free variation in imagination

 cannot be varied without destroying the object as an instance of its kind.

This intuition of essences proceeds via what Husserl calls 'free variation in imagination.' We imagine variations on an object and ask, 'What holds up amid such free variations of an original [ ] as the invariant, the necessary, universal form, the essential form, without which something of that kind [ ] would be altogether inconceivable'' (Husserl 1977, sec. 9a). We will eventually come up against something that cannot be varied without destroying that object as an instance of its kind. The implicit claim here is that if it is inconceivable that an object of kind K might lack feature F,then F is a part of the essence of K. (stanford:phen)

free variation in imagination, n.All

free variation in imagination