[4.2.4.] Evaluating the Platonic Argument.

 

Is this a sound argument? This breaks down into two distinct questions:

I. Is it valid?

II. Are the premises all true?

 

 

(I) Is the Platonic Argument valid? We can get clearer on whether this argument is valid by looking at its form:

 

1)      Either (a) or (b).

2)      If (a), then (c).

3)      If (b), then (d).

4)      Therefore, either (c) or (d). [supposed to follow from 1, 2 and 3]

5)      Not (c).

6)      Therefore, (d). [supposed to follow from 4 and 5]

 

There are two distinct “steps” or inferences in this argument:

·         from 1, 2 and 3 to 4 (premises 1, 2 and 3 are supposed to imply line 4)

·         from 4 and 5 to 6 (premises 4 and 5 are supposed to imply line 6)

 

If both steps are valid, then the entire argument is valid. Are both steps valid?

 

In fact, both steps of the Platonic Argument are valid, so the entire argument is valid. If there is anything wrong with the argument, it must be that one of its premises is false.

 

(II) Does the Platonic Argument have true premises? What we need to consider is whether lines 1, 2, 3 and 5 are true (lines 4 and 6 are conclusions that definitely follow from the other premises; i.e., if 1, 2, 3 and 5 are true, then 4 and 6 have to be true as well). So: are premises 1, 2, 3, and 5 true?

 

At the very least, this argument shows that there is potentially a serious problem with DCT. If DCT is to be salvaged, there must be some way of “going between the horns of the dilemma.” In other words, there must be some way of accepting DCT without having to accept that God’s commands are morally arbitrary and without giving up the doctrine of the goodness of God. In order to do this, you must be able to give good reasons for thinking that premises 1, 2, 3 and/or 5 are false.

 

 

Stopping point for Wednesday September 9. For next time, read all of RTD ch.11 (Don Marquis, “Why Abortion is Immoral”) and study today’s lecture notes. You may have a pop quiz over one or both at the beginning of the next class.