PY3102 Handout 2:  Moore’s open-question argument:

 

These questions take the form “Is (Are) X(s) Y(s)?”  The “is” involved is the “is” of identity, not the “is” of predication.  A question is open if see it as meaningful to answer this question in the negative.  If a question is not open, then it is closed. 

 

Closed Questions:

 

(C1) If it is closed question whether Xs are Ys, then “X” has the same meaning as “Y.”  [This a conceptual claim about which definitions are equivalent.]

 

(C2) If “X” means the same thing as “Y,” then the properties they refer to- being an X or being a Y- are identical.  [This is an ontological claim about what is identical to what.]

 

Test case:

 

Are bachelors (just) unmarried men?

 

Let X=bachelor

Let Y=unmarried man

 

  1. It is not an open question whether bachelors are unmarried men. (Purported Fact)
  2. If it is closed question whether Xs are Ys, then “X” has the same meaning as “Y.”
  3. Therefore, “BACHELOR” has the same meaning as “UNMARRIED MAN.” (From 1 and 2)
  4. If “X” means the same thing as “Y,” then the properties they refer to- being an X or being a Y- are identical.
  5. Therefore, being a bachelor is identical to being an unmarried man.  (From 3 and 4)

 

 

To show C1 is false, you must show that there a case where it is not an open question whether Xs are Ys, but where “X” clearly has a different meaning from “Y.”

 

To show C2 is false, you must show that there is a case where two words have the same meaning, but refer to two different things, or sets of things. 

 

 

Open Questions

 

 

(C3) If it is an open question whether Xs are Y, then “X” does not have the same meaning as “Y.” [Conceptual Claim]

 

(C4) If “X” does not mean the same thing as “Y,” then the things they refer to- the property of being an X and the property of being a Y- are not identical.  [Ontological Claim.]

 

 

 

Test case:

 

Are beautiful paintings (just) paintings that produce pleasure in us?

 

Let X= beautiful painting

Let Y=painting that produces pleasure in us

 

 

  1. It is an open-question whether beautiful paintings are paintings that produce pleasure in us. (Purported Fact)
  2. If it is an open question whether Xs are Y, then “X” does not have the same meaning as “Y.”  (C3)
  3. Therefore, “BEAUTIFUL PAINTING” does not have the same meaning as “PAINTING THAT PRODUCES PLEASURE IN US” (From 1 and 2))
  4. If “X” does not mean the same thing as “Y,” then the things they refer to- the property of being an X and the property of being a Y- are not identical.  (C4)
  5. Therefore, being a beautiful painting is not identical to (the same thing as) being a painting that produces pleasure in us.  (From 4 and 5)

 

 

To show C1 is false, you need to find a case where it is an open-question whether Xs are Ys, but where X and Y still mean the same thing.

 

            There may be an ambiguity here.  Consider two interpretations of "meaning the same thing:”

 

1. According to the first interpretation, two sentences "mean the same thing" if they express the very same thought, involving all the same ideas.

2.According to the second interpretation, two sentences "mean the same thing" if they talk about the same objects and ascribe the same properties to them.

 

To show C2 is false, you need to find a case where words or expressions have different meanings, but refer to the same things.

 

            Morning Star =Evening Star

            Water =H2O