The meeting of two personalities is like the contact of two chemical substances: if there is any reaction, both are transformed.

Jung’s simile frames human encounter as an alchemical process rather than a neutral exchange. Two “personalities” do not merely observe one another; they interact, and the interaction can catalyze change in both parties. The image of chemical contact suggests unpredictability (some mixtures are inert, others volatile) and mutuality (reaction alters each substance, not just one). In Jungian terms, such transformation can occur through projection, transference, and the confrontation with aspects of oneself mirrored in the other—especially in intimate relationships or therapeutic settings. The quote underscores Jung’s view that genuine relationship carries psychological risk and developmental potential: to meet another person deeply is to be changed.