The bioecological model developed by Urie Bronfenbrenner includes the process, person, context, time framework and a concept of interaction known as proximal process. While the concept of proximal process is essential in explaining developmental outcomes, it has not been fully developed. The goal of this inquiry is to focus in particular on proximal process and examine some aspects of it in terms of the Aristotelian four causes. Bronfenbrenner’s theory is introduced, and proximal process is defined and briefly appraised. The four Aristotelian causes are defined, and examples are suggested. The concept of proximal process is examined with regard to material cause, formal cause, efficient cause, and final cause. It is important from the perspective of developmental research to more fully define proximal processes and to conceptualize them in terms of the four causes that were described by Aristotle. Such a conceptualization could lead to identification of measurable variables that represent the four Aristotelian causes.