Answer:
Philosophy.
Step-by-step explanation:
Philosophy is the basic theory about how a person lives. In other words, it can be described as the set of beliefs and theories that a person beliefs to be the basis of how he/she lives in a society.
The study of such beliefs and ideas of how a person lives his/ her life in society constitutes the philosophy of that person. These ideas and beliefs explain why a person acts in a certain manner or believes a certain thing and so on.