For the religious the holy is truth, for the philosophic the truth is holy.

Faith is essentially intolerant ... essentially because necessarily bound up with faith is the illusion that one's cause is also God's cause.

I would rather be a devil in alliance with truth, than an angel in alliance with falsehood.

He only is a true atheist to whom the predicates of the Divine Being - for example, love, wisdom and justice - are nothing.

My only wish isto transform friends of God into friends of man, believers into thinkers, devotees of prayer into devotees of work, candidates for the hereafter into students of the world, Christians who, by their own procession and admission, are half animal, half angel into persons, into whole persons.

The first and highest law must be the love of man to man. Homo homini Deus est - this is the supreme practical maxim, this is the turning point of the world's History.

The joys of theory are the sweetest intellectual pleasures of life