had written nonsense so charmingly. Everyone discussed Berkeley's log ical attempt to annihilate matter among others, the lexicographer Samuel Johnson rejected the system, as Boswell reports After we came out of church, we stood talking for some time together of Bishop Berkeley's ingenious sophistry to prove the non-existence of matter, and that everything in the universe is merely ideal. I observed that though we are satisfied his doctrine is not true, it is impossible to refute it. I shall never forget the alacrity with which Johnson answered, striking his foot with a mighty force against a large stone till he rebounded from it. "i refute it thus But what had Johnson really proved by kicking the rock? He had merely illustrated and confirmed Berkeley s argument. For al Johnson"knew"was the sharp pain in his toe, perhaps a numb feeling in his foot, and the sensation of a sudden stop which gave his leg a jar. All he had proven by kicking the rock was that he was capable of feel ing a variety of subjective sensations. all he knew was his own experience, and that, after all, was the point Berkeley was making. So Samuel Johnson had merely added his considerable support to the philosophy of immaterialism 8 What else is this. however. but "charming nonsense"? Most of us are convinced(we think ) that physical matter exists. It seems to us that Berkeley made a simple mistake, a non sequitur: just because we cannot experience physical matter directly, it does not necessarily follow that matter doesn,'t exist But did Berkeley really go wrong? (1) Berkeley emphasizes the fact that we are limited a4solutely to our own perceptions and cannot cannot experience any real"world. On this point he seems to be correct. (2)He is therefore repeating Locke's point that physical matter (or substance) is only a mental assumption which we think to be a logical necessity on this point also, he is correct Whether you will go further with Berkeley and accept that his alternat ive ssumption--God as the source of experience-is a better one will depend somewhat on personal preference and theological belief. Most of us remain convinced that the reality of matter is a better assumption, but perhaps that's only b ecause we have llve uncritically with it most of our lives. We must face honestly, however, Berkeley's singular challenge: Prove, if you can, that any material object exists apart from your perception of it. If you can, then Berkeley is wrong. If you can 't, then you will have to concede berkeley would insist)that the world is merely your idea 9 If you enjoy science fiction, speculate on the following scene(which ay not be from the realm of SF We are alone, each of us, in a small white cubicle, floating restfully in curvolounges fashioned to fit from heliostyrene. Over each of our heads is fitted tantalum--crystal he l met, finely wired with thousands of microelectrodes which have been surgically embedded in the sensory centers of our brains outer layer, the cortex All senseq ("sensory--sequence")programs originate from, and are coordinated by, PROSELEC (Program Central for Sensory-sequence Selection). The electrical impulses which the electrodes generate in the cortex prov ide a variety of real --l ife experiences. Selection keys on the curvolounge's arm allow one to select fromhad written nonsense so charmingly." 7 Everyone discussed Berkeley's logica1 attempt to annihilate matter among others, the 1exicographer Samuel Johnson rejected the system, as Boswell reports: “ After we came out of church, we stood talking for some time together of Bishop Berke1ey's ingenious sophistry to prove the non-existence of matter, and that everything in the universe is merely ideal. I observed that though we are satisfied his doctrine is not true, it is impossible to refute it. I shall never forget the alacrity with which Johnson answered, striking his foot with a mighty force against a large stone, till he rebounded from it, "I refute it thus!" But what had Johnson really proved by kicking the rock? He had merely illustrated and confirmed Berkeley's argument. For a1lJohnson "knew" was the sharp pain in his toe, perhaps a numb feeling in his foot, and the sensation of a sudden stop which gave his leg a jar. All he had proven by kicking the rock was that he was capable of fee1ing a variety of subjective sensations. All he knew was his own experience, and that, after all, was the point Berkeley was making. So Samuel Johnson had merely added his considerable support to the " philosophy of immaterialism." 8 What e1se is this, however, but "charming nonsense"? Most of us are convinced (we think) that physical matter exists. It seems to us that Berkeley made a simple mistake, a non sequitur: just because we cannot experience physical matter directly, it does not necessarily follow that matter doesn't exist. But did Berkeley really go wrong? (1 ) Berkeley emphasizes the fact that we are 1imited a4soIutely to our own perceptions and cannot cannot experience any "real" world. On this point he seems to be correct. (2)He is therefore repeating Locke's point that physical matter (or substance) is only a mental assumption which we think to be a 1ogical necessity. On this point also, he is correct. Whether you will go further with Berkeley and accept that his alternative assumption--God as the source of experience--is a better one will depend somewhat on personal preference and theological belief. Most of us remain convinced that the reality of matter is a better assumption, but perhaps that's only because we have lived uncritica1ly with it most of our lives. We must face honestly, however, Berkeley's singular challenge: Prove, if you can, that any material object exists apart from your perception of it. If you can, then Berkeley is wrong. If you can't, then you will have to concede (Berkeley would insist) that the wor1d is mere1y your idea. 9 If you enjoy science fiction, speculate on the following scene (which may or may not be from the realm of SF). We are alone, each of us, in a sma1l white cubic1e, floating restfully in curvolounges fashioned to fit from heliostyrene. Over each of our heads is fitted a tantalum--crystal he1met, finely wired with thousands of microelectrodes which have been surgically embedded in the sensory centers of our brain's outer 1ayer, the cortex All senseq ("sensory--sequence") programs originate from, and are coordinated by, PROSELEC (Program Centra1 for Sensory-sequence Selection). The electrical impulses which the electrodes generate in the cortex provide a variety of real--1ife experiences. Selection keys on the curvolounge's arm allow one to select from