Abstract
The modelling of ethical behaviour using some sources as described in modern philosophy is discussed. The model is phenomenalistic and very simple, using only elementary system concepts and needs further refinement, using the new results in neurobiology. The four sources of human behaviour used are: mind, emotions, tradition, and religion. The weighting of each is individually different and is time and environment dependent. Another phenominalistic model is that of a typical dictatorial system with two positive feedback loops. Some conclusions which are not rigorously proven but reasonable are derived. With these two examples it is shown that using only the simple concepts of system theory can help in getting a better insight into the behaviour of human systems.