Physiological typology endeavours first and foremost to ascertain the outward physical features by means of which individuals can be classified and their residual qualities examined. Kretschmer's researches have shown that the physiological peculiarities may determine the psychic conditions.
Jung distinguishes physiological (somatic) typology from psychological typology, granting that bodily features can determine psychic conditions while arguing that psychological typology works from inner principles rather than outward characteristics.
, The Structure and Dynamics of the Psyche, 1960thesis