucinations

OUTLINE:

• P1: Hallucinations occur when a person perceives something which doesn’t exist outside the mind

• P2: Hallucinations exists only in the mind

• P3: Hallucinations can be subjectively indistinguishable from veridical perceptions

• P4: But, if hallucinations and veridical perceptions are subjectively indistinguishable, then the person must be aware of the same thing in both cases

• C1: Therefore, what they are directly aware of during veridical perception must also be in the mind

• C2: Therefore, we perceive the world indirectly and direct realism is false

EXPLAIN:

• Hallucination: a sensory experience of something that is not actually present, perceived as real without corresponding external stimuli

• This is a problem for DR because it suggests that what we perceive does not accurately or directly reflect mind-independent objects and their properties in the eternal world (the entire basis of DR)

• OR: it suggests that Direct Realists would say that hallucinations are mind-independent and in the external world (this is illogical and would not be accepted by a rational being)

How does Direct Realism respond to the issue from Hallucinations

-The common kind claim in P3 is incorrect

-Hallucinations arise from different mental states and so people are not ‘aware of the same thing in both cases’

-Hallucinations and veridical perceptions are disjunctive

-In the moment one may not be able to distinguish them, but when in a clear mental state, one is able to separate the two experiences

Outline and Explain the Time Lag argument

OUTLINE:

• P1: The light from distant objects (such as the sun) takes time to reach our eyes

• P2: What we are seeing now may no longer exist

• C1: Therefore, what we are seeing and what is there are different

• P3: This is no less true for physical objects at any distance

• C2: Therefore, what we directly see are appearances and not mind-independent objects and there properties in the external world directly

• C3: Therefore, Direct Realism is false

EXPLAIN

• Time differences between what is there and what we perceive means that we are not truly directly perceiving objects but instead perceiving a delayed image of what it looked like in the past (however slight the difference)

• Example: it takes 8 minutes for light from th sun to reach our eyes, so we are not perceiving the sun directly, but instead perceiving the sun 8 minutes ago. If the sun magically disappeared, we would not know for 8 minutes

• We trust our perception to give us knowledge of the world, but if we see something that no longer exists or appears different to how it currently is in the external world, we are wrong

• This is an issue because it suggests we are not directly perceiving the current world as we are not perceiving the qualities of objects how they actually are in the moment in time we attempt to to perceive them.

How do Direct Realists respond to the issue of Time Lag

• Accept the time delay but claim that this does not prevent direct perception

• We are still directly perceiving an object, but simply perceiving it as it was in the past

• There is a difference between the process of perception with the object being perceived (we are not actively perceiving an object in the past, it just takes some time for us to be able to perceive an object)

• Accepts the criticism and believe it does not harm the theory

Define Indirect Realism

-The immediate objects of perception are mind-dependent objects that are caused by and represent mind-independent objects (sense data)

-The world is made up of material objects that occupy space, these objects posses independent properties

-We are immediately aware of how objects appear in our minds, not the objects itself as our perception is mediated by sense data

Define sense data and describe the differences between sense data and physical objects

DEFINITION

• Sense data are the immediate objects of our perception according to indirect realists. They are subjective, non-physical and mind-dependent, and are caused by and represent mind-independent physical objects in the physical world, but may not resemble physical objects

DIFFERENCES

• Sense Data:

  • Mind-dependent: subjective and relative to perceived

  • Transient: temporary and exist only when perceived

  • Private: accessible only to the perceiver

  • Infalliable: Cannot be subject to doubt

• Physical objects:

  • Mind-independent: objective and not relative to perceiver

  • Permanent: constant and exist regardless of being perceived Private

  • Public: accessible to all perceivers

  • Fallible: can be subject to doubt

Define Primary and Secondary Qualities

-Primary Qualities: Properties that are though to have a real existence independent of our minds (size, shape), they cannot be separated from the body and experience of these qualities resembles something within the object

-Secondary Qualities: Properties we perceived that do not exist in the objects themselves but depend on a mind being present (smell, taste colour), they are separable from the body and experience of these qualities represent nothing within the objects

How can you distinguish between Primary and Secondary Qualities

1:

• Primary qualities physically exist in the objects themselves and cannot be separated, they will still exits when not being perceived, however secondary qualities do not (example: you can imagine and apple without taste or smell, but you cannot imagine an apple that has not shape)

2:

• Primary qualities are measurable and can be lent geometrical or mathematical description, whereas secondary qualities cannot (example: positions of objects can be described using precise measurements such as height and shape, but secondary qualities are subjective and described using things such as sound or colour)

3:

• Physical objects interact with each other based on their primary qualities, the behaviour of an object cannot be changed based on secondary qualities (example: the collision of two apples relies on direct, mass and speed, the smell or taste of them cannot change this)

Define the veil of perception

-This is the idea that our perception of the external world is mediated by sense data

How does the veil of perception create scepticism about the nature of the external world

-What we perceive is only a representation of the world, if we accept the veil of perception

-If this is the case, then we cannot know how accurate that representation is to what is actually in the external world

-We cannot know that the representation we perceive at all resembles the external world in any way

-It goes against our instincts to say that we are unaware of the nature of the external world and therefore people are less likely to accept indirect realism

What two ways can indirect realism respond to scepticism about the nature of the external world

RESPONSE 1: We cannot know the true exact nature but we have a strong idea

• Sense data can tell us about relations between objects

• If one object is red and one is blue, in the true external world there must be a corresponding difference between the two objects

• Even though this may not directly translate to the true colours in the external world, we cannot understand that there is something different about the two colours (same if the two objects are the same colour)

RESPONSE 2: We can know the nature of physical objects

• We cannot understand know about the primary qualities of an object

• These qualities exist independently of our mind and cannot be separated from this object

• We are able to know the primary qualities of an object, because of this we can know the nature of an object

How does the veil of perception create scepticism about the existence of the external world

-If we are not directly aware of the external world and can only perceive it through the veil of perception, we can never even be sure that the external world exists

-Descartes adds that we simply could be floating in a vat with an evil demon controlling what we ‘perceive’ and causing us to believe there is an external world

What are the three responses to scepticism about the external world

RESPONSE 1: Occam’s razor

• The simplest explanation for what we experience is that there is an external world

• It is easier to assume that there is an actual external world causing our perception rather than an evil demon controlling what we perceive

• This correlates with our instincts and experiences (of two competing theories, the simpler explanation of an entity is to be preferred)

RESPONSE 2: Perception is involuntary

• We can choose to remember previous sense experiences, but we cannot chose to receive present experiences

• For example, during a sunrise we cannot avoid the ideas of light that the sun produces within us or choose instead to perceive darkness

• This means that there must be something causing these experiences.

RESPONSE 3: Coherence of the senses

• We can often have multiple different senses that produce the same ideas within us

• For example, we may smell smoke and doubt the existence of a fire, but if we also see fire and feel heat we are more convinced of the existence of a fire

• This cannot be a coincidence so there must be something causing these sense experiences

What is Cockburn’s coherence of the senses argument in standard form

• P1: Sense data does not resemble the object that causes it (light waves do not look like redness)

• P2: Data from one sense does not resemble that of another (the sound of waves is not like the blueness of waves)

• P3: We know from experience that data from the different senses coheres with each other in a consistent law-like way (the feel of an object is not like the look of it, but small changes in one are always followed by a corresponding change in the other)

• Therefore, one sense is arbitrary but several consistent senses together suggest that there i a real object causing the sensation in a consistent, law-like way

Outline and Explain Berkley’s likeness principle

OUTLINE:

• P1: My idea of , for example, a tree, has certain sensible utilities (green, tree shaped)

• P2: But these sensible qualities depend on the mind

• P3: Something invisible cannot resemble something visible

• P4: Ideas are fleeting and changing, whereas material objects are supposed to be permanent and unchanging

• C1: Therefore, anything outside the mind cannot have such qualities

• C2: Therefore, it follows that a supposed material object could not be like or resemble an idea of it

EXPLAIN:

• Sense data cannot accurately depict mind-independent physical objects in the external world because there are many opposing qualities between sense data and mind-independent objects

How can indirect realists respond to Berkeleys likeness principle

• Something can represent something without resembling it (flags, symbols etc)

• Therefore, just because sense data is different from mind-dependent physical objects, does not mean they cannot represent them, it simply means that they cannot resemble them

Define Idealism

-The immediate objects of perception are mind-dependent objects. These objects don’t represent reality, they are reality. There are no mind-dependent objects.

-Instead of an external world God causes our sense data

-Objects still exist when not being perceived as the object is still being perceived by God

-There is a difference however between imagining and assuming, objects do really exist but are just a collection of sense data

How does berkeley’s Idealism challenge IDR and primary qualities

-Primary qualities (Such as size) vary just as much with perception as secondary qualities do

-Example: ants view objects as different sizes to us

-Therefore, primary qualities must be just as mind-dependent as secondary qualities

-Therefore everything we perceive must only be in the mind

-Therefore, IDR is incorrect as there is not a mind-dependent external world that causes our sense data, and the theory of primary and secondary qualities is wrong

How does IDR respond to Berkley’s argument about primary qualities

-Berkley misunderstands the nature of secondary qualities

-IDR does not say that secondary qualities are only in the mind, but instead they are powers within objects to cause sensations

-Just because secondary qualities may be different does not mean they do not exist

-Example: temperature of water is real, it has to do with KE of water molecules

Outline and Explain Berkeley’s Master Argument

OUTLINE

• P1: We are unable to perceive a mind-independent object that is not being perceived by a mind

• P2: When we try to conceive of a non-perceive object, it is now being perceived

• C1: Therefore, a mind-independent object cannot exist outside of the mind

• C2: Therefore, all mind-independent objects are mind dependent

• C3: Therefore, there is no such thing as a mind-independent object

EXPLAIN:

• Everything being perceived is being perceived by a mind, therefore, they exist dependently on a mind

• Therefore, if something is not being conceived or perceived by a mind it cannot exist

• When thinking of an object that is not being perceived, your mind is then perceiving of it and so it is impossible to do so

How can IDR respond to Berkeleys master argument

-Berkeley confuses perception (being aware of an object through the senses) with conception (thinking of an idea)

-Just because you cannot conceive of something does not mean it does not exit