j*******7
发帖数: 6300 | 1 这个讲的比较简明扼要 --
http://www.randyeverist.com/2012/01/modal-ontological-argument.
The Modal Ontological Argument
What’s wrong with the ontological argument? That’s something I’ve been
wondering. Now of course, as is the case with every theistic argument we
give a generic name, the “ontological” argument is a type of theistic
argument. I only intend to focus on Plantinga’s modal ontological argument
(MOA). The MOA appears like this:
1. It is possible that a maximally great being exists.
2. If it is possible that a maximally great being exists, then a maximally
great being exists in some possible world.
3. If a maximally great being exists in some possible world, then it exists
in every possible world.
4. If it exists in every possible world, then it exists in the actual world.
5. Therefore, a maximally great being exists.
Many people dismiss this argument, thinking it’s some kind of parlor trick.
However, it is an excellent example of modal reasoning. First, let us
explain the argument and how the logic works.
A maximally great being is defined to be a being possessing maximal
excellence, “where maximal excellence entails such excellent-making
properties as omniscience, omnipotence and moral perfection.”[1] By (1),
Plantinga means to say such an idea involves no incoherence, and is
intuitively possible. That is, it really could be the case such a maximally
great being exists. Most people would agree with this. The second premise
just explicates the idea of possibility in a format called “possible worlds
.” A possible world is a complete description of the way reality could be,
down to the last detail, encompassing every proposition’s truth or
falsehood in a consistent manner. Hence, if something truly is possible,
then it exists in a possible world.
(3) is the premise that confuses the average layperson. Why should it be so
that if a maximally great being exists in one possible world, he exists in
all? Because such a being holds its greatness and excellence in a maximal
way, it would do so in every possible world (else there would be a greater
being displaying more excellence—namely, the one who existed in all
possible worlds).
The fourth premise is just true analytically. The actual world belongs to
the set of all possible worlds. This is because if the actual world were not
possible, it would not be actual! But then (5) follows, and the maximally
great being does in fact exist.
So it seems the crucial premise is the first one. Epistemically, one may say
it is possible God does exist and possible he does not. However, we are
interested in metaphysical possibility. It is on these grounds one must
object. That objection can come in two forms: A. The concept of a maximally
great being is incoherent,[2] or B. We do not (and/or cannot) know whether
or not the concept of a maximally great being is metaphysically possible.
With respect to (B), it’s not at all clear why we cannot justifiably intuit
such a being is metaphysically possible (even if it’s not
epistemologically compulsory that we do). With respect to (A), it seems the
maximum values of what we would call “great-making” properties are
coherent, and hence it follows they are metaphysically possible.[3]
John Feinberg, a Christian theologian, remarks on his interest in the
ontological argument but seems to show agreement with its critics. He wrote,
“what . . . [the ontological argument] proved is that a contingent being
could not be God. Any being worthy of the title ‘God’ must be a necessary
being.”[4] The philosophical rub Feinberg seemed not to catch, however, was
this: in modal logic, a being or truth that is necessarily true means it is
impossible not to exist. A necessary corollary or entailment of some being
or truth being necessary is that if it does turn out to be false, it is
necessarily so. So the MOA demonstrating the maximally great being’s
necessary existence does more than give us a curious fact. Rather, it
establishes that God’s existence is either necessary or impossible. Either
the maximally great being is possible or impossible. This is why it is such
a great argument! | E*****m
发帖数: 25615 | | j*******7
发帖数: 6300 | 3 您看出道理了吗？
【在 E*****m 的大作中提到】
: 你麼你懂了嗎？ 看出錯誤了嗎？
| E*****m
发帖数: 25615 | 4
早看出錯誤
【在 j*******7 的大作中提到】
: 您看出道理了吗？
| j*******7
发帖数: 6300 | 5 我也再跟您浪费一楼。这声势已经够了，能来点实在的吗？
【在 E*****m 的大作中提到】
:
: 早看出錯誤
| E*****m
发帖数: 25615 | 6
另外一貼說了
【在 j*******7 的大作中提到】
: 我也再跟您浪费一楼。这声势已经够了，能来点实在的吗？
|
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