Ancient Greek philosophical writings on friendship cast a long shadow in Western culture. The year 1508 saw the publication of Erasmus' distillation of the wisdom of the ancient Greeks and Romans in his Adages. The very first adage Erasmus provides is a philosophical pronouncement on friendship: “friends hold all things in common” – a saying attributed to Pythagoras. Erasmus notes:

In a further expansion of this circle of like-minded friends, Erasmus goes on to suggest that the Pythagorean communitarianism is nothing less than a foreshadowing of the community of life and property that Christ taught.

In 1644 the young Isaac Newton began a new notebook of reflections during his studies at Cambridge. At the top of the first page he wrote, “Amicus Plato, amicus Aristoteles, magis amica veritas.” The slogan, invoked by those enamoured of the new science, alludes to a remark in Aristotle's Nicomachean Ethics in which he somewhat reluctantly criticizes Plato's theory of Forms. Aristotle notes that since “philosophy” means love of wisdom, philosophers must criticize the mistaken views even of friends “for while both are dear, piety requires us to honour truth above our friends (NE 1096a15–17, our trans.)”.