“It is easier to fight for one's principles than to live up to them.”

“The chief danger in life is that you may take too many precautions.”

“Trust only movement. Life happens at the level of events, not of words. Trust movement.”

“Follow your heart but take your brain with you.”

“إن التقدم العلمي ما هو إلا نتيجة لسعي البشر الدائم لتحسين أحوالهم عن طريق معرفة المزيد عن الكون المحيط بهم وتطوير قدراتهم على التعامل معه.”

“This quote begins here. A simple rule in dealing with those who are hard to get along with is to remember that this person is striving to assert his superiority; and you must deal with him from that point of view. This quote ends here.”

“He used to say to his melancholia patients:"You can be cured in fourteen days if you follow this prescription.Try to think every day how you can please someone.”