Perception as a source of knowledge

What is the definition of direct realism and what does this mean?

The immediate objects of perception are mind independent objects and their properties, we can perceive these properties directly without mediation. (Immediate perception)

There is a real world of real objects, which retain their properties without an observer, and we have a direct access to it in perception. (Physical objects are mind independent)

What is the definition of perception?

Perception is a general term referring to the use of the senses: seeing, hearing, tasting, touching and smelling (etc), by which through experience we apparently gain knowledge of the world around us.

What are the immediate objects of perception?

What we are aware of straight away.

What are the ultimate objects of perception?

What we perceive at the end of the process of perception.

What’s a realist view?

Objects and their properties exist independently of our minds.

What’s the strength of direct realism being more intuitive?

Direct realism matches our intuitions and is sometimes referred to as the ‘common sense view’ as we are direct realists in our day to day lives. Russell argues that we should accept these views unless they lead to inconsistency). It fits with how we experience our experiences.

Criticisms: this doesn’t prove or support the theory, other premises that have matched our intuition have turned out to be wrong.

What’s the strength of direct realism of the ‘avoidance of scepticism’?

Sceptical arguments (saying that the information we get from our senses might be supplied by another evil source) doesn’t work against direct realism as it states that we are learning about the objects first hand, rather than receiving information about them.

What’s a strength of direct realism being a simpler model?

Direct realism has fewer stages than indirect realism with simpler explanations, according to Ockhalms razor principle, therefore direct realism should be favoured as it gives an equally good explanation..

What’s the strength of direct realism relating to explanatory power?

Being aware of physical reality and its properties explains how we can perform practical actions.

What’s a strength about direct realism relating to agreements in pereception?

Direct realism explains how we can all agree on aspects of the world e.g the appearance of an object.

What’s the overarching criticism of direct realism?

It cannot explain perceptual effects.

What is verdical perception?

Veridica perception is accurate/ truthful perception.

What’s an illusion?

Illusion is the effect whereby we perceive an objects, but with a property it does not really have e.g seeing a stick bend in water.

What’s the issue of direct realism relating to illusions?

Our senses distort the true nature of reality so what we perceive isn’t the same as the material objects.

P1) When subject to an illusion an object appears to a perceived to have a particular property P2)The perceiver is directly aware of this apparent property P3)But the object doesn’t have this property in reality C1)So what the perceiver is directly aware of and what is real are distinct C2)So direct realism is false: we do not perceive physical objects directly. The property which is being perceived but is not really there is sense datum, in illusions, we see sense datum directly rather than physical objects

What’s the bigger argument from illusion?

P1) We perceive something having some property F. P2)When we perceive something as having some property F, then there is something that is F. P3)In an illusion, the physical object does not have the property F. P4)Therefore, in illusions, what has the property F is something mental, a sense-datum. P5)Therefore, in illusions, we see sense-data, and not physical objects, immediately. P6)Illusions can be subjectively indistinguishable from verdical perception. P7)Therefore, we see the same thing, namely sense-data, in both illusion and veridical perception. P8)Therefore, in all cases, sense-data, and not physical objects immediately. C)Therefore, direct realism is false.

What’s another response of direct realists to the issue of illusion?

Some of the properties that we perceive are relational properties while others are not (instead they are intrinsic. In this case, the pencil has the relational property of looking crooked (due to the medium of the water), however is not crooked due to its intrinsic property being straight. Objects don’t have to appear exactly how they are (relational properties don’t always match intrinsic properties), despite this, we are still directly perceiving physical objects and their properties and their is no sense data.

What’s a response to this issue?

The second premise may be incorrect, and the perceiver is not directly aware of anything distinct from the physical object. The perceiver is directly aware of the pencil but it appears bent due to the circumstance in which it’s being viewed, nothing is mediating between the pencil and perceiver, the pencil is just appearing differently.

What is are perceptual variation?

Perceptual variation is the effect whereby we perceive an objects as having different properties when experienced from different positions or under different conditions e.g the colour of the object dependent upon the amount or type of light.

What is the formal argument against direct realism from perceptual variation?

P1) There are variations in perception. P2)Our perception varies without corresponding changes in physical objects we perceive. P3)Therefore, the properties physical objects have and the properties they appear to have are no identical. P4)Therefore, what we are immediately aware of in pereception is not exactly the same as what exists independently of our minds. C)Therefore, we do not perceive physical objects directly.

What’s an example of a perceptual variation?

Russell’s table appears to be different colours from different point of views due to the way the light reflects off of its surface (and the shape appears to vary from different points of view). Therefore the table cannot be labelled to be one particular colour but instead is an appearance dependent on how the light falls onto it and the viewpoint of the perceiver, therefore the ‘real table is not immediately known to us at all, but must be an inference from what is immediately known’. In other words, direct realism is false and the immediate perception of objects are just sense data, do not perceive the real world directly.

What’s a counter argument and response and defence to Russels table?

The real colour of the table is that which it appears when it is viewed under’ normal lighting’. How do we determine this? Although we may perceive an object in a certain way, we tend to prefer/ privilege certain conditions, although an object may be viewed under different conditions by different perceives, these observers tend to come to the same conclusions about the dimensions of the object. Only due to prior knowledge.

What’s another response to Russels table?

Direct realism can claim that in perceiving physical objects, some of the properties we perceive are relational properties while others are not, objects may appear differently to perceivers. The colour of the table appears different due to the angle at which light reflects off of its surface. To determine the correct qualities of the table, we need to perceive it from normal conditions.

What is sense data?

Sense data are the immediate objects of perception, they are what we are directly aware of. It is how we learn about te mind independent objects in the world.

What are hallucinations?

Hallucination is the effect whereby we take ourselves to perceive a object, but there is no object at all.

What is the issue of direct realism regarding hallucinations (full argument)?

P1) Hallucinations occur when a person perceives something which doesn’t exist outside their mind. C1) So what they perceive, the hallucinations, exist only inside their mind. P2) Hallucinations can be subjectively indistinguishable from veridical perception P3)But if hallucinations and veridical perception are subjectively indistinguishable, then the person must be aware of the same thing in both cases. C2)So, from P1, P2 and P3, what they are directly aware of during veridical perception must also be in the mind. C3)Hence we perceive the world indirectly and direct realism is false.

What’s a summary of the issue of direct realism regarding hallucination?

we may not be able to distinguish hallucinations from perception when we are experiencing them, they may be subjectively indistinguishable. What we are always immediately aware of is sense datum.

What are responses to the issue of hallucinations?

We can identify when we are hallucinating due to out senses (e.g Macbeth not being able to hold his dagger), if we couldn’t subjectively distinguish them from veridical perception, we wouldn’t know that we had them. They are not causes the same as veridical reality (impact on a sense organ compared to a malfunction in the brain).

What’s time lag?

Time lag is the effect whereby we perceive an object as it was in the past (e.g we hear thunder after the lightening strike or see the sun as it was eight minutes ago.

What’s the issue of direct realism regarding time lag (full argument)?

P1) the light from distant objects (e.g the sun) takes time to reach our eyes. C1) So what we are seeing now may no longer exist. C2) So what we are seeing and what is there are different. P2) This is the same for any physical objects. C3) And so, what we directly see are appearances not physical objects and direct realism is false.

What’s a response to the issue of time lag?

All that follows from the above argument is that we perceive objects as they were, the direct realists can accept that there is a time lag in perception and argues that we are still directly perceiving physical objects, just not instantaneously. E.g we are still directly perceiving the sun as it were eight minutes ago.

What is indirect realism?

The immediate objects of perception are mind-dependent objects (senses-data) are caused by and represent mind-independent objects. Sense data are mind independent objects that are caused by and represent mind independent objects, they represent and allow us to infer the nature or reality.

What are strengths of indirect realism?

Indirect realism overcomes the perceptual variations as what we directly perceive is not always an accurate representation of reality.

What’s Locke’s primary and secondary quality distinction?

Primary qualities of an object gives us ideas that resemble (look like) the qualities in an object. These include: size, length breadth, height, shape, speed, position… They are: measurable, accessible to more than one sense, are essential, can be defined independently of an perceive…

Secondary qualities of an object give us ideas that represent (stand for) the qualities of the objects. These include: colour, taste, smell… They are: not measurable, accessible with only one sense, are not essential, must be defined independently terms of the perceiver…

What’s an example of Locke’s primary/ secondary quality distinction?

primary qualities are ‘utterly inseparable’ from an object (its parts must retain s0me primary qualities even if we cannot see them, if not, they would’t be material at all) and do not vanish like secondary qualities do.

P1) If you continually divide an object the parts must retain the primary qualities even when they are too small to be perceived.

C) Therefore primary qualities must exist mind independently.

What’s an examples of a secondary quality vanishing?

Colours are only visible in and change depending upon light. Secondary qualities depend on the primary qualities and require a mind to appear in (are not in the objects themselves). P1)When we pound an almond, we merely change the shape of its parts. P2)But the colour and taste of the almond also change. C)So, the change in colour and taste is caused by the changes in the shapes of the almonds parts.

P1)Certain qualities disappear if we block our sense organs. C)So these qualities depend on the senes organs and do not exist as perceived in reality.

What’s a third argument of Lockes?

What’s a critisism?

P1) Certain qualities disappear if we block our sense organs.

C) So these qualities depend on ur sense organs and do not exit as perceived in reality.

Criticisms: This argument doesn’t distinguish between primary and secondary qualities, e.g closing our eyes- both qualities will disappear.

What is the definition of scepticism and what is scepticism in this case?

Scepticism is the view that we cannot know a particular claim, in this case the claim that physical/ material objects exist.

What’s the issue with indirect realism about it leading to scepticism about the existence of mind-independent objects?

If we are only directly aware of our sense data (the veil of perception and the trap of solipsism) how can we know if our sense data (perception) is an accurate representation of reality or if material objects that cause our senses data actually exist. We cannot have knowledge about reality/ that material objects independent of our mind exist. Descartes Evil Demon scenario - our sense data could be caused by an external source.

What is solipsism?

Solipsism is the view that all we can be certain of is our own mind.

What is the veil of perception?

The intermediary between us and mind-independent objects which we cannot see past (we don’t have direct access to mind independent objects.

What’s Lockes argument again scepticism about the existence of mind-independent objects, from the involuntary nature of perception?

Locke argues that we are not in control of our sense data. Therefore, perception is not subject to our will and so it is not controlled by us, and therefore is produced in our mind by an external source.

What’s the response against scepticism of mind-independent objects- the argument from the coherence of various kinds of experience, as developed by Locke and Cockburn).

Our sense often cohere with and support each other suggesting that there is one external cause for them both e.g feeling and seeing fire. Cockburn notes that the way objects feel to our touch allow us to predict how it will look (e.g a dice) by association and that we can predict what we will perceive next (e.g writing with our eyes closed). to us as well as how the reports of senses are correlated through change following on from experiences

However, as Locke also notes, these are not deductively valid arguments, the inference goes beyond the evidence, for example this occurs while we’re dreaming however is not reality.

What are weaknesses to the coherence of various kinds of experiences?

Inferences go beyond evidence when we dream our sense experiences are not controlled by our will.

If physical objects don’t exist, we can’t explain…

Why sense data aren’t under our control like memory and imagination are, why we get the same information from different sense, why we can infer from perceptual experiences and the very complex interaction between our actions and perception.

What’s the third (Bertrand Russell’s) response (that the external world is the ‘best hypothesis’ to the issue of scepticism about the existence of mind-independent objects?

Although we cannot prove the existence of the external world, it is still reasonable to believe it as it explains why we have the sense data that we do, why they appear to us in regular and predictable ways and why multiple people receive similar (the same) sense data when perceiving the same object under the same conditions, despite sense data being private, the best explanation is that they are perceiving the same material object. Our intrinctive belief of a material reality corresponds with our sense data, we should only reject it if it appears to be incoherent.

Example: hiding an apple in a draw, if left few a few weeks will rot as. This is most probably due to the apple being a mind independent object and so continuing to exist and so decayed despite not being perceived (external world hypothesis). It is rational to accept this unless there is a reason not to.

Why does Russel reject the above argument about the external world being the best hypothesis and what is his new argument?

The argument assumes that there are other people, whom receive similar sense data, to assume this is assuming the existence of material objects (as people are material), therefore this doesn’t answer the question.

P1) Either physical objects exist and cause my sense data or physical objects do not exist nor causes my sense data. P2) We can’t claim either to be true or false. C)They are both hypothesis P3)The hypothesis that physical objects cause my sense data is better. C2)Therefore physical objects exist and cause my sense data.

What’s an example supporting Russels ‘best hypothesis’?

A cat appearing in different places (it’s either a physical object which has moved (better explanation) or an unexplained changed in sense data).

What is Berkeleys likeness principle and how does he justify it?

Berkeley’s likeness principe says that sense experiences can only be like other sense experiences.

Our senses of an object can vary while the object does not so how can the changing experience resemble the non changing object. It is meaningless to try and understand mental experiences in terms of things in the world which are not mental.

What’s the issue of indirect realism about ideas not being able to be like material objects (Berkeley)?

We cannot know the nature of mind-independent objects because mind-dependent ideas cannot be like mind-independent objects

Mind-dependent ideas can only be like other mind-dependent ideas, we cannot make good sense of the ideas that a sense experiences might resemble something that isn’t sensed (mind dependent ideas cannot be like mind-independent objects). This challenged Locke’s view that primary qualities of objects represent objects. It also suggests that if indirect realism is true we will never be able to know what objects in the real world are like.

What’s a response to Berkeley’s argument?

While we may not be able to identify the resemblance between sense experiences and physical/ material objects, it doesn’t mean that these resemblances cannot occur, Locke gives an example of shapes, it makes sense that our ideas of shapes correspond with real shapes in the real world.

Indirect realists could withdraw the claim that some of our ideas of objects are like the real qualities in the objects.