BERTRAND RUSSELL 18721970

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BERTRAND RUSSELL (1872-1970)
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APPEARANCE AND REALITY

• Here the distinction between appearance and
  reality concerns objects in the external world.
• Appearance is the way external world objects seem
  to perception. For instance, that a table looks
  brown and rectangular.
• Reality is the way external world objects are in
  themselves apart from perception. For instance,
  whether or not the table is brown and rectangular
  in itself apart from perception.

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THE ARTIST AND THE PHILOSOPHER

• Russell The painter is concerned with
  appearances, with how things appear to the eye.
  Capturing the appearance of light on the surface
  of objects was important to Impressionism.
• The philosopher wants to get beyond appearances
  to truth. The philosopher wants to know, if
  possible, what the truth is about things in
  themselves as they really are.

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SENSE DATA AND SENSATIONS I

• Sense datadf. The things that are immediately
  known in sensation. (Russell.) Sense data are
  the data of the five senses such things as
  colors, sounds, smells, hardnesses, roughnesses,
  and so on.
• Sensationdf. The experience of being
  immediately aware of sense data. (Russell.)
  The sensations are seeing, hearing, tasting,
  touching and smelling.

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SENSE DATA AND SENSATIONS II

• Russell Whenever we see a color, we have a
  sensation of the color, but the color itself is a
  sense-datum, not a sensation. The color is that
  of which we are immediately aware, and the
  awareness itself is the sensation.
• Thus, a color seen is a sense datum. The seeing
  of the color is a sensation.

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SENSE DATA AND SENSATIONS III

• Russell talks about sense data in terms of
  sensation, and sensation in terms of sense data.
  This sounds circular, but what Russell is saying
  is that sensations and sense data are correlated
  in experience.
• They are correlated in that you cant have one
  without the other. And since you cant have one
  without the other, you talk about one in relation
  to the other.

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SENSE DATA AND SENSATIONS IV

• Sensations are acts or events of perception, and
  sense data are those things of which we are aware
  in the relevant act of perception. Accordingly,
  the sense data-sensation correlation is necessary
  in that sensations do not occur apart from sense
  data that are sensed, and there are no sense data
  apart from the sensations of them.
• For instance, we are aware of the sense data of
  colors and shapes in the sensation of seeing.
  There is no seeing apart from colors seen, and
  there are no colors seen apart from the sensation
  of seeing them.

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SENSATIONS, SENSE DATA, AND KNOWLEDGE

• Our knowledge of external world objects comes
  through sensation.
• And what we can know about an external world
  object must be based on sense data.
• What we can know for certain about the reality of
  things apart from the sense data we are aware of
  in sensation is a very difficult question.

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WHAT CAN WE KNOW ABOUT A TABLE? COLOR

• When we perceive a common object like a table, we
  are aware of its color if it is monochromatic, or
  its colors if it is polychromatic.
• However, Russell says that there are problems
  with supposing that a table has a single color,
  such as brown, even if that is what common sense
  would say.

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THE TABLES COLOR I

• Color as a sense datum depends on light - no
  light, no color. We do not see color in the
  dark, and we do not see color when our eyelids
  are closed, so that they block light from
  reaching our eyes.
• What color or colors is seen depends in turn on
  the kind or kinds of light which strikes the
  table. For instance, seeing an object in
  sunlight is different from seeing it in
  incandescent light. Each of these in turn is
  different from seeing the object in florescent
  light.
• We can also speak of seeing an object in a
  combination of light from sources of these
  different kinds. And artificial light can come
  in different colors, not just white light of
  standard bulbs, but yellow, red, green, and so
  forth.

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THE TABLES COLOR II

• For Russell, you cannot talk about an objects
  color apart from the kind of light in which the
  object is seen.
• Not only is the kind of light essential to talk
  of color as a sense datum, but so is the level of
  intensity of the light, that is, how bright it
  is. Colors will appear lighter in stronger
  light, and darker in weaker light.
• Just as one cannot talk about color apart from
  kind of light, so one cannot talk of color apart
  from intensity of light.

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THE TABLES COLOR III

• Where the light source is in relation to the
  object is also important in determining the color
  or colors of the object seen.
• The location of the light source concerns its
  angle to and distance from the object. As a
  light source comes closer to the object, it
  becomes brighter, and so any color of the object
  becomes lighter. As a light source moves away
  from the object, it becomes dimmer, and so any
  color of the object becomes darker.
• As the angle of a light source changes in
  relation to an object, so will what is seen be
  affected by this change.

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THE TABLES COLOR IV

• What is seen by an observer of the table will
  depend on where the observer is in relation to
  the table. That is, it will depend on the
  percipients angle to and distance from the
  table.
• Because no two people can occupy the same place
  at the same time, and color depends on the
  position of the observer in relation to the
  table, Russell says that no two people can see
  exactly the same distribution of colors at the
  same time. They can see very similar things, but
  not the same thing.

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THE TABLES COLOR V

• Color will depend in turn on the state of the
  percipient. Certain diseases, such as jaundice,
  and condition of the eyes, such as astigmatism
  and color blindness, can affect what a person
  sees. In addition, what a person sees can be
  affected by drugs and alcohol.
• Color also depends on intervening media.
  Intervening mediadf. Things which come between
  the surface of the object and the organ of
  perception relevant to perceiving the object.
  Kinds of intervening media for for sight include
  sunglasses, smoke, haze, tinted glass, and rain.

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SUMMARY OF THINGS RELEVANT TO COLOR

• An objects color depends on the following
  things
• 1. The kind or kinds of light in which an object
  is seen.
• 2. The lights intensity.
• 3. The angle and distance of the light source
  from the object.
• 4. The location of the observer relative to the
  object.
• 5. The state of the observer of the object.
• 6. Intervening media.
• Artists, including painters and photographers,
  know these things. They are relevant as well to
  the philosopher, who wants to know what our
  sensations tell us about the objects of
  perception.

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RUSSELLS CONCLUSIONS ABOUT COLOR I

• Nothing definite can be meant by talking about
  the color of an object like a table.
• This is true even if common sense would regard it
  as having a single color.
• Color is not something which is inherent in the
  table. Instead, color depends on the factors
  surveyed.

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RUSSELLS CONCLUSIONS ABOUT COLOR II

• The same is true in talking about the color of
  parts of a table.
• This is because the same things said about the
  table as a whole can be said about its parts.
  That is, the color of a part of the table is
  subject to the conditions listed above as much as
  the whole of which the part is part. As such, it
  might appear differently to different people at
  the same time, and its appearance could change
  over time, relative to the same or to different
  individuals.
• And, where different parts of the table appear
  differently, there is no reason for regarding
  some of these parts as more really its color
  than others. All colors of the table are
  equally colors of the table.

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RUSSELLS CONCLUSIONS ABOUT COLOR III

• The color of an object breaks down into an
  Impressionistic array of different colors, each
  of which has as much right as any other to be
  considered truly a color of the object.

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RUSSELLS CONCLUSIONS ABOUT COLOR IV

• When, in common speech, we refer to the color of
  an object like a table, we are talking about how
  the object would look to a normal person from a
  certain distance in standard light.
• This is okay for ordinary language as a
  convenient term, but not for philosophy, where
  paying attention to the criticisms advanced
  forces us to see that we cant mean anything
  definite by the color of the table.

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THE TABLES TEXTURE I

• We are aware of an objects texture through
  either sight or touch. And the texture of an
  object can be different for these different
  senses. For instance, a table may look smooth to
  the eye but feel somewhat rough to the touch.
• Russell We cant say that one surface is more
  real than another, or more really the surface of
  the table, that is, one which is seen or one
  which is felt.

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THE TABLES TEXTURE II

• Under a microscope, any apparent smoothness of
  the table will break down into uneven surfaces.
  And we cant we say that a smooth surface seen in
  normal vision is more real than an uneven surface
  under magnification, or that it is more really
  the surface of the table.
• Each surface is equally real, and equally a
  perceived surface of the table. It is just that
  one surface is seen under magnification, and the
  other is not.

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THE TABLES TEXTURE III

• Texture will also depend on the state of the
  percipient the surface of an object can feel one
  way to normal fingers, another to fingers which
  are sensitive, or not normal due to something
  like a burn or an abrasion.
• Texture is also affected by intervening media,
  such as a source of magnification for sight, and
  such things as paper, gloves, and lotion for
  touch.
• What we feel when we touch an object like a table
  will depend on which body part is used, and how
  hard the body part is pressed against the surface
  of the object.

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THE TABLES SHAPE AND SIZE I

• Common sense supposes that an object like a table
  does not change its shape and size even though
  its shape changes due to the angle of perception
  at which it is viewed, and even though its size
  changes due to the distance from which it is
  viewed.
• But that is exactly what our senses tell us -
  that objects look different from different angles
  and distances. These differences of size and
  shape in perception would be noted by an artist
  who painted an object from different distances
  and points of view.

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THE TABLES SHAPE AND SIZE II

• Russell A given thing looks different in shape
  from different points of view. Here a table has
  the shape of a rectangle at A, a trapezoid at B,
  and a parallelogram at C. Three different people
  could be seeing the table as A, B, or C at the
  same time, but we do not think that the table in
  itself simultaneously has these different shapes.

             A
B
C                                     
D
 
 
   
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THE TABLES SHAPE AND SIZE III

• The edges of a table look straight to normal
  vision, but would be irregular when looked at
  under sufficient magnification. Thus a line
  looks straight to the eye as in A, and looks
  irregular under magnification, as in B.
• - -
  _ - _ - -_________________ - -
  _ _ - - - _ -
• A
  B

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THE TABLES SHAPE AND SIZE IV

• A table appears to be one size when see from one
  place, and another when seen from another. As we
  get closer to it, it appears larger in our visual
  field, and, as we move farther away from it, it
  gets progressively smaller in our visual field.

                  A
B
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THE TABLES SHAPE AND SIZE V

• However, even though it changes size in our
  visual field, we do not suppose that the table
  itself is changing size in accordance with the
  change in perception.
• And two different people could be seeing the same
  table at the same time from different distances.
  But we do not think that the table has
  simultaneously two different sizes.
• As we are acquainted with different sizes and
  shapes in perception, the real size and shape
  of the table must be inferred from what we see.

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WHAT DO THE SENSES TELL US?

• Russell The senses seem not to give us the
  truth about the table itself, but only about the
  appearance of the table.
• Russell The real table, if there is one, is not
  the same as what we immediately experience by
  sight or touch or hearing. The real table, if
  there is one, is not immediately known to us at
  all, but must be an inference from what is
  immediately known.
• Russell says that such considerations must make
  us, as philosophers, question the confidence
  which we once had in ordinary sense perception.

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SENSE DATA AND PHYSICAL OBJECTS I

• According to Russell, in sensation we are
  directly aware of sense data, not physical
  objects themselves, as common sense supposes.
• This is because of the relativity of perception.
  I can perceive different things about the table
  at different times, such as changes in color,
  shape and size, and different people can perceive
  different things at the same time, such as
  different colors, shapes, and sizes.
• And yet we think that the real table, as a
  physical object is stable, not so changeable as
  our sense data. And so the table cannot be
  equivalent to the sense data we are aware of in
  perceiving it.

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SENSE DATA AND PHYSICAL OBJECTS II

• What Russells analysis of the knowledge of an
  object like a table gained through the senses
  shows is that we can get no single, definite,
  unchanging set of information or data about the
  table.
• In addition, he says that sense data are private
  to each separate person in depending on or being
  properties of their minds. But an object like a
  table is a public, physical object, not something
  private to or specifically related to any
  individual mind.

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SENSE DATA AND PHYSICAL OBJECTS III

• For Russell, the sense data of which we are aware
  in perceiving a table can tell us nothing about
  any definite properties of the table, but at most
  can be said to be signs of something which causes
  the sensations.
• For Russell, sense data are signs of physical
  objects which cause them.
• However, the sense data which we associate with a
  physical object cannot tell us what the nature of
  the physical object is in itself.

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SENSE DATA AND PHYSICAL OBJECTS IV

• Sense data are what appear to us as perceivers,
  and are taken to be the signs of an independent
  reality in the form of a physical object. The
  physical object is a cause of the sense data.

are caused by sense data X a
physical object(s) are a sign of
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APPEARANCE AND REALITY

• The real table must be something different from
  what we are aware of in perception, since our
  perceptions of the same thing vary.
• But if the reality of a physical object is not
  the same as its appearance to us as perceivers,
  then there are two questions 1) Can we know for
  sure that there is a mind-independent reality?
  strong version of skepticism about the external
  world and 2) If so, can we know anything about
  it, can we know what it is like? That is, does it
  in any way resemble our perceptions of it, or is
  it totally different? weak version of skepticism
  about the external world

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THE POWER OF PHILOSOPHY

• Russell Philosophy, if it cannot answer so many
  questions as we could wish, has at least 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.
• And showing us this strangeness and wonder, and
  making us reflect on them, is part of the value
  of philosophy.