Which of the following concepts is a common part of most of the philosophical systems

To answer the question, we need to analyze the given options and identify the concept that is commonly found in most philosophical systems. Let's examine each option:

1. Dualism: Dualism is the belief that the mind and body are separate entities. While this concept is significant in certain philosophical systems, it is not universally present in all of them.

2. Empiricism: Empiricism is the theory that knowledge is derived from sensory experience. While empiricism is influential in certain philosophical systems, it is not a common element in all of them.

3. Rationalism: Rationalism is the belief that reason and logic are the primary sources of knowledge. Like empiricism, rationalism is a significant concept in certain philosophical systems but not universally present in all of them.

4. Ethics: Ethics is the branch of philosophy that deals with moral principles and values. Unlike the previous options, ethics is a concept that is commonly found in most philosophical systems. It is concerned with questions of right and wrong, good and evil, and how individuals should behave.

Based on the analysis, the concept of ethics is the most common part of most philosophical systems.