Mankind is an inventive species; and where an invention is obvious and absolutely necessary, it may as properly be said to be natural as any thing that proceeds immediately from original principles, without the intervention of thought or reflection.
 David Hume, A Treatise of Human Nature (1738). copy citation

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Author David Hume
Source A Treatise of Human Nature
Topic invention mankind
Date 1738
Language English
Reference
Note
Weblink http://www.gutenberg.org/files/4705/4705-h/4705-h.htm

Context

“To avoid giving offence, I must here observe, that when I deny justice to be a natural virtue, I make use of the word, natural, only as opposed to artificial. In another sense of the word; as no principle of the human mind is more natural than a sense of virtue; so no virtue is more natural than justice. Mankind is an inventive species; and where an invention is obvious and absolutely necessary, it may as properly be said to be natural as any thing that proceeds immediately from original principles, without the intervention of thought or reflection. Though the rules of justice be artificial, they are not arbitrary. Nor is the expression improper to call them Laws of Nature; if by natural we understand what is common to any species, or even if we confine it to mean what is inseparable from the species.” source