PHIL 301 Exam 2

Koslicki’s three arguments for realism about natural kinds

• The argument from induction and prediction

• The argument from laws of nature

• The argument from causal explanation

Mills’s objection to the view that race is a natural kind

• P1. If X is a natural kind, then any instance or member of X could not exist without being X

• P2. A member of a race can exist without being a member of that race

• C. Race is not a natural kind

Examples of ontological disagreement

• Universals exist/Universals do not exist

• God is/God is not

• Giraffes exist/Giraffes do not exist

Plato’s Beard

• P1. If "Pegasus is not” is true, then

  • It says something, and

  • The name “Pegasus” does not refer to or name anything

• P2. If the name “Pegasus” does not refer to or name anything, then the sentence “Pegasus is not” is nonsense, or fails to say anything

• C1. “Pegasus is not” is false (not true)

• C2. Pegasus is

Quine’s response to Plato’s Beard

• Quine claims that this response to Plato’s Beard is a “confusion”. His point is deceptively simple: anyone who asserts that Pegasus is not, or that Pegasus doesn’t exist, is not trying to deny existence to any idea. To introduce ideas is to change the subject

Quine on universals

• Skeptical of universals

• Math is the real universal

• Now let us turn to the ontological problem of universals: the question whether there are such entities as attributes, relations, classes, numbers, functions. (p. 48)

• Note that when Quine mentions functions, he has in mind the functions of mathematics. Mathematics, as we will see, plays an important role for Quine, because it is the only source of universals that he is willing to acknowledge.

Examples of tropes

• The specific shade of red

• The specific shape

• Mass or weight

Heil’s objection to tropes as parts

• P1. If X is part of Y, then X can exist without the rest of Y existing

• P2. The color of a thing (like a chair) cannot exist without the rest of the thing existing

• C. The color of a thing is not part of that thing

A-series

• Every moment in time is either past, present, or future

• The present, or noe, is where we are (privileged present)

• Time flows: what moment is present is always changing

• There are various asymmetries between the past and future

  • Metaphysical asymmetries: the past is fixed, but the future (at least if we reject determinism) is not fixed. We can, through our actions, change the future, not the past

  • Epistemic asymmetries: memory only reaches into the past, not into the future

  • Moral asymmetries: regret is an attitude we have toward past events; anticipation is directed only toward future events

B-series

• Every moment in time is either earlier than or later than any other moment in time

• There is no privileged present

• There is no flow of time

• There are no past-future asymmetries, but there may be an asymmetry in the direction of time

Part 1 of McT’s Argument

• P1. If there is time, then there is change

• P2. If there is no A-series, then there is no change

• C1. If there is no A-series, then there is no time

Part 2 of McT’s Argument

• P3. If there is an A-series, then every event is exactly one of past, present, or future

• P4. If there is an A-series, then every event is all three of past, present, and future

• C2. There is no A-series

Modifying prefixes

Prior observes that if we prefix such claims with certain further linguistic constructions, the result blocks, or nullifies any ontological commitment.

The argument from tense logic

• P1. We are ontological committed only to those things whose existence is entailed by our best theories

• P2. Tense logic is our best theory of tense and time

• P3. Tense logic entails the existence of present things, but not to past or future things

• C. We are ontologically committed only to present things, not to past or future things.