There is another consideration that affects parallelism alone. Since the theory credits each of the two series with a closed and sufficient causal sequence, each of which excludes the other, it does away with causality altogether. That the one line runs parallel with the other excludes the idea that a unique system of laws prevails, determining the character and course of each line. One of the two lines must certainly be dependent, and one must lead. Otherwise there can be no distinctness of laws in either. Let us recall our illustration of the cloud shadows once more; the changing forms of the shadows correspond point for point with those of the clouds only because they are entirely dependent upon them. We may illustrate it in this way: a parallel may be drawn to an ellipse, it also forms a closed curved line. But it is by no means again an ellipse, but is an entirely dependent figure without any formula or law of its own. Parallelism must make one of its lines the leading one, which is guided and directed by an actual causal connection within itself. The other line may then run parallel with this, but its course must certainly be determined by the other. And as the line of corporeal processes, with its inviolable nexus of sequences, is not easily broken, parallelism, after many hard words against materialism, frequently returns to that again or becomes inconsistent. But if one says that the two aspects of phenomena are only the forms of one fundamental phenomenon, that means taking away actual causality from both alike, and leaving only a temporal sequence. For then the actually real is the hidden something that throws the cloud-shadows to right and left. But in the sequence of shadows there is no causal connection, only a series of states succeeding one another in time, and this points to a causal connection elsewhere. It is easy enough to find examples to prove that the mental in us influences the bodily. But the most convincing, deepest and most trustworthy of these are not the voluntary actions which are expressed in bodily movements, nor even the passions and emotions, the joy which makes our blood circulate more quickly, and the shame which brings a flush to our foreheads, the suggestions which work through the mind towards the reviving, vitalising or healing of the body, but the cold and simple course of logical thought itself. Through logical thinking we have the power to correct the course of our conceptions, to inhibit, modify, or logically direct the natural course, as it would have been had it been brought about by our preceding physiological and psychical states, if they were dominant and uncontrolled. But if so, then we must also have the power, especially if it be widely true that physiological states correspond to psychical states, to influence, inhibit, modify the nerve-processes in our brain, or to liberate entirely new ones, namely, those that correspond to the corrected conceptions.