"Every evening, I come home tired and have just enough energy to fill out the endless tax forms, to pay bills, not to let my house neglected and to hear the radio concert for an hour."

"Mountains were once my big adventure but is is over since a long time; I still dream from the wonderful days sometimes, read also a few pages from a mountain book. But the thought of doing again active mountain climbing has faded."

"I have a good idea every two years. Give me a topic, I will give you the idea!"

"I soon became convinced... that all the theorizing would be empty brain exercise and therefore a waste of time unless one first ascertained what the population of the universe really consists of."