Immanuel Kant
German philosopher Immanuel Kant (1724-1804) is a towering figure in modern philosopher and the last great thinker of the Enlightenment. His thoughts touch upon every aspect of philosophy, including ethics and the existence of God. Kant was greatly inspired by Hume's writings and developed many of his ideas. Kant launched a systematic attack on the traditional proofs for God's existence (he also named them!). He's most famous for his criticism of the Ontological Argument but he also launched some effective criticisms of the Cosmological Argument too.
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Kant's questions are so strange and arresting that no one who has once heard them ever forgets them - David Stove
Criticising the Cosmological Argument
God is not Uncaused
Kant makes a distinction between two types of reality:
Kant puts his criticism like this:
- Phenomen: the reality we experience through our senses
- Noumenon: reality as it actually is
Kant puts his criticism like this:
If the Supreme Being forms a link in the chain of empirical conditions, it must be a member of the empirical series, and like the lower members which it precedes, have its origin in some higher member of the series - Immanuel Kant
So if God is part of phenomenal reality, he must obey the rules of phenomenal reality and have a cause. If he isn't part of phenomenal reality, then maybe he really can be Uncaused... but we can have no knowledge of him.
God is not Necessary
Kant also argues that the Cosmological Argument depends on the Ontological Argument being true. He does this by distinguishing 3 types of Necessity:
Kant argues that God isn't Metaphysically Necessary because, if God doesn't have Logical Necessity, then he might not exist in any possible world.
God can't be Factually Necessary either, because, if he isn't Logically Necessary, then he might not exist, which would mean he could never come into existence later.
So the only important question is, is God Logically Necessary. This was a point answered earlier by David Hume: you can imagine a universe with no God in it. This suggests God is not Logically Necessary.
- Logical Necessity: something is logically necessary if it is contradictory to imagine its opposite. For example, a 3-sided triangle is logically necessary because it makes no sense to think of a triangle with 2 or 4 sides.
- Metaphysical (or Modal) Necessity: something is metaphysically necessary if it has to be true in any possible world. For example, you might have 11 people in your cricket team but you could have had 10 or 9 (in other possible worlds). But you couldn't have had 0 because then there'd be no team at all.
- Factual Necessity: something is factually necessary if it cannot start or stop existing. This means, if it exists it must always exist, forever. But if it doesn't exist then it can never exist.
Kant argues that God isn't Metaphysically Necessary because, if God doesn't have Logical Necessity, then he might not exist in any possible world.
God can't be Factually Necessary either, because, if he isn't Logically Necessary, then he might not exist, which would mean he could never come into existence later.
So the only important question is, is God Logically Necessary. This was a point answered earlier by David Hume: you can imagine a universe with no God in it. This suggests God is not Logically Necessary.
Kant concludes that the Cosmological Argument is irrelevant. Only the Ontological Argument can prove God is Logically Necessary and the Cosmological Argument needs God to be Logically Necessary before it can "get off the ground". However, Kant has some powerful criticisms of the Ontological Argument too.
Criticising the Ontological Argument
Kant's objection to the ontological argument is that you can't define something into existence. Kant shows this in a number of ways:
1. Negation is not contradiction
Kant argues that you don't contradict the definition of something by denying it exists. He uses Descartes' example of a triangle. Descartes had said that denying God's existence was like denying a triangle had three sides. Kant agrees that you cannot deny the predicate (no three-sidedness) and keep the subject (a triangle). However you can deny the predicate AND the subject both at once (no three-sidedness AND no triangle).
Kant argues that you don't contradict the definition of something by denying it exists. He uses Descartes' example of a triangle. Descartes had said that denying God's existence was like denying a triangle had three sides. Kant agrees that you cannot deny the predicate (no three-sidedness) and keep the subject (a triangle). However you can deny the predicate AND the subject both at once (no three-sidedness AND no triangle).
It would be self-contradictory to posit a triangle and yet reject its three angles, but there is no contradiction in rejecting the triangle TOGETHER WITH its three angles - Immanuel Kant
2. Existence is not a predicate
Kant denies that existence is a predicate in the way that "roundness" or "greenness" are predicates. He argues that, when you state that something exists, you are not adding another predicate to its definition. Instead, you are claiming that this definition can be checked in the real world. Bertrand Russell uses the term "instantiates" for this idea: saying that something exists is saying that its definition has been instantiated.
Kant shows this by inviting you to consider two piles of a hundred gold coins, one real (in re) and one imaginary (in intellectu). The two piles have exactly the same description: there are 100 coins in each pile, they're made of gold, they're round. Adding "... and it exists!" to the description of one pile doesn't change its description: it just means you can find it in the world.
Another way of thinking about this is to consider what it means to say God doesn't exist. Consider these two propositions:
Now consider these two propositions:
Kant shows this by inviting you to consider two piles of a hundred gold coins, one real (in re) and one imaginary (in intellectu). The two piles have exactly the same description: there are 100 coins in each pile, they're made of gold, they're round. Adding "... and it exists!" to the description of one pile doesn't change its description: it just means you can find it in the world.
Another way of thinking about this is to consider what it means to say God doesn't exist. Consider these two propositions:
- There is a God and he answers prayers
- There is a God and he doesn't answer prayers
Now consider these two propositions:
- There is a God and he exists.
- There is a God and he doesn't exist.