In Your Own Time

The Internet Encyclopedia of Philosophy:

“George Berkeley

“He was an idealist: everything that exists is either a mind or depends for its existence upon a mind. He was an immaterialist: matter does not exist. He accepted the seemingly outrageous position that ordinary physical objects are composed solely of ideas, which are inherently mental. He wrote on vision, mathematics, Newtonian mechanics, economics, and medicine as well as philosophy. In his own time, his most often-read works concerned the medicinal value of tar-water.”