Bertrand Russell argues that this question is so significant in philosophy because of the implications of its answer. The idea that no other bodies exist means possibly no other minds may exist, leaving the individual facing the stark possibility of being completely alone in an imagined world (Russell, 2004, p9). I shall examine and criticise the reasoning of Moore and Berkeley to argue either side of the question and conclude that the best reason for believing in a material world is one largely based on simplicity. One of the most famous attempts at proving the existence of a physical world was made by G.E. Moore.
What he termed his ‘perfectly rigorous proof’ (Moore, 2002, p146) merely consisted of extending his hand and claiming he could see it so it must exist. In support of this argument, Stroud concedes that ‘the importance of the senses as a source or channel of knowledge seems undeniable’ (Stroud, 1984, p7) and also agrees that ‘the best proof we could possibly have of something’s existence would be to find it right before our eyes’ (Stroud, 1984, p85). However, it is certainly true that ‘what Moore says is no refutation of philosophical scepticism’ (Stroud, 1984, p126).
This means that his argument fails when one considers Descartes’ first and second stages of doubt as either his eyes could merely be deceiving him or he could just be dreaming that he sees his hand. Therefore I find it hard to subscribe to his angle of reasoning when it can be completely dismissed by the most basic and common form of philosophical scepticism. Yet another reason as to why this proof of a material world can be said to be inadequate is that it fails to offer a means for differentiating separate physical objects in the material world.
If objects are to be seen as entities in their own right, they need to exist independently from other entities and therefore need to be distinguished from those other entities. The contrasting view that there does not exist a material world outside of our minds was most strongly advocated by the idealist philosopher Bishop George Berkeley. His position was that ‘the world is ultimately spiritual and there is nothing beyond minds and their contents’ (Urmson, 1982, p33) and that ‘nothing can be known except what is in some mind’ (Urmson, 1982, p40).
He believed that material objects only exist because they are constantly being perceived by our senses and that we know nothing of the actual physicality of the object itself but instead we merely perceive it to have a physical aspect. For example, a table is not said to actually exist in the mind of the person that perceives it but merely the idea of the table exists and the difference between the two is indistinguishable to the particular mind involved. However, this raises the problem of different ways of perceiving the same objects.
If one of the basic characteristics of the mind is that it is independent and unlike other minds, then how can separate and distinct minds perceive a mere idea of a table in exactly the same way when there is no physical objective reference point to compare perceptions? Berkeley chose to attribute this consistency of perception by separate minds to a constant stream of communication with God. Thus God is also crucial in Berkeley’s ideas of the material world as instead of ideas of objects discontinuing to exist when people stop perceiving them, they instead are continually being perceived by God so the ideas of these objects remain intact.
Thus our perceptions are said to ‘constantly participate’ (Russell, 2004, p25) with God’s. However, I believe that this causes more problems for the idealist cause than it actually solves. Berkeley’s conviction in the existence of a God that is able to operate on a higher and separate level than other human minds appears to contradict part of his own convictions on this subject. A God that works on a separate level to other minds can’t be grouped with other minds, therefore is external to them.
Furthermore, God can’t be said to be dependent on any particular mind as one less mind just means one less perceptual message for God to send, thus God is both independent of and external from other minds. One could also argue that until a resolute proof of God’s existence can be provided, it cannot exist in the human mind, thus the human mind is unable to know for sure of God’s existence, so the idealist is forced to take the same leap of faith in trusting that God exists that the materialist has to take when relying on the existence of a mind-independent material world, as I shall explain now.
Thus even the staunchest believer in the existence of the mind-independent material world is forced to make concessions towards the idealist strain of thought. Russell chose to accept the Cartesian concept of the Cogito as the only absolute certainty in this regard, admitting that ‘we can never prove the existence of things other than ourselves and our private experiences’ (Russell, 2004, p12) whereas Stroud concedes that despite being entirely dependent on our senses for information, they still give us ‘no basis for believing one thing about the world around us rather than its opposite’ (Stroud, 1984, p32).
Kant similarly agreed that the ‘existence of a material world must be accepted merely on faith… we are unable to counter doubts with satisfactory proof’ (Stroud, 1984, p128), attributing a similar faith in materialism that Berkeley placed in God. However, I would agree with Russell when he states that the belief in a physical world is ‘instinctive’ (Russell, 2004, p14) for humans and that because it serves to ‘simplify and systematise our account of our experiences, there seems no good reason for rejecting it’.
Idealists would counter this by questioning whether mere convenience is a solid enough reason to believe in more than just the mind. Conversely, Schlick counters this by highlighting the significance of a potential change to this instinctive belief in physical entities when he argues that someone ‘who believes in a real external world will feel and work quite differently from one who merely aims at describing sensations’ (Schlick, 1981, p106).
In conclusion, the only good reasons to believe in a mind-independent material world are reasons of simplicity and continuity coupled with the lack of a feasible alternative. A change to this fundamental belief would completely disrupt the way humans live, although again idealists would doubt that the desire to maintain stability constitutes a ‘good’ reason for this belief. Bibliography John Cottingham, Descartes, Oxford, Blackwell, 1986. Reni??
Descartes, Meditations and Other Metaphysical Writings, London, Penguin, 2003. George Edward Moore, Philosophical Papers, London, Routledge, 2002. Bertrand Russell, The problems of philosophy, New York, Barnes and Noble Books, 2004. Moritz Schlick, Positivism and Realism in Essential Readings in Logical Positivism, Oxford, Blackwell, 1981. Barry Stroud, The significance of philosophical scepticism, Oxford, Clarendon, 1984. James Urmson, Berkeley, Oxford, Oxford University Press, 1982.