Berkeley’s idealism

• Berkeley's idealism


  The central claim is that all that exists are minds and their ideas. Physical objects do not exist independently of being perceived.
• Berkeley's idealism


  • Berkeley argues that the universe is sustained in existence through being perceived by the infinite mind of God
  • God directly causes our ideas or sense data
• Finite human minds


  Receive perceptions directly from God
• Perceptions in different minds

  Are sufficiently similar and cohere with each other such that there is the appearance of us perceiving the same objects
• Primary qualities


  Qualities that are said to resemble the objective properties of objects according to Locke
• Secondary qualities


  Qualities that do not resemble what causes them according to Locke
• Berkeley tries to collapse the primary/secondary distinction to show that neither primary nor secondary qualities can be said to resemble anything beyond the mind
• Locke argued that primary qualities are essential to an object
• Berkeley argues that we are equally incapable of conceiving of an object without secondary qualities and therefore that these too must be essential to our idea of it
• Berkeley's argument


  1. P1: It is impossible to imagine an object with only the primary qualities of shape, size, movement, etc.

  2. C1: So our ideas of the so-called secondary qualities of an object cannot be separated from those of its primary qualities.

  3. C2: It follows that they must exist together.

  4. P2: Indirect realists accept that our ideas of secondary qualities are mind-dependent.

  5. C3: It follows that our ideas of primary qualities are also mind-dependent.
• Locke is saying that secondary qualities themselves are mind-dependent, rather than that they are the powers in objects to cause sensations in us which are mind-independent
• The fact that both the primary and secondary qualities as perceived by me seem inseparable doesn't mean that both sets of qualities themselves must exist in the mind
• Rather, the sense data of primary and of secondary qualities exist in the mind, but the qualities themselves exist mind-independently
• Locke used the perceptual variation argument to show that certain perceived qualities cannot exist in material objects as we perceive them
• Berkeley tries to run a parallel argument for the primary qualities arguing that size, shape, and movement are also subject to perceptual relativity and so cannot be considered as real properties of external objects
• Berkeley's perceptual variation arguments

  1. P1: The perceived shape of an object changes depending on the angle of observation

  2. P2: An object cannot have different shapes at the same time

  3. C: Therefore shape cannot be a property of material objects

  4. P1: The speed of an object may appear fast or slow to different minds

  5. P2: But the motion of an external object cannot be both fast and slow at the same time

  6. C: So the motion is not a property of external objects
• Berkeley's conclusion is that the primary qualities are mind-dependent just like the secondary qualities
• The indirect realist can resist Berkeley's use of perceptual variation to try to show that there are no mind-independent qualities of objects
• The first two premises of Berkeley's arguments can be accepted, but it doesn't follow that the qualities themselves which indirect realists claim cause our ideas cannot be mind-independent
• Indirect realist response


  1. P1: The apparent size, shape or motion of an object varies

  2. P2: A material object's objective properties cannot vary

  3. C: Therefore the apparent size, shape and motion cannot be objective properties of material objects. But a material object can still have some specific size, shape and motion independent of the mind.
• Berkeley's 'master' argument


  Tries to show that the very idea of a mind-independent material object is contradictory and so impossible
• Berkeley's 'master' argument


  1. P1: Try to conceive of a tree which exists independent of any mind

  2. P2: In doing so, the tree is being conceived by you

  3. C: Therefore the tree is in your mind and not independent of any mind after all.
• A standard objection to Berkeley's 'master' argument is that it confuses the mental act of conceiving a thing with the thing being conceived
• It is true that my idea of a tree must be in my mind, but it doesn't follow that what my idea is about, namely the tree itself, must be in my mind