The legal subject is the representation of an entity, human or non-human, that is recognised under law as a holder of rights and duties. Most legal subjects can also exercise legal powers, with or without the help of a legal representative.
Different legal subjects can transact with one another on level terms. This means for example that an individual natural person is empowered to purchase a car from a multi-national corporate legal person, with the legal effect of the contract binding both sides despite their difference in nature and size.
The abstract uniformity of the legal subject allows the latter to assert rights and powers under the rule of law, no matter the particular characteristics of the underlying entity it represents. This means that in principle all are given equal opportunity to argue for a legally effective remedy.
Only a legal subject can perform juridical acts, such as entering into a contract; other ‘things’ might have relevance for the law, such as cars, mountains, or money, but these ‘legal objects’ are what is transacted with by legal subjects.
Not all legal subjects can act in the same ways – they have different sets of subjective rights and legal powers. For example, a minor or someone with serious cognitive impairments (both natural persons) will be unable lawfully to enter into certain kinds of contract, such as marriage, or to engage in certain acts, such as driving.
Who and what is given legal subjectivity is determined by positive law. Since the horrors of World War II, however, all humans have been given legal subjectivity by default, in order to provide a minimum threshold of legal protection.
The range of possible legal persons varies between jurisdictions. The classification of a multi-national car manufacturer as a legal person, for example, is the result of a process of incorporation. This means the requirements and process for creating a company defined by the positive law of a particular jurisdiction have been met and followed, with the legal effect of creating a new legal person with legal subjectivity.
Only positive law can bestow legal subjectivity: an autonomous car, a rock, or a cat cannot have legal subjectivity unless and until the positive law says otherwise. It follows that legal subjectivity is not a given, but a choice reflected in positive law.