8 Video Lectures on Kant's Critique of Pure Reason by Professor Dan Robinson. From Youtube Channel Philosophy Overdose.
This is an informative and entertaining playlist of videos that introduce the main concepts of Kant's Critique of Pure Reason.
I like to take notes as I listen to lectures in order to help me learn/remember the ideas and terms. Maybe they will be helpful to someone out there:
Kant says: Time is not in the sensation. Space is not in the sensation. Kant says space and time are a priori, or that they are the "forms" of consciousness that the sensations filter through to create ideas/concepts.
The manner in which the external world is objectified is according to rules. Universal and necessary within a community of human beings. The rules that govern the synthesis of the manifold of sensuous content, are universal and necessary. It is possible that some other creature could subsume sensuous content under different rules. Experience and these rules make up all knowledge. Without either, nothing can be known. (Kant agrees with Hume that without experience there is no knowledge, but he says hume made the mistake of leaving out the necessary elements of cognition for there to be experience in the first place) There are necessary conditions of consciousness in order for there to be experience.
What assumptions does Kant's metaphysical system rely on?
This thing is black and wet and hot and round. Without the synthesis of experience (pure categories of the understanding) you can never get a cup of coffee out of this.
How does a dog see a tree? They would experience a tree but they would not conceptualize it the same as we do.
St Augustine said: everyone can perceive a square, so everyone can conceive of a square. But everyone can conceive of a chiliagon (1000 sided figure) but they cannot perceive it. The minute change in angles between legs is too small to see. (I'm not sure I buy this)
Kant was attempting among other things to prove the existence of an external world and to prove that it is knowable by humans.
Kant thought he could prove basic synthetic a priori propositions such as "every event has a cause" and "substance is neither created nor destroyed" if we go through this copernican revolution and make the world to some extent dependent on our minds rather than hoping that our mind will fit a world that exists entirely independently from it.
Idealism = something about the world is dependent on the mind. (Maybe you think colors are just in our mind, that the world as it is itself isn't really colored. You would be an idealist about color) Kant was an idealist for the concepts of space and time. Space and time are only in our minds. They do not exist outside of our minds. But he does believe there is a world "out there."
Kant's theory makes allies of mathematics and a noumenal world. He believes in math and so he accepts that there is a noumenal world.
We can only know things with universality and necessity. Synthetic a priori propositions are universal and necessary. You can't prove 7 + 5 = 12 or "every event has a cause" with experience or with analysis of the meaning of the terms involved. You can only prove them if space and time belong to the mind.
Hume started by casting doubt about whether we can know anything at all. Kant started with the assumption that we can know some things. He thinks we can know mathematics and things like that and goes on to ask what is required of our minds in order to know these things.
He thinks we cannot know whether we have free will or not. (We cannot know this by means of theoretical reason) We can't prove that we do or that we don't. Or that the soul is immortal... etc.
Why does Kant think that there is a noumenal world? It's because his copernican revolution clarifies disputes and contradictions that the original model has. The contradictions disappear if you accept his copernican revolution.
Deductive reasoning is: all men are mortal + Socrates is a man >therefore> Socrates is mortal.
Inductive reasoning is: (basically all probability) there are 20 black and white balls in a bucket. You take a sample of 4 balls and only get 1 black ball. By induction you propose that there are 5 black balls and 15 white balls in the bucket.
Sebastian Gardner writes a guidebook on Kant's Critique of Pure Reason.
Kant's noumena: there are aspects of reality that are inferrable but not knowable.
For Kant: Facts of the world are contained in synthetic propositions. Synthetic proposition: "This contains both metal and glass." "This is capable of holding a fluid." "This is blue." They pull together sensory data to identify something. They can ONLY be established by experience (a posteriori).
Hume says the truth of NO synthetic claim can be established a priori. Reason cannot unearth the facts of the world on its own resources. If you want to establish the truth of any synthetic claim it will be based on experience and therefore be subject to skepticism. Errors in senses...specific to certain species...dependent on age of the observer… etc… so Kant says it comes to the failure of metaphysics: the inability to prove the existence of an external world. So Kant is going to try to prove that we actually can prove the truth of at least one synthetic argument.
Kant says math and physical sciences are already riddled with synthetic a priori propositions that are known to be true. "There's no number so large that 1 cannot be added to it." That's true. A radical empiricist would run out of fingers and toes trying to prove it by counting. "Every effect has a cause." "There is no line so long you can't increase its length."