Our considerations, starting from certain statements made by some leading scientific thinkers of our time, have helped us not only to confirm the truth inherent in these statements, but to recognize the facts stated by them as being the outcome of certain laws of evolution and thereby having an historic necessity. This, however, does not mean that man's scientific labours, carried out under the historically given restrictions, great and successful as these labours were and are, have not led to calamitous effects such as we found indicated by Professor Carrel. The sciences of matter have led man into a country that is not his, and the world which he has created by means of scientific research is not only one in which he is a stranger but one which threatens to-day to deprive him of his own existence. The reason is that this world is essentially a world of active forces, and the true nature of these is something which modern man, restricted to his onlooker-consciousness, is positively unable to conceive. We have taken a first step in diagnosing man's present spiritual condition. A few more steps are required to lead us to the point where we can conceive the therapy he needs. 1 This address and another by the same author are published together under the common title, Wandlungen in den Grundlagen der Naturwissenschaft ('Changes in the foundations of Natural Science'). Heisenberg's name has become known above all by his formulation of the so-called Principle of Indeterminacy. 2 See, in this respect, Faust's dispute with Mephistopheles on the causes responsible for the geological changes of the earth. (Faust II, Act 4) 3 See also Eddington's more elaborate description of this fact in his New Pathways in Science. The above statement, like others of Eddington's, has been Contested from the side of professional philosophy as logically untenable. Our own further discussion will show that it accords with the facts. 4 Both words, kinematics and kinetics, are derivatives of the Greek word kinein, to move. The term 'kinematic' is used when motion is considered abstractly without reference to force or mass. Kinetics is applied kinematics, or, as pointed out above, dynamics treated with kinematic concepts. 5 These last statements will find further illustration in the next two chapters. 6 First published in 1917 in his book Von Seelenrätseln. 7 Homer's men still think with the diaphragm (phrenes). Similarly, the ancient practice of Yoga, as a means of acquiring knowledge, shows that at the time When it flourished man's conceptual activity was felt to be seated elsewhere than in the head. 8 This must not be confused with the fact that a smell may evoke other memories by way of association.