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2 Realism & anti-realism
2.1 Reality really exists
Although many people are unaware, virtually all mankind thinks in terms of what is called philosophical realism. Someone who sees a tree is convinced the tree doesn't only manifest itself in his mind, but beyond a real tree exists . A mountain, a river, the clouds one sees, all really exists, one thinks to know. There is no doubt about the real existence of music, a tasty plate of spaghetti, delicious spring weather or a completely destroying hurricane. Believers, at least the real, do not doubt the real existence of their god or gods. In science too, realism is the dominant idea: for a physicist in his study room, the electron, the pi-meson, the neutrino and nowadays also the vibrating strings from string theory are just as real as his son's soccer ball that just passed through the window or the too large grown Cage Tiger in his pond.
There are things too that do not really exist. If you dreamed at night, you are certain the dream did not actually take place. When watching a war film people usually do not pull back with an emergency supply of beans in the stairs cupboard arranged as a bomb shelter.[1]
So there are many things that really exist while at the same time we experience 'things' that obviously do not exist.
2.2 What does 'existence' mean?
What is actually meant by that, real existence? In order to give content to the concept, philosophers use different descriptions, which often means a thing really exists if one can speak about it independently of one's consciousness. One can talk about a tree, even though one does not know that tree itself. You can communicate about the tree without changing anything about it, whatever you say about it. If the tree disappears from yours field of view or consciousness, temporarily or even forever, nothing changes about the tree itself, in contrast to a dream, which immediately ceases to exist as soon as you wake up. At most, you remember for some time what happened in that dream, and, if written down quickly, the dream continues to exist in a certain sense, but you are very aware the dream was not a reality. Does a movie, at least that which happens in the film, still exist if you does not think about it anymore? Of course, a distinction must be made between the film as a material object, formerly a role of celluloid, nowadays some form of digital memory, which of course really exists and the film as a story or series of events that one experiences when the film is shown.
No, normal people do not doubt the existence of a real world alongside the non-existent world of dreams and fantasies. Those who say they doubt the existence of a real world are either crazy or philosophers. Since early times sceptical philosopher have great difficulty with claims that things really exist in the world. They asked how to know that behind the experienced tree a real, material tree exists independent of the consciousness. After all, knowing the tree is something which only takes place in consciousness, caused by sensory impressions of those and other trees and of what people - parents, teachers - have transferred.
There is no direct relationship between the real existing tree and the consciousness, the only connection which takes place runs via the intermediary role of the senses. Suppose someone doubts whether the tree he sees really exists. What he can do is walking towards it, feel, look, and maybe hear and smell it as well. He can also talk to other people about the tree, understanding they are experiencing the same tree. Even then one is not essentially further: it is all only about information acquired through sensory processes, processes which take place within the body and the mind. This applies not only to the sensory impressions from the tree itself, just as well to the linguistic expressions of those with whom one converses about it. It may be assumed the real tree is the cause of those sensory processes, but being sure that it is more than a belief, one cannot.
2.3 Realism, a plausible but untenable theory
Descartes argued a person cannot trust his own observations because they may been manipulated by a demon. Later in life he stated one cannot trust his observations because it's possible one only dreams there is a real world. Also well-known is the thought experiment of the brain in a vat. Imagine that a handsome surgeon cuts brains out of a body and connects all severed neurons through fine wires to an extremely powerful computer which generates exactly the same signals as those were delivered by the body before. In that case, the brains would experience exactly the same as if they were still functioning in the body and thus - now obviously wrongly - conclude there is a real world which causes the images, sounds and the like. That in this case the illusion of a real world in fact is created by a well-programmed computer, the isolated brain cannot, in essence, determine.
Although throughout the ages philosophers have tried to find a reasoning to conclude strictly logically the material world really exists beyond our consciousness, it must be noted that those attempts ultimately never succeeded. The (philosophical) idealists or constructivists have concluded from this that the whole world does not really exist, it's just a product of the creative human spirit, a combination of ideas.
In the philosophy of science, the positivists have taken the position that the visible things and phenomena really exist, while it's a form of unclean thinking to consider as real existent such things as electrons, which are described by the physical theory but cannot be observed directly. They regard it as a form of metaphysics, which must be banished from science. However, the starting point of the positivists, that visible things really exist, is itself not a result of empirical research either, thus also a form of metaphysics.
In the same discipline, realists postulate the existence of an external objective reality in which an objectivity principle determines what is actually objective or subjective. That principle, however, is in conflict with realism itself, because it does not stem from objective observations, just from human interpretation. Also the later sometimes chosen way out by talking about the probability a certain theory is in accordance with the truth is fundamentally no solution. The view that the empirical sciences offer a description of reality or truth finely remains a non-provable, metaphysical theory.
However, although it is logically not possible to conclude from observations there is a real reality, the realists have a strong point. If you didn't believe in a world independent of the human mind, how to explain you could communicate with others about that world. How to explain that one understands each other immediately when speaking about a certain object and the world is experienced by everyone as - relatively - stable. When I fall asleep tonight, my consciousness disappears and so does the world I experience. On awakening the next morning the same world is present again in the same form, with at most small changes, such as the time the clock indicates, the morning sun instead of evening light and the like. If I leave my house and another one moves in, he will experience exactly the same house that I left behind. If we call each other and he tells what the house looks like, I recognize everything without difficulty. Apparently his world is the same as mine. How could such be explained if there was no real home independent from our mind?
However, this question also has a downside. There are many things - think of such concepts as mother love or the French language - which are created exclusively by the human mind and which in a sense are experienced as being truly existing. If you rank concepts on a 'reality scale', for example the triad: tree - mother love - dream - then nobody doubts the concept at one end really exists, that on the other end certainly does not. But where is the border and above all: on what grounds do you think you can define a boundary? Reality does not teach it to us. On the basis of observations it's impossible to determine which aspects belong to objective reality and which only belong to reality as appearing to man. It is not only practically but also fundamentally impossible to derive criteria from reality that determine the boundary between reality and fantasy.
3.4 What should be demanded of philosophy?
One may wonder if there is a problem. What is wrong when most people think in terms of a real existing world? Generally nothing. However, for a consistent philosophical theory intending to make the perceived world transparent, it is extremely unsatisfactory.
Firstly, it seems neat to use Ockham's razor as a general starting point: "Entities must not be multiplied beyond necessity". In this context, the principle implies that one should not presume the existence of a real world if experiences also can be explained in a simpler way. Secondly, a wrong presumption can block the thinking in a dramatic way. Many historical examples illustrate this. What was wrong with the idea that the sun and the planets move around the earth, as was generally believed until the late Middle Ages? Why not believe that there is a heat substance or think that there is a special substance, called ether, through which electromagnetic waves propagate? History has shown that the maintenance of this kind of hypotheses, created by common sense, often block further development of physical theory, developments that could only break through once the old hypotheses had been abandoned. Any superfluous opinion, no matter how obvious, can prevent further development of the understanding of things.
The existence of a real world is such a superfluous view. Nothing can be explained with it, nor can any substantiation be given for it. As soon as one realises this, one views the philosophical literature with different eyes, and sees that a great deal of philosophy consists of convulsive and barren attempts to create an objective reality from the human, subjective experiences.
But the reverse idealistic position, the assertion that reality does not exist, doesn't add anything either, and is also affected by the chilly operation of Ockham's razor. The only position remaining is that which Wittgenstein seems to choose in his later work: 'Whereof one cannot speak thereof one must be silent'.
The remaining question is what could be the profit of this approach. What can be better explained without the hypothesis of an underlying reality than is possible with it? The answer to this question will become clear in this book.
However, asking for the explanatory power of a philosophical theory is an unusual requirement. Many philosophers see philosophy as a view which should differ per philosopher, the fact that most philosophical theories are in no way related to each other is often seen as a specific, perhaps essential, feature of the philosophical domain.
However, such a position does not seem fruitful. A good philosophical theory should expose underlying structures which provide insight into the coherence of things, through which phenomena are understood and explained. Any theory that does not at least meet this criterion can be forgotten without sorrow.
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[1] During the cold war in the Netherlands an advice from the Protection of Population in case of an atomic attack