English

Noun

animal spirits pl ‎(plural only)

1. (medicine, now historical) The theorized ‘spirits’ or physiological principles which allowed for sensation and voluntary movement. [from 15th c.]
   • 1621, Robert Burton, The Anatomy of Melancholy, vol.I, New York 2001, p.253:

     This is likewise evident in such as walk in the night in their sleep, and do strange feats: these vapours move the phantasy, the phantasy the appetite, which moving the animal spirits causeth the body to walk up and down as if they were awake.

   • 1723, Charles Walker, Memoirs of Sally Salisbury, VI:

     His Brains will be found situated at the Head of the Os Pubis: His Animal Spirits acting more vigorously in that Part, than in the Upper Region.

   • 1759, Lawrence Sterne, The Life and Opinions of Tristram Shandy, Gentleman, Folio Society 2005, p. 19:

     you have all, I dare say, heard of the animal spirits, as how they are transfused from father to son &c. &c.—and a great deal to that purpose:– Well, you may take my word, that nine parts in ten of a man's sense of his nonsense, his successes and miscarriages in this world depend upon their motions and activity [...].

2. Liveliness, vivacity, a happy tendency to action. [from 18th c.]
   • 1813, Jane Austen, Pride and Prejudice, Plain Label 1975, p. 63:

     She had high animal spirits, and a sort of natural self-consequence, which the attention of the officers, to whom her uncle's good dinners, and her own easy manners recommended her, had increased into assurance.

   • 1936, John Maynard Keynes, The General Theory of Employment, Interest, and Money, page 161:

     Most, probably, of our decisions to do something positive, the full consequences of which will be drawn out over many days to come, can only be taken as a result of animal spirits — of a spontaneous urge to action rather than inaction, and not as the outcome of a weighted average of quantitative benefits multiplied by quantitative probabilities.

3. (economics) After Keynes (citation 1936, above), the emotional and intuitive factors that drive business decisions whether to make investment gambles. [from 20th c.]
   • 1975, Hyman P. Minsky, John Maynard Keynes‎, page 11:

     This flaw exists because the financial system necessary for capitalist vitality and vigor — which translates entrepreneurial animal spirits into effective demand for investment — contains the potential for runaway expansion, powered by an investment boom.

   • 2005, Roger S. Frantz, Two minds: intuition and analysis in the history of economic thought‎, page 91:

     The existence of animal spirits does not imply that "irrational psychology" is the controlling factor in business and economics.

   • 2006, Robert J. Shiller, Irrational Exuberance‎, page 233:

     One of John Maynard Keynes's most famous terms, "animal spirits," is another name for much the same concept as irrational exuberance‎