"And though these researches may appear painful and fatiguing, it is with some minds as with some bodies, which being endowed with vigorous and florid health, require severe exercise, and reap a pleasure from what, to the generality of mankind, may seem burdensome and laborious."
— Hume, David (1711-1776)
First published as Philosophical Essays Concerning Human Understanding (London: Printed for A Millar, 1748). <Link to ECCO><Link to ECCO-TCP><Link to 1748 edition in Google Books> "Second edition" in 1750, "third edition" in 1756. First titled An Enquiry Concerning Human Understanding in 1758.
In ECCO-TCP, see also Essays and Treatises: on Several Subjects. By David Hume, Esq, 4 vols. (London: Printed for A. Millar; and A. Kincaid and A. Donaldson, at Edinburgh, 1760). <Link to vol. III>
Text from David Hume, Enquiries Concerning Human Understanding and Concerning the Principles of Morals. 3rd edition. Ed. L. A. Selby-Bigge; P. H. Nidditch (Oxford: Oxford University Press, 1975). Note, Nidditch reproduces the the second volume of the posthumous edition of 1777, which he has collated with the preceding 1772 edition.