As long as one stops here everything seems to fit beautifully. But we must go over the argument once more from the beginning. Hitherto I have used, as my starting-point, the object, i.e., the external percept of which up to now, from my naïve standpoint, I had a totally wrong conception. I thought that the percept, just as I perceive it, had objective existence. But now I observe that it disappears with my act of perception, that it is only a modification of my mental state. Have I, then, any right at all to start from it in my arguments? Can I say of it that it acts on my soul? I must henceforth treat the table of which formerly I believed that it acted on me, and produced an idea of itself in me, as itself an idea. But from this it follows logically that my sense-organs, and the processes in them are also merely subjective. I have no right to talk of a real eye but only of my idea of an eye. Exactly the same is true of the nerve paths, and the brain processes, and even of the process in the soul itself, through which things are supposed to be constructed out of the chaos of diverse sensations. If assuming the truth of the first circle of argumentation, I run through the steps of my cognitive activity once more, the latter reveals itself as a tissue of ideas which, as such, cannot act on one another. I cannot say that my idea of the object acts on my idea of the eye, and that from this interaction results my idea of colour. But it is necessary that I should say this. For as soon as I see clearly that my sense-organs and their activity, my nerve- and soul-processes, can also be known to me only through perception, the argument which I have outlined reveals itself in its full absurdity. It is quite true that I can have no percept without the corresponding sense-organ. But just as little can I be aware of a sense-organ without perception. From the percept of a table I can pass to the eye which sees it, or the nerves in the skin which touches it, but what takes place in these I can, in turn, learn only from perception. And then I soon perceive that there is no trace of similarity between the process which takes place in the eye and the colour which I see. I cannot get rid of colour sensations by pointing to the process which takes place in the eye whilst I perceive a colour. No more can I re-discover the colour in the nerve- or brain-processes. I only add a new percept, localised within the organism, to the first percept which the naïve man localises outside of his organism. I only pass from one percept to another.