There is no exact and agreed concept or definition of ‘person’ in either common usage or philosophy. Instead the word ‘person’ has numerous uses. The English word is said to come from the Latin persona. This word was used to refer to the mask worn by actors in dramatic performances and also variously to the person speaking through the mask. It has been suggested in turn that persona is in itself derived from per-sonando (‘sounding through’). This murky beginning may account in part for our current ambiguous usage.

With this in mind, when we discuss the question of ‘personhood’ we are in fact attempting to give a more or less vague term a degree of precision by locating it within a set of terms which constitute the vocabulary of a scientific or philosophical theory. It is therefore misleading to speak of a particular philosopher’s theory of persons for there is no previously agreed definition of what this should a theory of. We must instead talk of the philosopher’s use of ‘person’ as a semi-technical term in his or her system. There must be some connection between this philosophical term and the ordinary concept otherwise there would be no justification for using this term rather than any other; but we cannot criticize a philosophical use of the term by citing certain facts about persons that the theory in which it is used fails to account or accounts for incorrectly. We may criticize it only by showing that its rules of usage are incoherent or that there is nothing in the world that satisfies the characterisation of ‘person’ as given by the theory.

Philosophers have mainly concerned themselves with two issues regarding personhood.

• What qualities must a ‘person’ possess?
• Are ‘persons’ essentially physical or mental entities?

With regards to the first question Boethius regarded rationality has been an important quality. Writing in the sixth century he said:

[a person is] an individual substance of a rational kind (naturae rationalis individua substania)

This rationality approach was echoed by Locke who said that the term ‘person’ should be applied:

Only to intelligent agents capable of a law and happiness and misery (An Essay concerning Human Understanding, Book II Chapter 27)

And that a person is a:

Thinking, intelligent being, that has reason and reflection, and can consider itself as itself (Ibid.)

In his Introduction to the Metaphysics of Morals Kant made a similar point:

A Person is the subject whose actions are capable of imputation

Kant wished to make a distinction between ‘persons’ and ‘things’. He felt that ‘persons’ as contrasted with ‘things’ are of an
unconditional worth and that ‘respect’ is an attitude which has an application to ‘persons’ only and never to ‘things’. In view of this, ‘things’ may be pre-empted for our own purposes; their value depending upon the degree and kind of service that they may be to us in the execution of our aims. Persons may not be used in this way. They are ‘ends-in-themselves and sources of value in their own right’ (Kant)

By this view a person simply is any being having legal rights and duties. But not every human being is legally a person and not every legal person is a human being (a corporation is considered to be a judicial person). A slave by definition is used as a means to another’s ends. In ancient legal tradition slaves had no rights in the eyes of the law and were therefore not regarded as persons. Aristotle regarded them not as human beings, but as ‘[living]instruments for the conduct of life’. In Aristotle’s vew to be a ‘person’ such an entity must take part in the community of which he or she is a member. However, as in the case of slaves, not everyone who might be a member of the community is recognized as being fit to play a role in its public life. So, in the view of Aristotle, a ‘person’ is required to meet certain criteria of enfranchisement; satisfaction of these criteria constitutes someone a person or citizen.

Finally commonly a necessary condition for having rights is being responsible for one’s acts. Rights may be ascribable only to persons and accordingly persons alone are responsible.

With respect to the mental/physical debate Locke and Strawson have made major contributions: Locke wrote again in An Essay Concerning Human Understanding:

In the ordinary way of speaking, the same person and the same man stand for one and the same thing.

Yet Locke himself believed that these two expressions stand for two distinct ideas: ‘person’ having to do with the rational self, and ‘man’ having to do with a certain physical shape. A rational parrot, he argued, would not be called a man, nor would a non-rational human being be called anything but a man. The former however might be a person, while the latter, failing in rationality, might not be. A person then is not a rational man since ‘man’ has reference to corporeal form and
it is not, as he saw it, part of the meaning of ‘person’. Then Locke inferred that ‘person’ must denote something incorporeal and invisible. This deviates from common usage as a standard dictionary definition states ‘person’ means ‘the bodily form of a human being’. For Locke the identity of a person was simply the identity of consciousness, so that I remain the same person if I am conscious of being so even though my body could drastically change or indeed cease to exist at all.

For Locke persons were essentially non-corporeal simple entities. A difficulty with this is that it becomes difficult to distinguish persons from metaphysical selves. If we follow their reasoning in ascribing rights and responsibilities to human beings we are implicitly referring to some bodiless entity.

P. F. Strawson adopted a term for ‘person’ for philosophical use which is much closer to the common usage. A Strawsonian person is understood as distinct from a material body. For Strawson, a thing, or material body is a basic particular specifically in the sense that a physical body can be identified without reference to any other particular than its physical existence. He states that we are not our physical bodies, but does not follow the Lockian path that we are then immaterial entities.

Strawson chooses to introduce two terms: M-predicates and P-predicates, applicable respectively to material bodies and to persons. There is an overlap in that some M-predicates are applicable to persons, but there are some P-predicates that we would not be able to apply to material bodies (for example, states of consciousness). Persons therefore are distinct from material bodies but they are not therefore immaterial bodies or incorporeal nonbodies. A person has states of consciousness as well as physical attributes and is not merely to be identified with one or another.

Strawson’s concept is close to the whole concept of a person in ordinary usage. However, relative to the known laws of physics and chemistry, persons are indeed primitive and irreducible entities. A person is a body; is an appearance, is self conscious and rational; is the source and object of rights and obligations; is that which takes roles and discharges functions. In this sense then the dual nature of a person resembles the quantum mechanical particle neither a being a particle nor a wave but rather different things depending on how one might choose to observe it.

The Encyclopedia of Philosophy Volume 6 pg112-113; Paul Edwards
Editor: Collier-Macmillan Ltd London 1967.
A Dictionary of Philosophy Pan Books Antony Flew Editor 1979

Wikipedia
The Internet Encyclopedia of Philosophy

Quite literally the term ‘philosophy’ derives from the Greek philosophos means ‘love of knowledge’. Defined broadly, philosophy is an activity people undertake when they seek to understand fundamental truths about themselves, the world in which they live and their relationships to the world and to each other.

This is only one definition and there are many others, as even philosophers between themselves cannot agree on what philosophy is: a search for the wisdom of life; an attempt to understand the universe as a whole; an examination of human kind’s moral responsibilities and social obligations; an effort to fathom the divine intentions and our place with reference to them; an effort to ground the enterprise of natural science; a rigorous examination of the origin, extent, and validity of people’s ideas; an exploration of the place of will or consciousness in the universe; an examination of the values of truth, goodness, and beauty; an effort to codify the rules of human thought in order to promote rationality and the extension of clear thinking, or simply engaging in asking, answering, and arguing to gain answers to life’s most basic questions. And even these do not exhaust the meanings that have been attached to the philosophical enterprise, but give some idea of its extreme complexity and multi-facetedness.

What this confusion does illustrate is a pertinent issue relating to philosophy, namely that it aims to leave nothing unquestioned, even the nature of its very existence. It is difficult to determine whether any common element can be found and whether any core meaning can be discovered that could serve as a universal and all-inclusive definition. Vague and indefinite as the above interpretations are, they do suggest two important facts about philosophizing: that it is a reflective, activity and that it has no explicitly designated subject matter of its own but is a method or type of mental operation that can take any area or subject matter or type of experience as its object. Thus, although there are a few single-term divisions of philosophy such as logic, ethics, epistemology (the theory of knowledge), or metaphysics (theory of the nature of Being) its divisions are often best expressed by phrases that contain the word ‘of’. Thus we have philosophy of nature, philosophy of mind, philosophy of law, and philosophy of art.

Philosophy’s goal is broad: whereas other fields study particular kinds of things, philosophy asks how they all fit together. For example biological sciences study the body, and psychologists study the mind, but in order to discuss how the mind relates to the body we need philosophy. Furthermore philosophy also ponders whether we can consider any belief we hold to be ‘knowledge’ and whether it is possible to have any ‘knowledge’ at all. Such arguments are very abstract, but this is what enables philosophy to cover so many difference fields at once.

On a more practical level, unlike other disciplines, in order to study philosophy you also need to do it. For instance to study poetry you do not need to be a poet, yet to study philosophy you have to engage in philosophical argument, not perhaps reaching the level of great thinkers of the past, but developing some of the same skills as them. Whilst doing this, it is not simply enough to express one’s views but one must try to convince others. It is also of note that the history of philosophy has a living significance, which the history of science does not enjoy. In science, the present confronts the past as truth confronts error; thus, for science, the past is important only out of historical interest. In philosophy it is different. Philosophical systems are never definitively proved false; they are simply discarded or put aside for future use. And this means that the history of philosophy consists not simply of dead museum pieces but of ever-living classic works comprising a permanent repository of ideas, doctrines, and arguments and a continuing source of philosophical inspiration to those in any succeeding age. It is for this reason that any attempt to separate philosophizing from the history of philosophy an unnecessary impoverishment of its rich natural resources.

Finally, why is philosophy important? Some people choose to characterise philosophy as something with no relevance to modern life; they think it a subject to be studied from an armchair purely for intellectual satisfaction. Intellectual satisfaction is no small justification in itself but this is nevertheless a serious misrepresentation of the subject. Many debates that we have as a part of society have, as their basis, underlying assumptions amenable to philosophical enquiry. Every domain of human experience raises questions to which its techniques and theories apply, and its methods may be used in the study of any subject or the pursuit of any vocation. Philosophy is in a sense inescapable: life confronts every thoughtful person with some philosophical questions, and nearly everyone is guided by philosophical assumptions, even if unconsciously.