This article proposes a conceptual model that interprets a human being as a unity of four hypostases: spiritual (Homo spiritualis), rational (Homo sapiens), passionate (Homo cupiditas), and animal (Hominidae). It is hypothesized that each of these hypostases has a dichotomous nature that manifests itself in polar modalities: positive, creative, and negative, destructive. This indicates the variability of human nature, i.e. the ability to change under the influence of various factors. The article reveals the criminological significance of this variability: it demonstrates its role in the genesis of criminal behavior and highlights the types of crimes committed when each of the aspects is chosen in a negative manner. At the same time, one or more of these aspects may: prevail, create various combinations among themselves, be in a congruent state or in dissonance, fragmentation, or chaos, and encourage or restrain behavior. In this way, they determine a person's modus vivendi and/or modus operandi. Methodology: the methodological basis of the study was formed by dialectical, systemic, comparative legal, and statistical methods. Conclusions: all four described hypostases and their opposing modalities are present in each person and, depending on their variability, shape their nature. Moreover, any one or more hypostases may: prevail, create various combinations with each other, exist in a congruent state or in dissonance, fragmentation, chaos, and stimulate or restrain behavior. They thus determine a person's modus vivendi ("way of life") and/or modus operandi ("mode of action").