If we wish to think with the course of the universe and not against it, we must not start our considerations with the state of (relative) rest or uniform motion in a straight line and derive our definition of force from the assumption that there is a primary 'force-free' state which is altered under the action of some force, but we must arrange our definitions in such a way that they end up with this state. Thus Newton's first law, for instance, would have to be restated somewhat as follows: No physical body is ever in a state of rest or uniform motion in a straight line, unless its natural condition is interfered with by the particular action of some force. Seen dynamically, and from the aspect of the universe as an interrelated whole, all aggregations of mass are the manifestation of certain dynamic conditions within the universe, and what appears to us as a change of the state of motion of such a mass is nothing but a change in the dynamic relationship between this particular aggregation and the rest of the world. Let us now see what causes of such a change occur within the field of our observation. * In modern textbooks the nature of the cause of physical movement is usually defined as follows: 'Any change in the state of movement of a portion of matter is the result of the action on it of another portion of matter.' This represents a truth if it is taken to describe a certain kind of causation. In the axiomatic form in which it is given it is a fallacy. The kind of causation it describes is, indeed, the only one which has been taken into consideration by the scientific mind of man. We are wont to call it 'mechanical' causation. Obviously, man's onlooker-consciousness is unable to conceive of any other kind of causation. For this consciousness is by its very nature confined to the contemplation of spatially apparent entities which for this reason can be considered only as existing spatially side by side. For the one-eyed, colour-blind spectator, therefore, any change in the state of movement of a spatially confined entity could be attributed only to the action of another such entity outside itself. Such a world-outlook was bound to be a mechanistic one. We cannot rest content with this state of affairs if we are sincerely searching for an understanding of how spirit moves, forms, and transforms matter. We must learn to admit non-mechanical causes of physical effects, where such causes actually present themselves to our observation. In this respect our own body is again a particularly instructive object of study. For here mechanical and non-mechanical causation can be seen working side by side in closest conjunction. Let us therefore ask what happens when we move, say, one of our limbs or a part of it.