一道存在了一千多年的逻辑难题，挑战各位的脑力

celesteazure

St. Anselm的上帝存在的本体论论证
为了让大家看得清楚些，我把它用逻辑的方法说一下。（原文都是混在一起的诗体……）
premise 1: 如果有上帝，上帝是"nothing greater than which can be conceived"
premise 2: 如果有个东西，than which nothing greater can be conceived，那么它肯定存在
conclusion: God exists.
   proof for premise 2:
如果有个东西A，than which nothing greater can be conceived，它不存在，那么我们可以想象这个东西是存在的，设为B。那么，我们可以想象一个东西B，than which nothing greater can be conceived，而且是存在的。那么B is greater than A，因为它有A的所有特征，而且是存在的。所以有矛盾，因为我们能想象一个B greater than A, but A is than which nothing greater can be conceived. Therefore, A exists.

我想各位大部分人和我一样是不相信上帝存在的。那么这个证明有什么问题吗？
一个objection是在这里，我们把存在也作为是great的一个标准，你可以argue它有问题。但这样的话，证明上帝存在就没有那么大意义了。我希望大家能讨论讨论这个问题。谢谢。

celesteazure

还有，第一个premise是没有问题的，因为它是一个上帝的定义。第二个premise是证明这个定义对应的东西是存在的。合起来就是上帝存在。那么哪里有问题？

StephanieYun

1.  如果不是你把premise 2的论证说的不清楚， 假设你已经把premise 2说得很清楚无误，那么premise 2错漏百出！建议你再看看premise 2， 或者， 你叙述的premise 2, 的论证。


2 . 由premise 2 推出 premise 1 是不必然。 注意命题形式. 结论应该是上帝存在的前提条件存在，但上帝不必然就会因此而存在。

欢迎讨论啊








生活是一杯清茶

celesteazure

嗬嗬，我知道它的问题在哪里啊。我写过paper的。当然我们认为的问题不一定一样。我也是注重在premise 2 上的。你认为它是什么毛病呢？
不过我认为，如果premise 1, 2都成立，那么结论的确是成立。而premise2并不是推出premise 1。两个premise相对独立。premise 2的目的是证明有一个东西，它是than which nothing greater can be conceived而且是存在的。premise 1只是把这个东西定义为上帝。

celesteazure

用google查了一下。

这是原文。注意，它包括了两个论证。我上面说的是第一个。第二个比第一个要有意思一些，但是是建立在第一个的结论上的。

CHAPTER II

That God Truly Exists

Therefore, Lord, you who give knowledge of the faith, give me as much knowledge as you know to be fitting for me, because you are as we believe and that which we believe. And indeed we believe you are something greater than which cannot be thought. Or is there no such kind of thing, for "the fool said in his heart, 'there is no God'" (Ps. 13:1, 52:1)? But certainly that same fool, having heard what I just said, "something greater than which cannot be thought," understands what he heard, and what he understands is in his thought, even if he does not think it exists. For it is one thing for something to exist in a person's thought and quite another for the person to think that thing exists. For when a painter thinks ahead to what he will paint, he has that picture in his thought, but he does not yet think it exists, because he has not done it yet. Once he has painted it he has it in his thought and thinks it exists because he has done it. Thus even the fool is compelled to grant that something greater than which cannot be thought exists in thought, because he understands what he hears, and whatever is understood exists in thought. And certainly that greater than which cannot be understood cannot exist only in thought, for if it exists only in thought it could also be thought of as existing in reality as well, which is greater. If, therefore, that than which greater cannot be thought exists in thought alone, then that than which greater cannot be thought turns out to be that than which something greater actually can be thought, but that is obviously impossible. Therefore something than which greater cannot be thought undoubtedly exists both in thought and in reality.



CHAPTER III

That God Cannot be Thought Not to Exist

In fact, it so undoubtedly exists that it cannot be thought of as not existing. For one can think there exists something that cannot be thought of as not existing, and that would be greater than something which can be thought of as not existing. For if that greater than which cannot be thought can be thought of as not existing, then that greater than which cannot be thought is not that greater than which cannot be thought, which does not make sense. Thus that than which nothing can be thought so undoubtedly exists that it cannot even be thought of as not existing.


And you, Lord God, are this being. You exist so undoubtedly, my Lord God, that you cannot even be thought of as not existing. And deservedly, for if some mind could think of something greater than you, that creature would rise above the creator and could pass judgment on the creator, which is absurd. And indeed whatever exists except you alone can be thought of as not existing. You alone of all things most truly exists and thus enjoy existence to the fullest degree of all things, because nothing else exists so undoubtedly, and thus everything else enjoys being in a lesser degree. Why therefore did the fool say in his heart "there is no God," since it is so evident to any rational mind that you above all things exist? Why indeed, except precisely because he is stupid and foolish?


这是分析。

Saint Anslem's argument for the existence of God


Anselm, a famous medieval religious philosopher has, like many before, and after him, tried to come up with a proof that God does in fact exist. His proof is a controversial one because it requires that you have somewhat of a religious background to accept it. It was, however, widely accepted and used by other religious philosophers during his time, and after it to either support, accent, or strengthen their own arguments.


Anselm was a man if strong faith, and yet, he adored reason. His argument plays on a catch twenty two of our reason, he almost uses our reason to defeat it. It is very interesting how he sets his argument up, and it is well respected for the "trap" that he was able to set up.


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To begin his argument, Anselm must first establish that God is the equivalent to "something that which nothing greater can be thought." Since the idea of God is an idea of perfection, the common explanation for God at the time of Anselm was just that. Since perfection can not be improved upon, then nothing greater can be imagined. From here, he takes a look at the passage in the bible that says, "the Fool has said in his heart, there is no God." He begins to contemplate if and why this statement is true. He decides that it is true, and he comes to the conclusion that they must be a fool because that very statement contradicts itself. He argues that in saying the word "God" you are acknowledging that you have an idea in your mind of something than which nothing greater can be thought.



From here he states that because we are able to conceive of such a perfect being, then one must exist. If one did not exist then that would mean that it wasn’t perfect, and therefore there is something out there that is greater. The idea of a being that nothing greater can be thought of had to be put there by something, and that something is the real being, which is God. He argues that we couldn’t have just come up with it since we as humans are flawed and are incapable of perceiving perfection unless it has been shown to us by something that is perfect.


For example, we can’t know what a circle looks like without the idea of a perfect circle. This is the area with which most people argue. The most common argument is that anyone can imagine anything, and that does not mean that it does in fact exist. For example a person can imagine a purple polka dotted five eyed monster, but no matter how often people think of it, it will not come into existence.


His proof has been accepted, and has been denied. It has been called one of the greatest, and one of the worst proofs for the existence of God. None the less, it has made an impact on philosophy from the day it was published, all the way up to present time.

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God is: "that than which nothing greater can be conceived" Reformulated to: "the thought object than which no thought object can be thought to be greater".

(1) God is the thought object than which no thought object can be thought to be greater

Now suppose that

(2) God is only in the intellect (i.e. God is thought of, but does not exist)

But certainly

(3) any thought object that can be thought to exist in reality can be thought to be greater than any thought object that is only in the intellect

And it cannot be doubted that

(4) God can be thought to exist in reality

Therefore,

(5) Some thought object can be thought to be greater than the thought object than which no thought object can be thought to be greater which is a contradiction, whence we have to abandon our supposition that God is only in the intellect, so he has to exist in reality, too. Implied from [1,2,3,4]