Berkeley thought this was scepticism. If we place the real beyond the reach of all experience then scepticism is unavoidable. The doctrine of material substance according to Berkeley had precisely this effect. He claimed to defend common sense against sceptical challenges. Various arguments have come on his claim to defend common sense.Berkeley argues that if the object causes the sensation, then if that object were removed, we would be away from the sensible world. We do not have to presuppose the reality of external material substances.
Berkeley held that what we really perceive is as we perceive it to be. We merely perceive sensible objects, which are a collection of sensible qualities. These sensible qualities in turn are nothing but the ideas ingrained in the mind of the perceiver. This can be further explained by the example of heat. The heat has its own qualities. the heat has a certain temperature. If we dip one hand in chilled water and the other in tepid water and then both together in a bowl of hot water, what is the difference?
One hand feels hot and the other cold or less hot. If the heat or the hot water creates the sensation, it should have been the same on both hands. This clearly explains Berkeley’s theory that all perceptions are mere ideas of the mind. He totally disagrees that anything exists external to our mind and this is aptly confirmed by this example of heat.Berkeley states that we cannot perceive of any sensible object existing independently of a perceiver. Suppose one is asked to think of a tree in the middle of a dense forest.
If one can conceive such a thing, then it confirms that he has some previous idea about it in the mind. This means that irrespective of the existence of the tree, one can perceive it based on ideas of the mind. Thus, the object – the tree or the forest has not created the sensation. the table does create the sensation of brownness to appear before our eyes. .