George Berkeley (whose name is pronounced "BARK-lee") was an Irish Anglican priest who later became a bishop.
The city of Berkeley
Is named after Berkeley!
In his early philosophical writings Berkeley made the claim that "esse est percipi", or that "to be is to be perceived". In other words, according to him, what we take to be the material world and its contents are in reality only "ideas" which are perceived by our minds. But it is no good trying to add to your wealth by forming a new idea that there are a lot of gold coins in your purse; supposedly only God has a mind powerful enough to do things like that!
Berkeley is the most notorious prophet of philosophical IDEALISM, the doctrine that all religious people uphold to one degree or another, that ideas and the mind exist independently of matter. Soft-core idealists believe that matter also exists independently of mind (see DUALISM), but Berkeley's hard-core brand of idealism—known as "subjective idealism"—essentially explains away matter as a subjective "illusion" of mind.
And God-appointed Berkeley that proved all things a dream,
That this pragmatical, preposterous pig of a world, its
farrow that so solid seem,
Must vanish on the instant if the mind but change its theme.
—William Butler Yeats, "Blood and the Moon"
The following two limericks make fun of Berkeley's screwy theory that "to be is to be perceived".
The philosopher Berkeley once said
In the dark to a maid in his bed:
"No perception, my dear,
Means I'm not really here,
But only a thought in your head."
—P. W. R. Foot
A philosophical hippie
Contended "Esse est percipi"
He became much aggrieved
When no longer perceived,
"I'm a gonner!" said he, "Whoa, how trippy!"
By the way, Jeff Defty, in college in Oregon, and who sent me that last item, describes himself as a "recovering philosophy major"!
In later life Berkeley focused more on an unsuccessful attempt to found a college in Bermuda for "the propagation of the gospel among the American savages", and on promoting what he claimed to be the "universal curative properties" of tarwater. It is truly amazing that this guy is still taken seriously even in bourgeois philosophy!