Hugo Grotius was a towering figure in philosophy, political theory, law and associated fields during the 17^th century and for hundreds of years afterwards. His work ranged over a wide array of topics, though he is best known to philosophers today for his contributions to the natural law theories of normativity.

Aquinas recognises four main types of law: The eternal, the natural, the human and the divine. The last three all depend on the first, but in different ways. Were we to arrange them in a hierarchy, eternal would be at the top, then natural and then human. Divine law is not in conflict with natural law, but it reaches human beings by a different route, revelation.

That is the view of Gray in his "Nature and Sources of the Law". He said that the law is what the judges declare; that statutes, precedents, the opinions of learned experts, customs and morality are the sources of the law.

Law is the body of rules and principles governing the affairs of a community and enforced by a political authority.

Duguit-Living law According to Duguit, the basis of law is the objective fact of 'social solidarity'. 

Per incuriam, literally translated as "through lack of care", refers to a judgment of a court, which has been decided without reference to a statutory provision or earlier judgment which would have been relevant.

The term 'legislation' is derived from two Latin words, ‘legis’ meaning 'law' and ‘latum’ meaning 'to make, put or set'. Etymologically, 'legislation' means 'the making or the setting of law'.

Ratio decidendi is a principle, namely the general reasons given for the decision or the general grounds upon which it is based, detached or abstracted from the specific peculiarities of the particular case which gives rise to the decision.

The following are the essential elements of a custom:

1. Antiquity
2. Continuance
3. Peaceable enjoyment
4. Matter of right
5. Certainty
6. Consistency
7. Conformity with statute law

Law can be an instrument of social change. Introduction law is an important mechanism for regulating society. It also brings about amazing social change. Social change means there is must change in social structure. Social structure can be understood as nature, social behaviour, social relations, social organisations or community of people.

According to realists, the law is what the judges decide.

The ownership is the de jure recognition of the right over the property. The possession has limited rights to consume, destroy and alienate. Thus, full enjoyment of the property is restricted in possession and there is no restriction in ownership.

Natural law is a philosophy that certain rights or values are inherent by virtue of human nature and universally cognisable through human reason.

In Jurisprudence, ‘Bracket theory’ is related with legal personality. According to Ihering, the conception of corporate personality is essential and merely an economic device by which we can simplify the task of coordinating legal relations.

Ihering elaborated the relation of law to social change. Even more influential in the 20^th century was his law as a means to an end, which maintained that the purpose of law was the protection of individual and societal interests by coordinating them and thus minimising occasions for conflict.