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THE VEIL OF PERCEPTION

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Martin Brown

on 10 May 2017

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Transcript of THE VEIL OF PERCEPTION

THE VEIL OF PERCEPTION
The perceiver only ever has access to the
representations
of a world as it truly is.

What is the NATURE of the external world?
It is impossible to know how accurate our subjective perceptions of the objective world are.

We cannot know for sure in what way our perceptions resemble the world as it truly is.

It is possible to doubt the EXISTENCE of an external world
Russell points out the "uncomfortable possibility" that there is no external world.

It may be that there is no real physical world of reality.

The trap of...
SOLIPSISM

The belief in an external world is an irrational superstition.

There is no external world.
There are no other people.
There are no other experiences other than your own.
Trying to convince others of the truth of solipsism is futile as their minds do not exist
Our perceptions of the world must be at least fairly accurate because...
Our senses have evolved in order to survive in the real world ...
The testimony of
others support our subjective experiences

Just because our perceptions enable us to survive does not
necessarily
mean they are at all accurate.

It is possible that in order to survive we need a distorted perception of reality.

Other animals survive yet perceive the world differently.
If all humans have a distorted perception of reality, the testimony of others only affirms the distortion. It does not reveal the world the way it really is.
It is possible that all humans are being deceived by Descartes' Demon, or are plugged into a Matrix wherein all our experiences are mere 'data' fed into our minds. Others testimony is as inaccurate as our own.
There is an external mind-independent reality because...
John Locke argues...
B. Russell
argues...

1. Lack of choice.
3. Practical.
'Best Hypothesis'
Physical objects continue
to exist even when not perceived.
"
If I turn my eyes at noon towards the sun, I cannot avoid the ideas which the light or sun produces in me
".

Whilst I can conjure the concept of heat and light in my mind, I cannot experience the sensations at will. Therefore, if humans cannot control the sensations they experience, it suggests that there is an external world which produces them in us.
Descartes agrees!
"
There is certainly further in me a certain
passive
faculty of perception, that is, of receiving and recognising the ideas of sensible things, but this would be useless to me (and I could in no way avail myself of it), if there were not either in me or in some other thing another active faculty capable of forming and producing these ideas. [...]
those ideas are often produced in me without my contributing
in anyway to the same, and often against my will[.] Hence we must allow that
corporeal things exist
".
Dreams!
Is not also true that whilst dreaming we have little control as to what we experience? The dream comes from within me, not externally, therefore, lack of choice does not necessarily entail existence of an external world.
Descartes' Demon
A lack of choice could also be explained by the existence of a deceptive being that gives us false experiences leading us to the incorrect conclusion that there is a mind-independent reality.
Locke argues that what is perceived in a dream is quite different to a veridical experience, which is far more vivid.
A man who dreams he is next to a furnace is aware that it is a different experience compared to putting his hand in an actual fire.

**This argument will not pursuade the sceptic who believes we are in an extended dream from which we are yet to awake**
2. Coherence of senses.
"
Our senses in many cases bear witness to the truth of each other's report concerning the existence of sensible things without us
".

Our senses, in the most part, provide us with a coherent understanding of an external world. Locke argues that as we can both see and feel a fire there must be an object that stimulates both senses. If ever I am of the opinion that a sense is being fooled I can use another one to test its veracity.
Dreams!
It is also true that whilst dreaming we may experience something through more than one sense, yet there is no external reality causing this experience.

I can dream of touching, seeing and tasting an apple without a sensible apple existing.
Descartes' Demon
The Cartesian demon could be tricking all of our senses. The combination and coherence of the sense-data makes the deception of an external reality all the more persuasive.
"[...]
finding that pleasure or pain follows upon the application of certain objects to us whose existence we perceive or dream that we perceive by our senses, this certainty is as great as our happiness or misery, beyond which we have no concernment to know or to be
".

Whilst it is perhaps impossible to absolutely prove the existence of a physical external reality, our well-being depends upon the presupposition that there is a mind-independent universe.
"
[...] our instinctive belief that there are objects corresponding to our sense-data ... does not lead to any difficulties, but on the contrary tends to simplify and systematise our account of our experiences, there seems no good reason for rejecting it
".


DREAMING
Our experiences are part of an extended dream from which we have and may never awake.
We are merely brains in vats being fed experiences which we believe to be real.
Our experiences are caused by a deceptive being, or we're plugged into
a 'Matrix'.
"[...]
the external world does really exist, and is not wholly dependent for its existence upon our continuing to perceive it
".
(B. Russell,
Problems of Philosophy,
Chapter 2)
BRAIN
IN A VAT
CARTESIAN
DEMON
REALISM
"
If the cat exists whether I see it or not, we can understand from our experience how it gets hungry between one meal and the next; but if it does not exist when I am not seeing it, it seems odd that appetite should grow during non-existence as fast as during existence. And if the cat consists of merely sense-data, it cannot be hungry, since no hunger but my own can be a sense-datum to me
".
(Russell, Problems, Ch. 2)
Our perceptions of the world can tell inform us of some
objective truths
about the external world of matter...

Locke argues...
Russell argues...
...relationships
...'Primary
qualities'

Temporal relations
Spatial relations
'Time' passing is relative to the perceiver; it can appear to pass quicker than at other occasions. However, we can know that the objects of perception occur in a particular order. It makes sense to talk of 'before' and 'after', just not the actual length of time.
Perceptual variation makes it hard to talk of actual distances. Space is hard to objectively quantify. However, the objects of perception can inform us of where real objects are in relation to each other. It is possible to have awareness of 'front', 'behind' and 'next to', just not the precise gap between.
Primary & Secondary qualities
The immediate object of perception can be separated into at least two qualities. Secondary qualities are mind-dependent, whereas primary qualities exist in the real object. Colour, smell and taste are secondary qualities caused by primary qualities such as extension and motion.
"
These I call original or primary qualities of body, which I think we may observe to produce simple ideas in us, viz. solidity, extension, figure, motion or rest, and number
".
"[...]
take a grain of wheat, divide it into two parts; each part has still solidity, extension, figure, and mobility: divide it again, and it retains still the same qualities; and so divide it on, till the parts become insensible; they must retain still each of them all those qualities
". (Locke, Essay II, viii, par 9)
"[...]
such qualities which in truth are nothing in the objects themselves, but powers to produce various sensations in us by their primary qualities, i.e. by the bulk, figure, texture, and motion of their insensible parts, as colour, sounds,
tastes, etc. these I call secondary qualities
".
(Locke, Essay II, viii, par 10)
"[...]
such qualities which in truth are nothing in the objects themselves, but powers to produce various sensations in us by their primary qualities, i.e. by the bulk, figure, texture, and motion of their insensible parts, as colour, sounds,
tastes, etc. these I call secondary qualities
".
(Locke, Essay II, viii, par 10)

Where has 'extension' gone?
Is 'solidity' the same as 'bulk'?
Why has 'texture' suddenly appeared?
Locke appears to be inconsistent with enumerating his primary qualities
Corpuscles
Locke, inspired by Boyle, believed the universe consisted of minute particles. Light, smells, and all physical things were made of tiny bodies of matter. These particles had motion, solidity, figure and extension (primary qualities) and caused in us the sensations of colour, taste and smell (secondary qualities)
Mathematical & Geometric
Primary qualities lend themselves to mathematical and geometric description. The position and size of an object compared to another can be precisely measured. It makes sense to talk of a hexagon being a six-sided shape. However, it makes no sense to divide and multiply tastes and colours in the same way we can with speed and mass.
Contemporary Science
Locke's corpuscular physics in a way is supported by modern science, which states that the universe is composed of imperceptible particles such as atoms and quarks, which have size and motion. The colours we perceive are merely lights waves (of electromagnetic radiation) of different lengths. Light is not coloured.
Essential properties
It is possible to conceive of objects, such as an apple, without certain qualities such as taste, smell or colour. However, there are some qualities that must remain for that object still to be conceived; the object needs extension, position in space, motion or rest.These intrinsic qualities are the primary qualities.
Multiple Senses
The primary qualities are accessible to more than one sense, for example, extension can obviously be known through both sight and touch. Secondary qualities, however, rely only one sense; colour through eyesight, smell through our nose. Though we may feel sound, it is actually the motion of particles that we sense.
Secondary qualities exist only in the mind
Berkeley argues all the qualities below are merely ideas in the mind and not real properties found in objects:

Heat
Taste
Smell
Sound
Colour

All subject to perceptual variation
Philonous
: Suppose now one of your hands hot, and the other cold, and that they are both at once put into the same vessel of water, in an intermediate state; will not the water seem cold to one hand, and warm to the other?

Hylas
: It will.

Philonous
: Out we not therefore by your principles to conclude, it is really both cold and warm at the same time, that is, according to your own concession, to believe an absurdity.
Philonous
: Inform me, Hylas. Is a sweet taste a particular kind of pleasure or pleasant sensation, or is it not?

Hylas
: It is.

Philonous
: And is bitterness some kind of uneasiness or pain?

Hylas
: I grant it.

Philonous
: If therefore sugar and wormwood are unthinking corporeal substances existing without the mind, how can sweetness and bitterness, that is, pleasure and pain, agree to them?
Philonous
: Can you perceive it possible that they [(odours)] should exist in an unperceiving thing?

Hylas
: I cannot.

Philonous
: Or can you imagine, that filth and ordure affect those brute animals that feed on them out of choice, with the same smells which we perceive in them?

Hylas
: By no means.

Philonous
: May we not therefore conclude of smells, as of the aforementioned qualities, that they cannot exist in any but a perceiving substance or mind?

Hylas
: I think so.
Hylas
: That they inhere not in the sonorous bodies, is plain from hence; because a bell struck in the exhausted receiver of an air-pump, sends forth no sound. The air therefore must be thought the subject of sound. [...] It is this very motion in the external air, that produces in the mind the sensation of sound.

Philonous
: What! is sound a sensation?

Hylas
: I tell you, as perceived by us, it is a particular sensation in the mind.

Philonous
: And can any sensation exist without the mind?

Hylas
: No certainly.
Philonous
: What! are the beautiful red and purple we see on yonder clouds, really in them? Or do you imagine they have in themselves any other form, than that of a dark mist or vapour?

Hylas
: I must own, Philonous, those colours are not really in the clouds as they seem to be at this distance. They are only apparent colours.

Primary qualities exist only in the mind
Berkeley challenges Locke and argues all the qualities below are merely ideas in the mind and not real properties found in objects:

figure
extension
solidity
Motion
Rest

All subject to perceptual variation
Philonous
: A mite therefore must be supposed to see his own foot, and things equal or even less than it, as bodies of considerable dimension; though at the same time they appear to you scare discernible, or at best as so many visible points.

Hylas
: I cannot deny it.

Philonous
: And to creatures less than a mite they will seem yet larger. [...] Can one and the same thing be at the same time in itself of different dimensions?

Hylas
: That is absurd to imagine.

Philonous
: Then as for solidity; either you do not mean a sensible quality by that word, and so it is beside our inquiry: or if you do, it must be either hardness or resistance. But both the one and the other are plainly relative to our senses: it being evident, that what seems hard to one animal, may appear soft to another, who hath greater force and firmness of limbs. Nor is it less plain, that the resistance I feel is not in the body.


Philonous
: And is it not possible ideas should succeed one another twice as fast in your mind, as they do in mine, or in that of some spirit of another kind.

Hylas
: I own it.

Philonous
: Consequently the same body may to another seem to perform its motion over any space in half the time it doth to you. And the same reasoning will hold as to any other proprtion: that is to say, according to your principles (since the motions perceived are both really in the object) it is possible one and the same body shall be really moved the same way at once, both very swift and very slow. How is this consistent either with common sense, or with what you just now granted?



There is no real primary & secondary distinction
Berkeley argues that in the mind you cannot separate the primary from the secondary qualities. When you perceive an object you cannot remove colour without also removing extension and figure. Therefore, if one is correct in saying colour is mind-dependent, it has to be conceded that so to is extension, motion etc.

Philonous
: But I think the point may be speedily decided. Without doubt you can tell, whether you are able to frame this or that idea. Now I am content to put our dispute on this issue. If you can frame in your thoughts a distinct abstract idea of motion or extension, divested of all those sensible modes, as swift and slow, great and small, round and square, and the like, which are acknowledged to exist only in the mind, I will yield the point you contend for. But if you cannot, it will be unreasonable on your side to insist any longer upon what you have no notion of.

Hylas
: To confess ingenuously, I cannot.

Philonous
: Since therefore it is impossible even for the mind to disunite the ideas of extension and motion from all the other sensible qualities, doth it not follow, that where the one exist there necessarily the other exist likewise?

Hylas
: It should seem so.

Philonous
: Consequently, the very same arguments which you admitted as conclusive against the Secondary qualities are, without any further application of force, against the Primary too. Besides, if you will trust your senses, is it not plain all sensible qualities co-exist, or to them appear as being in the same place? Do they ever represent a motion, or figure, as being divested of all other visible and tangible qualities?

The master argument
The idea that an object that exists independently of the mind is incoherent. Nothing can exist independently of the mind.
Try to conceive of a tree which exists outside of any mind - a tree which no one is aware of. As soon as you have done this, however, you are aware of the tree and it is not a tree which exists outside of a mind. Any thought of an object existing outside of a mind can only occur in someone's mind. Therefore, the idea of mind-independent objects is contradictory.
Hylas
: [...] What is more easy than to conceive a tree or house existing by itself, independent of, and unperceived by any mind whatsoever? I do at this present time conceive them existing after that manner.

Philonous
: How say you, Hylas, can you see a thing which is at the same time unseen?

Hylas
: No, that were a contradiction.

Philonous
: Is it not a contradiction to talk of conceiving a thing which is unconceived?

Hylas
: It is.

Philonous
: The tree of house therefore which you think of, is conceived by you.

Hylas
: How should it be otherwise?

Philonous
: And what is conceived is surely in the mind?

Hylas
: Without question, that which is conceived is in the mind.

Philonous
: How then came you to say, you conceived a house or tree existing independent and out of all minds, whatsoever?

Berkeley argues...
...esse est percipi
(To exist is to be perceived)
IDEALISM
The immediate objects of perception are mind-dependent objects. Berkeley rejects the idea that there is 'matter' which we perceive through our senses. Objects are merely clusters of 'ideas' or 'sense-data' such as smell, colour, position and size.
(Subjective Idealism)
Above and beyond 'A-Level'!
Illusions & hallucinations
Idealism cannot explain the difference between perceptual error and veridical perception. If reality is in the mind, and illusions or hallucinations are false perceptions in the mind, how are we to tell the difference? The Idealist does not have an external real world to show that an illusion or hallucination is taking place.
The continued existence of objects
What happens to objects when no one is perceiving them? If I put an apple in a drawer does it stop existing? Does the interior of an apple not exist until it is cut or bitten in to? Why does a cat become hungry when there is a gap between it being perceived?
Regularity of the universe
If there is not a material universe independent of my existence which causes my perceptions, why does it behave in such a regular and predictable fashion? When putting an apple in a drawer we expect it to be there when we reopen it, and so it is.
The trap of...
SOLIPSISM
The belief in an external world is an irrational superstition.

There is no external world.
There are no other people.
There are no other experiences other than your own.
Trying to convince others of the truth of solipsism is futile as their minds do not exist
GOD
God is an omnipresent perceiver of all that exists.

1. By constantly perceiving the universe God ensures that the existence of objects is continuous.

2. As a benevolent omniscient being, God's perceptions are ordered and provide regularity.

3. God is the origin and cause of our perceptions.
This is why we have no control or choice
over our perceptions.

Hylas
: Supposing you were annihilated, cannot you conceive it possible, that things perceivable by sense may still exist?

Philonous
: I can; but then it must be in another mind. When I deny sensible things an existence outside of the mind, I do not mean my mind in particular, but all minds. Now it is plain they have an existence exterior to my mind, since I find them by experience to be independent of it. There is therefore some other mind wherein they exist, during the intervals between the times of my perceiving them: as likewise they did before my birth, and would do after my supposed annihilation. And as the same is true with regard to all other finite created spirits; it necessarily follows, there is an omnipresent eternal Mind, which knows and comprehends all things, and exhibits thm to our view in such a manner, and according to such rules as he himself hath ordained, and are by us termed the Laws of Nature.
No objective space and time
As there is no physical matter we cannot share and observe the same space at the same time. If one person perceives a tree in a field in their mind, and another person perceives a tree in a field in their own mind, Idealism does not support the notion that they are observing the same tree in the same field. Realism does explain how and why we can observe the same object.
Can/should 'God' be used to play this vital role?
Some philosophers do not agree with Berkeley positing the existence of God in order to 'solve' the flaws in his Idealism.
The existence of a God is not agreed upon.
There is no independent reason to suppose that (1) God exists, or (2) plays Berkeley's role.

God is a mind. We cannot conceive of minds using our senses yet all we conceive is
through sense perception. It is, therefore, impossible to have a coherent
idea of God.
1. The existence of God, as a supreme intelligence, explains why perceived 'matter' behaves so orderly. The idea that a mindless substance 'behaves orderly' and causes our perception does not satisfactorily answer why it should do so.
2. Berkeley does not assume or create a God in order to solve problems in his theory. The existence of God is an inference supported by his arguments; he wanted to demonstrate God's existence.
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