50. You may ask me, what is the soul separated from the body? What will it perceive and know of itself, when it exists _alone_? As though it did not now perceive and know _alone_, or as though the organs, which it uses, could perceive or think. Does it, perchance, know how it uses them, or even know otherwise than by experience that it uses them at all? Is it not alone in the depths of its activity with its thoughts and the acts of its will, its sentiments, its joy and its sadness, its pleasures and its pains? Say, then, that perhaps we do not form sufficiently clear ideas of the _mode_ of consciousness which we shall have of ourselves after this life; say that perhaps other intuitions of our self are possible; but do not imagine the soul as inconceivable alone. Leave me thought, will, sentiment, all that is internally present to my consciousness, to find myself; I ask no more. Give me communication with other beings, which affect me or are affected by me, which transmit to me thoughts and wills, which cause me pleasure or pain; I need nothing more in order to have a world which I can very well conceive. I am ignorant of the quality of the things, not of their possibility: the soul changes its state, not its nature. CHAPTER IX. KANT'S OPINION OF THE ARGUMENTS PROVING THE SUBSTANTIALITY OF THE SOUL. 51. The psychological arguments in favor of the substantiality of the soul are mere paralogisms, in Kant's opinion; although they prove an ideal substance, they can never lead to a real substance. Besides the arguments with which this philosopher attacks the psychological proof of the substantiality of the soul, he had also a personal argument, which, considering the weakness of the human heart, was very powerful. He had either to place the substantiality of the soul in doubt, or else consent to the ruin of his whole system. "It would be," he says, "a great and even the only stumbling-block in our whole _critique_, if there were a possibility of demonstrating _a priori_ that all thinking beings are in themselves simple substances, and (which is a consequence of the principle of this demonstration) are inseparably accompanied by personality and the consciousness of their existence distinct from all matter. For, in this case, if we had taken a single step out of the world of the senses, we should have entered into the field of the _noumena_, and no one would dispute our right to extend farther into it, to build in it, and, according to each one's good luck, to take possession of it."[43] [43] Von den Paralogismen der reinen Vernunft, p. 297.