Broadly speaking, Protestants like to be good and have invented theology in order to keep themselves so, whereas Catholics like to be bad and have invented theology in order to keep their neighbors good. Hence, the social character of Catholicism and the individual character of Protestantism.

Every great idea starts out as a blasphemy.

A sense of duty is useful in work but offensive in personal relations. People wish to be liked, not to be endured with patient resignation.

Philosophy, from the earliest times, has made greater claims, and achieved fewer results, than any other branch of learning.

Do not feel certain of anything.

Our use of the phrase 'The Dark Ages' to cover the period from 600 to 1000 marks our undue concentration on Western Europe. [...] From India to Spain, the brilliant civilisation of Islam flourished. What was lost to Christendom at this time was not lost to civilisation, but quite the contrary. [...] To us it seems that West-European civilisation is civilisation, but this is a narrow view.

It will be said that the joy of mental adventure must be rare, that there are few who can appreciate it, and that ordinary education can take no account of so aristocratic a good. I do not believe this. The joy of mental adventure is far commoner in the young than in grown men and women. ...It is rare in later life because everything is done to kill it during education.