Some lofty concepts, like space and number, involve truths remote from the category of causation; and here we must be content, as Aristotle says, if the mere facts be known. But natural history deals with ephemeral and accidental, not eternal or universal things; their causes and effects thrust themselves on our curiosity,and become the ultimate relations to which our contemplation extends.- D'Arcy Wentworth Thompson (1860-1948)
