1. Metaphysics in Early Modern Philosophy

2. The Atomic Theory of Matter The atomic theory poses a challenge to theories of substances or objects Atomic theory: things are composed of atoms; properties of things depend on nature and motion of atoms Things are not as they appear

3. Appearance and Reality Aristotle: objects cause perceptions, and are represented in them Causes of perception = objects of perception Atomic Theory: No— –causes are the atoms— which are real –objects are appearances

4. Causes and Effects Causes of perception are the atoms We don’t see atoms, but their effects What we see doesn’t exist in reality How can we distinguish the aspects of the effects (appearances) that do match the causes?

5. Primary Qualities Descartes: We perceive clearly and distinctly only the mathematical properties of objects: size, shape, motion Only they reflect the true natures of things

6. Primary Qualities Locke: Primary qualities are inseparable from objects; atoms have them Primary qualities are those objects possess according to the atomic theory of matter They produce simple ideas in us that resemble the primary qualities in the objects

7. Secondary Qualities Secondary qualities are effects of objects on our nervous systems They produce ideas in us that do NOT resemble them

8. Secondary Qualities Secondary qualities depend on primary qualities Secondary qualities are response- dependent: to have one is just to produce a certain effect in a perceiver

9. Primary and Secondary Primary qualities: mathematical properties, assigned to atoms by physical theory— e.g., size, shape, mass, motion Secondary qualities: effects of primary qualities on us— e.g., color, texture, moral and aesthetic qualities To be red is just to look red to a standard perceiver in standard conditions

10. Real and Nominal Essence Aristotle and Aquinas identify: –The essence of x = the properties necessary to x –The quiddity of x = the definition of x in re –The nature of x = what makes x what it is Locke: nominal essence = quiddity: uses secondary qualities Real essence = nature: real internal constitution

11. Real and Nominal Essence Gold –Nominal essence: heavy yellow metal –Real essence: element with atomic number 79 Water –Nominal essence: colorless, tasteless liquid (at common temperatures) necessary to life –Real essence: H 2 O

12. Locke’s Philosophy of Mind Idea Appearance This is a triangle Understanding Perception Thing in itself Abstraction

13. Real Essences Aristotle and Aquinas: We know objects by grasping their essences Locke: Which essence? –Nominal: concept; conditioned –Real: real internal constitution; unconditioned We study cognition as we study anything else We know real essences through scientific method

14. Idealist Critique We know world only through sense organs So, we know objects only insofar as they become internal objects They are objects of consciousness, constituted by consciousness We know objects only as conditioned by consciousness

15. Argument for Idealism We have reason to believe that something exists only if we can know it We can know an object only by making it an object of consciousness Any object of consciousness is conditioned by consciousness Anything conditioned by consciousness is mind-dependent So, we have reason to believe that a thing exists only if it is mind-dependent

16. George Berkeley (1685-1753) Idealism best defense of common sense against skepticism Descartes’s and Locke’s ideas of objects make no sense Attack on primary qualities and on substance

17. Against Primary Qualities We have no basis for thinking any of our ideas corresponds to some mind-independent reality We cannot judge resemblance to reality Perceptions of width, height, etc., vary while objects remain unchanged

18. Esse est Percipi We have access only to what is before the mind A thing can exist only if it is perceived Do things go out of existence when we aren’t looking at them? No— because God keeps an eye on them for us

19. David Hume (1711-1776)

20. True of all objects Example: Heraclitus: can’t step in same river twice

21. True of all objects The ship of Theseus Plutarch: “The ship wherein Theseus and the youth of Athens returned [from Crete] had thirty oars, and was preserved by the Athenians down even to the time of Demetrius Phalereus, for they took away the old planks as they decayed, putting in new and stronger timber in their place, insomuch that this ship became a standing example among the philosophers, for the logical question of things that grow; one side holding that the ship remained the same, and the other contending that it was not the same.”

22. Successions “... the objects, which are variable or interrupted, and yet are suppos'd to continue the same, are such only as consist of a succession of parts, connected together by resemblance, contiguity, or causation.... all objects, to which we ascribe identity, without observing their invariableness and uninterruptedness, are such as consist of a succession of related objects.”

23. Fictitious Identity “The identity, which we ascribe to the mind of man, is only a fictitious one....”

24. Imposed Identity Mental states link to other mental states: memory, intention, desire, similarities We construct the idea of self Self is not a unified thing— best compared to a commonwealth Questions about identity aren’t about the world, but about language

25. Verbal Disputes “... all the nice and subtle questions concerning personal identity can never possibly be decided, and are to be regarded rather as grammatical than as philosophical difficulties.... as the relations, and the easiness of the transition may diminish by insensible degrees, we have no just standard, by which we can decide any dispute concerning the time, when they acquire or lose a title to the name of identity. All the disputes concerning the identity of connected objects are merely verbal....”