Law
Law is a system of rules that are created and enforced through social or governmental institutions to regulate behavior. Law is a system that regulates and ensures that individuals or a community adhere to the will of the state. State-enforced laws can be made by a collective legislature or by a single legislator, resulting in statutes, by the executive through decrees and regulations, or established by judges through precedent, normally in common law jurisdictions. Private individuals can create legally binding contracts, including arbitration agreements that may elect to accept alternative arbitration to the normal court process. The formation of laws themselves may be influenced by a constitution, written or tacit, and the rights encoded therein. The law shapes politics, economics, history and society in various ways and serves as a mediator of relations between people.
Psychology
Psychology is the science of behavior and mind, including conscious and unconscious phenomena, as well as feeling and thought. It is an academic discipline of immense scope and diverse interests that, when taken together, seek an understanding of the emergent properties of brains, and all the variety of epiphenomena they manifest. As a social science it aims to understand individuals and groups by establishing general principles and researching specific cases.
Law
We must not, by any whimsical conceits supposed to be adapted to the altering fashions of the times, overturn the established law of the land: it descended to us as a sacred charge, and it is our duty to preserve it.
Lord Kenyon, C.J., Clayton v. Adams (1796), 6 T. R. 605.
Psychology
Unlike the physicist, the psychologist … investigates processes that belong to the same order — perception, learning, thinking — as those by which he conducts his investigation.
Morris R. Cohen, Reason and Nature (1953), p. 81