The individual, for Edith Stein, is a psycho-physical individual. It is composed of the psychic, which is the unifying principle, making the individual a separate being. And it is also composed of the physical. In the individual, both are intrinsically tied to each other. Stein says, “[T]he soul is always necessarily a soul in a body (p. 41).”

The first part of the series tackled the givenness of the living body. The second part tackled the living body and feelings. This post will tackle the Soul and Living Body, Psycho-Physical Causality.
Soul and Living Body, Psycho-Physical Causality
First off, Edith Stein reiterates that the “soul together with the living body forms the ‘psycho-physical’ individual (p. 50).” Because of this inherent connection between the two, she would say that “everything psychic is body-bound consciousness (p.49).” This simply means that anything that relates to the psychic happens within the limits of the body, for the individual is necessarily a psycho-physical individual.
Stein, then, explores the idea about spiritual feelings, another type of feeling in addition to the other types of feelings. According to Stein, spiritual feelings in their purity are “accidentally psychic and not body-bound (p. 50).” She brings an argument that states that feelings cannot be phenomenally separated from the physical, believing that all feelings are body-bound. As a counter-argument, however, she would say that spiritual feelings are separate despite that they may be accompanied by physical changes as part of psycho-physical causality. She says, “When we think the living body away, these phenomena disappear, though the spiritual act remains (p.50).” When one is frightened, for example, there would be a rush of adrenaline in the body, which would result in one’s alertness. But this does not mean that adrenaline rush is part of being frightened. Rather, the spiritual feeling of fright caused the adrenaline rush. Spiritual feelings may be found in the psycho-physical bounds, but they essentially operate in a non-somatic way.
Stein proceeds that physical experiences have a causal influence on the psychic or the soul. She would explain this with human capacities being strengthened by training or weakened by inaction (p. 51). One example she gives is when someone works on natural science, his or her “power of observation” develops. Another example of this is when a person practices his or her singing talent. But when a person stops practicing, the capacity weakens. Stein, then, contends that physical events affect the soul.
Stein, however, gives sophistication by also mentioning that there will come a time in developing the capacities that the opposite effect happens. She calls this a consequence of “habituation,” that is, when a practice becomes a habit. And when this happens, boredom or other feeling strikes, which makes the person disinterested. So instead of an increase, the training might just weaken the capacity. Stein concludes, then, that “the physical is phenomenally having an effect on the psychic (p.51).”
*All of the above is based on Edith Stein’s On the Problem of Empathy.