‘But the world itself is only a speck of dust. And man is tiny helpless! How long has he been in existence? For millions of years the earth was uninhabited.’
‘Nonsense. The earth is as old as we are, no older. How could it be older? Nothing exists except through human consciousness.’
‘But the rocks are full of the bones of extinct animals — mammoths and mastodons and enormous reptiles which lived here long before man was ever heard of.’
‘Have you ever seen those bones, Winston? Of course not. Nineteenth-century biologists invented them. Before man there was nothing. After man, if he could come to an end, there would be nothing. Outside man there is nothing.’
‘But the whole universe is outside us. Look at the stars! Some of them are a million light-years away. They are out of our reach for ever.’
‘What are the stars?’ said O’Brien indifferently. ‘They are bits of fire a few kilometres away. We could reach them if we wanted to. Or we could blot them out. The earth is the centre of the universe. The sun and the stars go round it.’
Winston made another convulsive movement. This time he did not say anything. O’Brien continued as though answering a spoken objection:
‘For certain purposes, of course, that is not true. When we navigate the ocean, or when we predict an eclipse, we often find it convenient to assume that the earth goes round the sun and that the stars are millions upon millions of kilometres away. But what of it? Do you suppose it is beyond us to produce a dual system of astronomy? The stars can be near or distant, according as we need them. Do you suppose our mathematicians are unequal to that? Have you forgotten doublethink?’
Winston shrank back upon the bed. Whatever he said, the swift answer crushed him like a bludgeon. And yet he knew, he knew, that he was in the right. The belief that nothing exists outside your own mind — surely there must be some way of demonstrating that it was false? Had it not been exposed long ago as a fallacy? There was even a name for it, which he had forgotten. A faint smile twitched the corners of O’Brien’s mouth as he looked down at him.
‘I told you, Winston,’ he said, ‘that metaphysics is not your strong point. The word you are trying to think of is solipsism. But you are mistaken. This is not solipsism. Collective solipsism, if you like. But that is a different thing: in fact, the opposite thing.
George Orwell, 1984
Wahrnehmung ist Falschnehmung
One of Brentano’s foremost aims in philosophy was to provide a new foundation for epistemology and logic as two closely related disciplines. He tried to achieve this by a systematic analysis of the mental phenomena involved in attaining knowledge and in drawing inferences. For Brentano knowledge is reached by judgements that are directly or indirectly evident, and logical inferences can contribute to our knowledge because they can make a judgement indirectly evident for us. Hence both epistemology and logic rely on a conception of judgements, how they differ from other mental phenomena, and how they are related to each other.
Brentano’s view of the nature of judgement differs significantly from other views that can be found in Aristotle, Kant, or Frege. In contrast to Aristotle, Brentano emphasizes the importance of existential judgements with only one term, and claims that predicative judgements are a special case of existential ones. In contrast to Kant, he emphasizes the difference between presentations and judgements, rejecting their unification in the single category “thinking”. In contrast to Frege, he holds that judgements do not require the existence of complete thoughts or propositions which have to be grasped before a judgement can be made. It is the mental act of judging, not its object or content, which is the bearer of truth-values. In view of these differences Brentano’s theory of judgement has been called existential (non-predicative), idiogenetic (non-reductionist), and reistic (non-propositional).
Today Brentano’s theory does not have many adherents. The now dominant view is that propositions or sentences are the objects of belief, and that judgements occur when beliefs are acquired, manifested, or changed. Logical inferences are then defined as relations between propositions or sentences, abstracting from the mental attitudes that go along with them. Although this anti-psychological approach is widely accepted today, there is still an open question concerning the order of explanation here: Are beliefs and judgements true because they are directed at true propositions, or should we say that propositions (and sentences) are true because they express true beliefs and judgements? Once this question is raised, Brentano’s theory of judgement remains an interesting alternative to the current mainstream in logic and epistemology.
Solipsism ( //) is the philosophical idea that only one’s own mind is sure to exist. The term comes from Latin solus (alone) and ipse (self). Solipsism as an epistemological position holds that knowledge of anything outside one’s own mind is unsure. The external world and other minds cannot be known, and might not exist outside the mind. As a metaphysical position, solipsism goes further to the conclusion that the world and other minds do not exist. Although the number of individuals sincerely espousing solipsism has been small, it is not uncommon for one philosopher to accuse another’s arguments of entailing solipsism as an unwanted consequence, in a kind of reductio ad absurdum. In the history of philosophy, solipsism has also served as a skeptical hypothesis.