At one point, ‘sympathy’ seems to have been (largely?) a name for a physical phenomenon, and a certain sort of explanation of that phenomenon (see this earlier post on More and Mersenne). Over time, ‘sympathy’ seems to have become more exclusively used to describe a psychological phenomenon (e.g., Hume, Smith). I’m curious about how sympathy moved from being one thing to the other. Even Hume uses an ancient example of physical sympathy to illustrate the psychological sort: “As in strings equally wound up, the motion of one communicates itself to the rest; so all the affections readily pass from one person to another, and beget correspondent movements in every human creature” (Treatise 188.8.131.52). Well before Hume, however, we seem to find find Margaret Cavendish, in an early poem, explicitly making the connection between the two sorts of sympathy.
According as the Notes in Musicke agree with the Motions of the Heart, or Braine, Such Passions are produced thereby.
IN Musicke, if the Eighths tun’d Equall are,
If one be strucke, the other seemes to jarre.
So the Heart-strings, if equally be stretch’d,
To those of Musick, Love from thence is fetch’d.
For when one’s strucke, the other moves just so,
And with Delight as evenly doth go.
(Margaret Cavendish, Poems and Fancies (London, 1653), p.40. )