All great undertakings are achieved through mighty obstacles. Keep up the deepest mental poise. Take not even the slightest notice of what puerile creatures may be saying against you.
Abridge your hopes in proportion to the shortness of the span of human life; for while we converse, the hours, as if envious of our pleasure, fly away: enjoy, therefore, the present time, and trust not too much to what to-morrow may produce.
No matter how we may single out a complex from nature...its theoretical treatment will never prove to be ultimately conclusive... I believe that this process of deepening of theory has no limits.