English En
  • Deutsche De
  • English En
  • Français Fr
  • Русский Ru

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our marketing and analytics partners who may combine it with other information you've provided to them or which they've separately collected from you. You also may to see our Privacy Policy. By clicking the OK button below, you accept our cookies.

Authors:

The view is often defended that sciences should be built up on clear and sharply defined basal concepts. In actual fact no science, not even the most exact, begins with such definitions. The true beginning of scientific activity consists rather in describing phenomena and then in proceeding to group, classify and correlate them.

Sigmund Freud