George Berkeley - The Great Idealist (BBC In Our Time)

source: Philosophical Overdose    2015年11月22日
George Berkeley was an Anglican bishop who was one of the most important philosophers of the eighteenth century. He was an empiricist who believed that all ideas and knowledge must ultimately be based on our own sense experience, and that objects themselves are nothing but mere collections of qualities or ideas that exist in the mind, a view called immaterialism or idealism. His interests and writing ranged widely, from the science of optics to religion and the medicinal benefits of tar water. His work on the nature of perception and knowledge was a spur to many later thinkers, including David Hume and Immanuel Kant. The clarity of Berkeley's writing, and his ability to pose a profound problem in an easily understood form, has made him one of the most admired early modern thinkers.

Berkeley's subjective idealism seems crazy, but many took him to have a point. Insofar as we only have direct access to our own inner mental representations (e.g. perceptions, ideas, experiences), how could we possibly ever know, or even meaningfully speak or think about, an independent external world? As Berkeley pointed out, an idea can only resemble and represent another idea. So even if there was some underlying material substance behind the appearances, causing sensory impressions within us, we have no way of getting at such. For, we only ever encounter our own inner mental representations and can never step outside to compare such representations with some external mind-independent reality beyond.
Melvyn Bragg discusses the work of George Berkeley with Peter Millican, Tom Stoneham, and Michela Massimi. This is from the BBC radio program In Our Time.