| In our thinking...we attribute to this concept of the bodily object a significance, which is to high degree independent of the sense impression which originally gives rise to it. This is what we mean when we attribute to the bodily object "a real existence." ...By means of such concepts and mental relations between them, we are able to orient ourselves in the labyrinth of sense impressions. These notions and relations...appear to us as stronger and more unalterable than the individual sense experience itself, the character of which as anything other than the result of an illusion or hallucination is never completely guaranteed. -Einstein |