“The foundation of [Rabbi Schneur Zalman’s] psychological system is based on the doctrine of the ‘two souls’… conceived as the sources of all human activity, and of the conscious and unconscious forces behind them.

…

The so-called ‘animal soul’ (nefesh ha-bahamit)…is the vital principle that animates the physical body, the ‘life’ of the body… It is the source of the bodily instincts and appetites…

But in addition to its animal functions, the vital soul in man possesses certain essential qualities, such as intellectual and emotional attributes, which are not to be found in the lower animal species…

These… include… many dispositions, both good and bad, which are ‘natural’ to most men, and which come under what is commonly called ‘human nature.'”