The third argument for God, a philosophical argument, is the Ontological Argument first written up by Saint Anselm in the 11th Century. It follows 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 exists in some possible world.
3. If a maximally great exists in some possible world, then it exists in every possible world.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. If a maximally great exists in the actual world, then a maximally great being exists.
6. Therefore, a maximally great being exists.
This argument is very simple and true. If an MGB(Maximally Great Being) could exist, then an MGB would have to exist because it is maximally great. The MGB here is God. Let’s go through this argument with each premise.
First, it is certainly possible that an MGB could exist. An MGB would have to be all-knowing, all-powerful and morally perfect. However, only a maximally great being could exist instead of a maximally great pizza for example because it is an object and objects have no intrinsic value to rank it whether it is great or not. With a being who has a soul and a state of mind, we can conclude that it is maximally great. It is the greatest being ever. Next, if it is possible that an MGB exists then it has to be in a possible world. A possible world meaning any other world that includes different things that is logically coherent. A unicorn or a leprechaun exists in a possible world because it could exist. However, a Married Bachelor or a circle does not have pi as the ratio of a circle's circumference to its diameter.
We know an MGB could exist and is logically coherent, then it has to exist in every possible world. To illustrate this,let’s say we have 100 possible worlds. It is better to be in 56 of those 100 possible worlds than 14. It is better to be in more possible worlds than not. So, a maximally great being would have to maximally great in the fact that it exists in every possible world. Now, if God existed in every possible world, it would logically follow that God, an MGB, would exist in the actual world. Finally, if God existed in the actual world, it would exist now. God exists.
God is then defined as a necessary being then. In Philosophy, there are 3 different types of beings:
1.Contingent being: A being that could exist, but may not necessarily exist (such as a unicorn)
2. Impossible being: A being that is impossible, such as an invisible pink unicorn or a married bachelor.
3. Necessary being: A being who exists necessarily and whose non-existence is impossible (such as numbers, logic, etc).
God is a Necessary being because, in order to be maximally great, it has to be necessary. It is not an MGB if it is impossible to be formed or a Contingent being that could exist. Follow logically, and if an MGB could exist, which is most certainly can, then it has to exist.
This argument only applies to God. If you were to say that a maximally great pen could exist then it has to exist, couldn’t you say that anything in your imagination could exist? No, there are no definitions that could define a maximally great pen or cheeseburger, but there are real parameters for a MGB. However, even a pen could not be maximally great in the first place even if it was defined. You could always find a better pen and if you try to Think of the best possible pen, you can always think of one which is better. Until, eventually, you arrive at an all-powerful, all-knowing, all good, sentient pen which can change its form if desired and only appear to those it seems fit, etc, etc etc. in other words, you get God, choosing to take the form of a pen. Yet, if the pen was all-powerful and all-knowing and all good, and capable of taking any form, the question remains why it should stay a pen. God exists because of this classic 942-year-old argument.{LINK}
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 exists in some possible world.
3. If a maximally great exists in some possible world, then it exists in every possible world.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. If a maximally great exists in the actual world, then a maximally great being exists.
6. Therefore, a maximally great being exists.
We know an MGB could exist and is logically coherent, then it has to exist in every possible world. To illustrate this,let’s say we have 100 possible worlds. It is better to be in 56 of those 100 possible worlds than 14. It is better to be in more possible worlds than not. So, a maximally great being would have to maximally great in the fact that it exists in every possible world. Now, if God existed in every possible world, it would logically follow that God, an MGB, would exist in the actual world. Finally, if God existed in the actual world, it would exist now. God exists.
This argument only applies to God. If you were to say that a maximally great pen could exist then it has to exist, couldn’t you say that anything in your imagination could exist? No, there are no definitions that could define a maximally great pen or cheeseburger, but there are real parameters for a MGB. However, even a pen could not be maximally great in the first place even if it was defined. You could always find a better pen and if you try to Think of the best possible pen, you can always think of one which is better. Until, eventually, you arrive at an all-powerful, all-knowing, all good, sentient pen which can change its form if desired and only appear to those it seems fit, etc, etc etc. in other words, you get God, choosing to take the form of a pen. Yet, if the pen was all-powerful and all-knowing and all good, and capable of taking any form, the question remains why it should stay a pen. God exists because of this classic 942-year-old argument.{LINK}
