There is, however, no universal recipe for scientific advance. It is a matter of groping forward into terra incognita of the outer world by means of methods which should be adapted to the circumstances.

[In geology,] As in history, the material in hand remains silent if no questions are asked. The nature of these questions depends on the "school" to which the geologist belongs and on the objectivity of his investigations. Hans Cloos called this way of interrogation "the dialogue with the earth," "das Gesprach mit der Erde."

In our lives we have known hell and heaven; the final balance, however, is that we helped pave the way to dynamic harmony in this earthly house. That, I believe, is the meaning of this live.

Geology differs from physics, chemistry, and biology in that the possibilities for experiment are limited.

There is, however, no universal recipe for scientific advance. It is a matter of groping forward into terra incognita of the outer world by means of methods which should be adapted to the circumstances.

The subjective element in geological studies accounts for two characteristic types that can be distinguished among geologists. One considering geology as a creative art, the other regarding geology as an exact science.

As geology is essentially a historical science, the working method of the geologist resembles that of the historian. This makes the personality of the geologist of essential importance in the way he analyzes the past.