The doctrine of a closed physical universe by Titus Rivas The notion of a physically closed universe is central to the philosophical current of of physicalism. In general, physicalism is (following a definition I have adopted from John Beloff) the theory that everything in the physical universe happens solely and exclusively because of physical factors. In other words, there are no non-physical causes and if anything non-physical exists, it is by definition utterly causally powerless, i.e. it has no impact whatsoever and it is caused itself by physical factors alone. In this short paper I will explore the two kinds of arguments that are given for this remarkable, existentially unattractive and yet very influential view. Empirical argument for a closed physical universe The main reason why scientists believe in a closed physical universe is the physical evidence they have collected for the universality of physical laws and the conservation of energy. According to such scientists there is no evidence for any non-physical factors that would go against the supposedly closed nature of physical reality. For them, this is not so much an apriori insight, but a matter of fact. I think we should realise that the empirical reason could only be strong if there were absolutely no empirical evidence for any non-physical factors. However, there really is quite a lot of such evidence, especially from parapsychological studies into psychokinesis. Any open-minded empirical scientist eager to believe in a closed physical university should give such evidence a lot of special attention as it just might falsify his cherished theory. Analytical argument for a closed physical universe More serious than the empirical reason to believe in a closed physical universe is of course the claim that it would be illogical to believe in an open physical universe that could be affected by non-physical factors. We should not confuse this argument with the 'logical' argument that believing in an open universe would be incompatible with empirical data. This is because a logical deduction from empirical data can ultimately be seen as an empirical argument (all good arguments should be rational, but this does not mean that all arguments are purely analytical). The structure of the analytical argument for a closed physical reality amounts to the claim that it would require 'magic', i.e. that it would clash with the basic ontological way we conceive of reality. Now, this argument is only important if we can be sure that what we think about physical reality and its relation to non-physical entities is true. If not, the argument is circular, meaning that it presupposes what it desires to prove. We actually cannot be sure, because there is no conclusive apriori reason to suppose that the physical world cannot be influenced by non-physical factors. Therefore, the argument really begs the question and may be translated as: "we should not believe in an open physical world because we do not believe in an open physical world". It is like saying "we should believe in God, because we believe in God" or indeed "we should believe it can only rain during September, because we believe it can only rain during September". If every scholar thought this way, no intellectual progress would ever be possible. The way things are may only be magical or miraculous as compared to our believe systems; from an objective viewpoint they simply are the way they are. However, there is an even more fatal blow against the analytical argument in favour of a closed physical universe. If we accept the existence of non-physical entities such as qualitative subjective experiences and if we accept that we are able to know that they exist and if we also accept that we are able to talk and write about them in a meaningful, realistic way, it must mean that these non-physical entities have had a causal impact, not only on our cognitive apparatus and memory bank, but also on our motor system as is demonstrated whenever we express our conceptual knowledge of subjective experiences as stored in our conceptual memory via speach and writing. It is analytically absurd to acknowledge the knowability of the existence of subjective experiences and at the same time deny that they have an impact on our physical actions. Either one accepts the knowable existence of subjective experiences (or other non-physical entities) and our capacity to physically use symbols to communicate about these in a meaningful way, or one should abandon the notion of knowable non-physical subjective experiences altogether. Anyone who believes there are non-physical aspects to his or her own subjective awareness which he can meaningfully think and talk about should therefore abandon the all too popular notion of a closed physical universe for a purely analytical reason alone. Logically speaking, a closed physical universe simply does not make sense. Also see: Exit Epiphenomenalism Nijmegen, 2007.