ABSTRACT
If you ask brain scientists 'What are perceptions made of?' they will scratch their heads. If you ask physicists 'What is matter made of?' they will scratch their heads and say it is a silly question. Yet such questions are mental (and dinner money) meals for philosophers. Following years of thought a philosopher may decree that they are meaningless - not on the menu - but this will be claimed, perhaps rightly, as discovery, for an important way of answering a question is to show that it has no meaning. The Verification Principle of the Logical Positivists (Ayer 1936) claimed that questions lacking any conceivable test, by observation or experiment, of suggested answers are strictly meaningless. Thus not very long ago it was claimed that to ask whether there are mountains on the back of the moon is meaningless - until a Russian rocket photographed it, finding mountains! Technology keeps pushing back the frontiers of what cannot be asked as new techniques extend observations and experiments for testing suggested answers.
