Berkeley downplays matter in order to focus on the senses. Perception (senses) determines reality. For Berkeley, there is no such thing as matter without a mind, because it always a mind that perceives matter. So even if a {human} mind is not perceiving a chair in an empty room, it still exists because God is always perceiving it.

Basically, because Berkeley thinks mind-independency is incoherent and inconcievable without a mind, so-called mind-independent things (like matter) really are mind-dependent because we're thinking about it right now!

Yeah. To be is to be perceived. But then, which comes first? The thought of the perceive or the perception of matter? How does sensation come about? Is it by the mind placing objects externally?

Berkeley wrote that "Everything we see, hear, feel, or any way perceive by sense, being a sign or effect of the power of God; as is our perception of those very motions."

So the thought or Ideas of the perceiver organizes the perception of matter. God organizes matter in a certain way, to create human minds, and these minds organizes objects either through the senses, imagination or memory, grouped in certain ways by our mind; round things are round, a certain colour is blue, etc. And for Berkeley, God enables these things.

Esse est Percipi! Berkeley... the odd man out.

Berkeley seems to me one of the odd-men out in the empiricists. I have never been a huge fan of Berkeley though? not so riveting as Locke or Hume. But I was really fascinated with principles of Human Knowledge and his thesis on immaterialism though. If I could surmise Berkeley from that treatise that (considering the empiricist conception that knowledge come from our experience), we are aware of nothing but our ideas, we have no reason to suppose in the existence of matter? or indeed any conception of it. This is a huge and abstract wall between Locke and Hume, especially considering Locke's stance on innate ideas. To be honest, there is a valid question why Berkeley, a man who essentially says "there is no material substance" sits in between Locke and Hume. I think empiricists, especially modern ones that are so consumed by the scientific aspects of what-it-is-to-be empirical are not too keen to accept Berkeley's notion that the only thing that exists are "spirits." The main word that always stuck to me when I was learning about Berkeley was not empiricist or immaterialist, but actually "corpuscularian."

In answer to one of your questions "how come Berkeley downplayed the value of matter?", I would suggest Principles of Human Reasoning, but specifically 7 and 9. It's interesting, but the argument really isn't that long, it's just really obscured. I narrow it down like this;

1.If material substances are those in which sensible qualities are predicated of, then those qualities are the said features of material substances.

2.Also, sensible qualities are perceived through the senses, so they are then ideas.

3.So? material substance is that which ideas are predicated of.

4.But having those ideas is to perceive

5.So considering that, the notion of material substance as being unthinking substances is not right because for an idea to exist in an unperceiving thing is a huge contradiction.

Give me a month or two and I will be up for discussing Berkeley considering my Early Modern Philo class calls for me to read his dialogues.

Thanks VideCorSpoon. Theaetetus I'll wait for your response.

Because he thought that the senses really do not give us any reason to suppose that there is matter, and, in fact, quite the opposite.

An interesting read;

On Berkeley and Advaita

But even if it is, it has nothing whatever to do with the question.

Thankyou for your opinion on the OPs intent and meaning.
I think that the mention of;

indicated that the more of 'Berkeley' that was known and understood, of his thoughts, from as many Perspectives as possible, that it would help satisfy the implied question in the above quote; perhaps provide 'improved understanding'.
Capisce'?
nameless out

Not everything about Berkeley concerns why, if B. is an empiricist, how he can also be an Idealist. For instance, knowing that B. once went to California would help with the question. From what I can see, the book you recommended would not help with any question about B. But that is something different.

Berkeley says that we never experience matter, we only experience mind. That is, when you see a chair, you are experiencing your mind, not the chair. We can not infer that the chair exists outside a mind, because we never experience the chair... We only experience the mind...

God, being the wonderful guy that he is, would not create such a confusing dualism for people to live in... In other words, god would not confuse us by creating a mental, detached from the physical. Therefore, god would only create the mental, and we would be directly aware of its existence. So, everything in the world is a representation of gods mind. And since we experience things as mind, we experience the world directly, because the world is mind.

Furthermore, he is an empiricist because he believes that all knowledge comes from experience.