Two Quotes
Critique of Practical Reason conclusion (1788) (translation by Lewis White Beck)
Merciless criticism and independent thinking are the two necessary traits of revolutionary thinking.
Bhagat Singh, Bhupendra Hooja, Democratic Youth Federation of India (2007). “Bhagat Singh, on the path of liberation”
Make a habit of two things: to help; or at least to do no harm.
Epidemics bk. 1, ch. 11
Quoted in Proceedings of the London Mathematical Society, 26 May 1921