How is Kant's transcendental idealism related to Berkeley's subjective idealism?

Question

My understanding is that Berkeley considered the outside world to have no existence at all, and took the statement "It's all in the mind" literally, whereas Kant argued that the outside world exists independently of the observer, but we can never know it's true nature. The best we can due is observe the effects it has on our senses. I'm pretty sure this description of the difference is correct, but it feels oversimplified to me (My grasp of Kant is rudimentary at best).

• Is this a good way of describing the difference? Or is a more nuanced (yet still non-technical) explanation of the difference possible?

Answer 1

There is a very good and well-sourced article on Kant's refutation of Idealism on SEP.

As the answer in this question tried to say, it is essentially about an objective foundation of time.

From the SEP article linked:

George Dicker provides a compelling initial representation of Kant's argument (Dicker 2004, 2008):

1. I am conscious of my own existence in time; that is, I am aware, and can be aware, that I have experiences that occur in a specific temporal order. (premise)
2. I can be aware of having experiences that occur in a specific temporal order only if I perceive something permanent by reference to which I can determine their temporal order. (premise)
3. No conscious state of my own can serve as the permanent entity by reference to which I can determine the temporal order of my experiences. (premise)
4. Time itself cannot serve as this permanent entity by reference to which I can determine the temporal order of my experiences. (premise)
5. If (2), (3), and (4), are true, then I can be aware of having experiences that occur in a specific temporal order only if I perceive persisting objects in space outside me by reference to which I can determine the temporal order of my experiences. (premise)
6. Therefore, I perceive persisting objects in space outside me by reference to which I can determine the temporal order of my experiences. (1–5)

So the main difference is that while Berkeley would have to say that everything is subjective, because the mind is the only (ontological) reality that cannot be questioned, Kant's transcendental (!) idealism is an idealism that can infer, by transcendental philosophy, to an objective being, and is therefore always founded on experience of something (ontological) real that is different from the (phenomenal) self (under the name of nature). Only in the unity of the noumenal self you could say that all is one, but there are many discussions going on about that.
That is why the transcendental ideas are problematic concepts because they have no object in the experience of nature (A254|B310). Kant also says something about this in his Prolegomena (Prol.,4:373f., fn.).

Answer 2

Kant criticizes Berkeley in B274 of Critique of Pure Reason concerning the concept of space:

The second is the dogmatical idealism of Berkeley, who maintains that space, together with all the objects of which it is the inseparable condition, is a thing which is in itself impossible, and that consequently the objects in space are mere products of the imagination. The dogmatical theory of idealism is unavoidable, if we regard space as a property of things in themselves; for in that case it is, with all to which it serves as condition, a nonentity. But the foundation for this kind of idealism we have already destroyed in the transcendental aesthetic.

Answer 3

Swami Vivekananda said in the 1890s that Kant showed traces of the teachings of the Upanishads. Perhaps this quote from Vivekananda (Complete Works, V3, p 403-404 and available here under heading Lectures from Colombo to Almora, lecture titled "The Vedanta" http://cwsv.belurmath.org/volume_3/vol_3_frame.htm):

Along with it, you ought to understand one thing more that will help us in understanding the Advaita system later on. It is this. All of you must have seen pearls and most of you know how pearls are formed. A grain of sand enters into the shell of a pearl oyster, and sets up an irritation there, and the oyster's body reacts towards the irritation and covers the little particle with its own juice. That crystallises and forms the pearl. So the whole universe is like that, it is the pearl which is being formed by us. What we get from the external world is simply the blow. Even to be conscious of that blow we have to react, and as soon as we react, we really project a portion of our own mind towards the blow, and when we come to know of it, it is really our own mind as it has been shaped by the blow. Therefore it is clear even to those who want to believe in a hard and fast realism of an external world, which they cannot but admit in these days of physiology — that supposing we represent the external world by "x", what we really know is "x" plus mind, and this mind-element is so great that it has covered the whole of that "x" which has remained unknown and unknowable throughout; and, therefore, if there is an external world, it is always unknown and unknowable. What we know of it is as it is moulded, formed, fashioned by our own mind. So with the internal world. The same applies to our own soul, the Atman. In order to know the Atman we shall have to know It through the mind; and, therefore, what little eve know of this Atman is simply the Atman plus the mind. That is to say, the Atman covered over, fashioned and moulded by the mind, and nothing more.