Law is essentially a social phenomenon, and therefore is in full association with other social sciences. A legal rule must be interpreted to be understood, and for interpretation, we will also have to argue therefore, the relationship between reasoning, interpretation and law is unbreakable. Besides this, the three categories of base, source and purpose of the legal rule are considered as the contributors to each legal system. Which are as a problem, is that if we are to seek social justice and fairness in law, why it takes shape different arguments, sometimes conflicting, in the same subjects? Will this not damage the realization of the order as one of the goals of the legal system? This phenomenon is explained as pluralism of legal argument, which is shaped by various factors, most notably ideology. The mutual relation between law and ideology in legal pluralism is controversial. Depending on what the ideology governing the mind of a legal practitioner is, his kind of argument in the interpretation of the legal rules will be equally different, which will be discussed in detail in this study.