Rosemarie Sand has resurrected the splendid theory of unconscious mental functioning proposed by G.W. Leibniz at the beginning of the eighteenth century, together with the contributions of Christian Wolff and other disciples during the following decades. The teaching of this Leibniz-Wolffian psychology was highly regarded and widely accepted during the nineteenth century. Freud himself relied on its conceptualization of unconscious mind during the decade before he created his own first theory. Its immediate, potential importance today is attributable to its being unencumbered by the controversial ‘Freudian’ features to which critics have objected, the grounds for the interminable ‘Freud wars.’ Devoid of these obstacles, the Leibnizian vision could easily serve as the common denominator for diverse Freudian schools; it could also render service as a common ground where psychoanalytic theoreticians and the experimenters of cognitive psychology could meet.

Adolf Grünbaum PhD, Andrew Mellon Professor of Philosophy, University of Pittsburgh

This is a brilliant book. Sigmund Freud’s seminal discussions of the unconscious mind are well known to the general educated public. Less well known are the contributions to the subject made by Freud’s predecessors. What Rosemarie Sand has done is to show in detail using previously untranslated German sources that in the eighteenth and nineteenth centuries, there were far more than hints, brief comments, and allusions to unconscious mentality. Beginning with Leibniz’s impressive contributions to psychology, there were well worked out theories and entire schools of thought devoted to the study of the unconscious culminating in the major works of the nineteenth century scholars Heinz Hartmann and Jonathan Herbart. In present day discussions of consciousness, most of the contributions of these pre-Freudian theorists of the unconscious tend to be ignored except by a few specialists. Psychologists, philosophers, and indeed anyone interested in the human mind can profit greatly from reading Sand’s The Unconscious without Freud.

Edward Erwin, PhD, University of Miami