Quotations about   custom

In the course of my travels I remarked that all those whose opinions are decidedly repugnant to ours are not in that account barbarians and savages, but on the contrary that many of these nations make an equally good, if not better, use of their reason than we do. I took into account also the very different character which a person brought up from infancy in France or Germany exhibits, from that which, with the same mind originally, this individual would have possessed had he lived always among the Chinese or with savages, and the circumstance that in dress itself the fashion which pleased us ten years ago, and which may again, perhaps, be received into favor before ten years have gone, appears to us at this moment extravagant and ridiculous. I was thus led to infer that the ground of our opinions is far more custom and example than any certain knowledge.

[Et depuis, en voyageant, ayant reconnu que tous ceux qui ont des sentiments fort contraires aux nôtres ne sont pas pour cela barbares ni sauvages, mais que plusieurs usent autant ou plus que nous de raison; et ayant considéré combien un même homme, avec son même esprit, étant nourri dès son enfance entre des Français ou des Allemands, devient différent de ce qu’il seroit s’il avoit toujours vécu entre des Chinois ou des cannibales, et comment, jusques aux modes de nos habits, la même chose qui nous a plu il y a dix ans, et qui nous plaira peut-être encore avant dix ans, nous semble maintenant extravagante et ridicule; en sorte que c’est bien plus la coutume et l’exemple qui nous persuade, qu’aucune connaissance certaine.]

René Descartes (1596-1650) French philosopher, mathematician
Discourse on Method [Discours de la méthode], Part 2 (1637) [tr. Veitch (1901)]
    (Source)

(Source (French)). Alternate translations:

I further recognized in the course of my travels that all those whose sentiments are very contrary to ours are yet not necessarily barbarians or savages, but may be possessed of reason in as great or even a greater degree than ourselves. I also considered how very different the self-same man, identical in mind and spirit, may have become, according as he is brought up from childhood amongst the French or Germans, or has passed his whole life amongst Chinese or cannibals. I likewise noticed how even in the fashions of one's clothing the same thing that pleased us ten years ago, and which will perhaps please us once again before ten years are passed, seems at the present time extravagant and ridiculous. I thus concluded that it is much more custom and example that persuade us than any certain knowledge.
[tr. Haldane & Ross (1911)]

Since then I have recognized through my travels that those with views quite contrary to ours are not on that account barbarians or savages, but that many of them make use of reason as much or more than we do. I thought, too, how the same man, with the same mind, if brought up from infancy among the French or Germans, develops otherwise than he would if he had always lived among the Chinese or cannibals; and how, even in our fashions of dress, the very thing that pleased us ten years ago, and will perhaps please us again ten years hence, now strikes us as extravagant and ridiculous. Thus it is custom and example that persuade us, rather than any certain knowledge.
[tr. Cottingham, Stoothoff (1985)]