The Invisible surface that Glows chapter 3

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The Invisible surface that Glows chapter 3

• Jane Patty Rath

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• What do you see?
• An old mans portrait?
• Two people on the sidewalk?
• A dog taking a nap?

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The idea of constructing objects

• Is that taking it too far?
• Are we constructing our phenomenal experience of
  the objects or are we constructing the object
  itself?
• Dr. Hoffman To experience is to construct, in
  each modality and without exception.

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Evidence for construction of visual objects

• 1) Subjective contours to create shape and
  enhance whiteness
• 2) Subjective surfaces accent contrast, black
  and white

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Questions

• Are we constructing the subjective triangles?
• And suppose we do, then are we just constructing
  that triangle alone, or even the black ink
  borders? Idealists say that we create even the
  black ink we see on our pages.

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• 1)You can construct borders without also
  constructing changes in brightness.

• 2)Conversely, you can construct changes in
  brightness without also constructing borders.

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Rules that didnt work

• Symmetry you create subjective figures only
  because we innately prefer symmetry
• Simultaneous brightness contrast when objects
  are views surrounded by a contrasting background,
  the background induces the images brightness.
  If so, then more black should lead to brighter
  whites

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Rule 11

• Construct subjective figures that occlude only if
  there are convex cusps.
• Cusps abrupt changes in slope
• 1)Convex cusps
• 2)Concave cusps

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Occlusion

• Key if there are convex cusps, then any
  subjective figure that you see will appear to
  occlude.
• Pacman vs. smooth square
• smoothed corners of the blobs look like they
  are pushed up against the corners of the square,
  not as if the subjective is occluding whats
  behind.

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Mathematical/logical proof of rule 11

• As we have seen from Chapter 2, rule 7 stated to
  interpret a T-junction as one rim occluding
  another.
• When the object in front becomes invisible, then
  the T-junction turns into convex cusps.
• With the T-junction turned convex cusps, the
  subjective figure would be constructed to
  occlude.

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Support ratio

• Even though these 2 squares have convex cusps
  and the same support ratio (which is the ratio of
  gap length to total length) but the square in the
  top is not as bright as the bottom.

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Nonaccidental relations

• These lines have the same curves so the
  probability of them being unrelated is low.
  Therefore we see black objects on white
  background and vice a versa.

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Rule 12

• If two visual structures have a nonaccidental
  relation, group them and assign them to a common
  origin.

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Rule 13

• If 3 or more curves intersect at a common point
  in an image, interpret them as intersecting at a
  common point in space.

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Magic squares

• According to rule 13, we would see the first 2
  squares because they do not have intersecting
  curves while in the last square they have three
  intersecting curves.

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The eye
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Rods and cones

• When you see a line, you are actually
  constructing the line because the rods and cones
  dont pick it up as a straight line.

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Pointillism, Georges Seurat

• Likewise, millions of dots are used by artist,
  Seurat, to come up with this masterpiece where
  we can see lines and objects.

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Eye ? LGN ? V1

• Our retina is only one step of the process of our
  perception. After retina finishes process of an
  image, it sends the results to a structure in the
  midbrain called the lateral geniculate nucleus,
  LGN. Finally, the results arrive at the primary
  visual cortex, V1.
• This process of physiology suggests that we do
  construct lines. Lines are first constructed in
  the V1.

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What causes what?

• Does the brain cause phenomenal consciousness? Or
• Does our phenomenal consciousness construct the
  brain?

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Stereo vision

• The stereo vision works because the image at our
  left eye is slightly different from the image at
  the right eye.
• Our visual intelligence uses the small
  disparities between the left and right eye
  images, and some trigonometry to construct shapes
  in 3D.

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Questions

• If this table is my construction, then why does
  everyone else see the same thing?
• How can we say that we are constructing, when we
  see the same object?
• How are we even sure that we do indeed see the
  same object?

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Argument from Consensus

• Premise we all see this table.
• Conclusion therefore, none of us constructs the
  table.
• This is an enthymeme, an argument with a hidden
  premise

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Premise we all see this table.Premise if we
all see X then none of us constructs X.

• Conclusion therefore, none of us constructs the
  table
• The premise of consensus is just false because we
  all see X and yet we all construct X.
• We all see the same things because we construct
  the same things. We all use the same rules of
  construction.

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Questions

• Granted that we construct everything we all see
  according to the same rules of construction
• What is it that is actually there for all of us
  to construct (and see) at the same time and
  place?

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If I construct the table that I see, then why
cant I push the table with my fist?

• Argument from Compliance
• Premise I cant put my fist through this table.
• Conclusion Therefore, I dont construct the
  table.
• This is another enthymeme.

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Argument from compliance

• Premise I want to put my fist through this
  table.
• Premise If I construct X, then X complies with
  my wishes.
• Premise I cant put my fist through this table.
• Conclusion Therefore, I dont construct this
  table.
• Because we construct according to rules, we cant
  do to them what you wish if what you wish
  violates the rules of construction.

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Subjective Necker Cube

• You construct the cube but you cant choose which
  cube you first see.