Not a substratum. Material is all there is--well, material, relations of material and motion of material. We're not positing things we don't observe. — Terrapin Station

No one has ever sensed matter. We do not observe matter. The things we observe are objects like the chair, the table, and the various other objects we encounter. To say that these things are somehow composed of matter is to posit something we do not observe, matter, as a material substratum.

We do not observe matter. — Metaphysician Undercover

Who says something like that?

If you really think that you've observed matter before, tell me what does matter look, sound, taste, smell, or feel like?

Matter occupies space and - in common day life - has a weight. Anything that has these properties is made of matter. That's the definition.

Actually not naive realism, but Berkeley is categorised as an empiricist. His argument could be paraphrased as depending on the observation that we cannot go beyond the content of experience, and that experience requires a perceiving subject. — Wayfarer

He is an empiricist, no doubt. Why do you say he theory is not direct realism? By refuting abstract ideas and the primary / secondary quality distinction the veil of perception disappears. We are left with direct access to the object itself (even if it is only an idea in our head) hence I called it naive / direct realism.

Matter occupies space and - in common day life - has a weight. Anything that has these properties is made of matter. That's the definition. — Heiko

You oversimplify it with your partial definition.

mat·ter
/ˈmadər
noun
1.
physical substance in general, as distinct from mind and spirit; (in physics) that which occupies space and possesses rest mass, especially as distinct from energy.
"the structure and properties of matter"

Newton asserts the absolute existence of matter, force, time and space. Berkeley undermines their absolute / independent existence by offering an alternative cause in God.

No one has ever sensed matter. We do not observe matter. The things we observe are objects like the chair, the table, and the various other objects we encounter. To say that these things are somehow composed of matter is to posit something we do not observe, matter, as a material substratum. — Metaphysician Undercover

When we see a chair, how do we not see what it is composed of? If we can't say what it is composed of, how can we even say that what we see is a chair?

The question is: does it even matter what word we use to say what the chair is composed of?

Berkeley devotes volumes to demonstrating that the notion of an existent or mind-independent object can’t be demonstrated. That’s his whole shtick. What is real, for Berkeley, is mind, or actually spirits.

Objects are real for Berkeley too, they just are not material.

Which undercuts materialism - the main purpose of his philosophical project.

but surely direct realism the perception of the object as it is. We cannot see matter only material objects, according to Locke and so their true nature is beyond our experience and our understanding. We cannot have true knowledge of the object.

With Berkeley the object is as we perceive it, no annoying atoms or bothering quarks or other particles, just the pure idea in itself. Berkeley was a great scholar of Plato and I am sure that the theory of Forms is being exploited here by him.

Why is that oversimplified? The basic definition of material objects was given.
Mass is a good keyword. Mass implies inertia. Reality is resistance.

How do you experience mass? Can you see it directly?

Weight. Resistance.
Per definition: a measure of matter.

Ok but how can you prove that these things exist independently of our perceptions of them?

No the point about Locke was 'representative realism' - that the idea represents the supposedly real material particular that is sensed. Remember it was Locke that said the mind is tabula rasa, a blank slate, on which experience engraves ideas. But he still gave primacy to the object itself. The mind was the domain of the 'secondary qualities' - yolk that to Galileo's concept of mass (etc) as ‘primary’ and you have the foundation of modern scientific empiricism, which invariably gives primacy to the 'reality of the experienced object'. Indeed everything is supposed to point back to that, or reveal it. But now look at the massive conundrums that have enveloped physics itself! The supposedly self-evident reality of objects has dissolved into a sea of arcane mathematical and philosophical problems.

Speculation is not my primary buisiness.

One of us seems to be a bit mixed up here. https://en.wikipedia.org/wiki/Direct_and_indirect_realism

Speculation is not my primary buisiness. — Heiko

Every time you take for granted that objects exist independent of perception you are actually speculating.

No you are not an idea, you are a mind / spirit. — Jamesk

Spirits dull or impair the mind. :)

Anyway, Berkeley conjured up his deity as a coat hanger for his world, a mental monism, like others have come up with whatever other things.
But it's the justification that matters.

I guess it's impossible to get things wrong, there's nothing more to things than the experience, there's no difference between hallucination and perception, for example?



We don't perceive and learn when unconscious.
We don't experience another's self-awareness.

There are few odd things by subjective idealism on its own, a kind of solipsism.

Of course. But that does not say anything about the definition of the thing, does it?

A professor once told me that we can't do philosophy only by definitions.

Because you are trying to give some? I did so.

I need to reread my Berkeley but he definitely does make allowances for the dreaming / hallucination argument he also covers himself against solipsism. I will go through it again and try to find the relevant examples.

One of us seems to be a bit mixed up here. — Jamesk

Right. So according to the article that you cited:

The question of direct or naïve realism, as opposed to indirect or representational realism, arises in the philosophy of perception and of mind out of the debate over the nature of conscious experience;[1][2] the epistemological question of whether the world we see around us is the real world itself or merely an internal perceptual copy of that world generated by neural processes in our brain. Naïve realism is known as direct realism when developed to counter indirect or representative realism, also known as epistemological dualism,[3] the philosophical position that our conscious experience is not of the real world itself but of an internal representation, a miniature virtual-reality replica of the world.

According to the same source (i.e. Wikipedia):

George Berkeley- known as Bishop Berkeley (Bishop of Cloyne) – was an Irish philosopher whose primary achievement was the advancement of a theory he called "immaterialism" (later referred to as "subjective idealism" by others). This theory denies the existence of material substance and instead contends that familiar objects like tables and chairs are only ideas in the minds of perceivers and, as a result, cannot exist without being perceived.

So I don't see how Berkeley fits into (1).

You appear to be right on this, I was oversimplifying it. Berkeley is into Contra direct realist materialism. https://plato.stanford.edu/entries/berkeley/

I have a huge problem writing about idealism. I swear before each exam never to answer questions on Idealism but the subject fascinates me so much and I spend too much of my time studying it out of pure interest.

No problems, it’s been a great discussion of a tricky topic.

I think that any school of idealism requires a kind of gestalt shift. Realists struggle with it, because of their habitual stance of being ‘a subject in a realm of objects’, which is simply assumed as the basis of all enquiry. Whereas idealism of all kinds focusses on the act of knowing and the role of the subject, which is generally ‘bracketed out’ by realists. I sometimes think of it in terms of Lewis Carrolls’ Through the Looking Glass - I’m sure he was wise to these ideas.

Yes indeed. Newton asserted the absolute independent existence of matter, force, space and time upon which our science is based. Berkeley shows that we cannot know material without a material object, force without something being forced, space without something occupying it and time without some agent passing through it.

Berkeley shows that we cannot know material without a material object, force without something being forced, space without something occupying it and time without some agent passing through it. — Jamesk

In short, I can't perceive anything if I'm not around.
But that does not entail that anything isn't around.
Conflating epistemics and ontology (which, I think, has been pointed out plenty over time).
Similarly ...

We don't experience another's self-awareness — jorndoe

... even when around, hence ...

Berkeley shows that we cannot know — Jamesk

... another's self-awareness, which would then prompt Berkeley to deny existence (except by special pleading).
Solipsism by Berkeley's own line of thinking.
In fact, as indicated by the image above, knowing someone else's self-awareness is even harder than knowing the existence of their (object-like) hands, for example.
We encounter other people's "physical" bodies before their minds, we encounter their minds via their bodily goings-and-doings.

Again this is not an attempt to defend Berkeley, I want to compare his theory with Locke's. You are perfectly correct in questioning whether first person introspection is the proper place to begin our scientific inquiries, however that is exactly what Locke does for his materialist thesis.

Berkeley and Locke take this from Descartes. Berkeley recognizes the weakness in his argument and defends against the objections. Introspection provides us with notions of ourselves and things like us, spirits in other words. Again it gets very Cartesian at this point and cannot work without God.

Here the question is whether he is a scientist, a christian, a scientific christian, is he trying to prove science or God or one through the other.