Identity

We explain what identity theory is and which philosophers studied it. Also, what are the ontological and logical principles of identity.

What is identity?

Identity is a philosophical concept that It is used to mark the relationship of belonging or equality of a thing with itself. In the case of philosophy, by saying that every thing that can be equal to itself is identical to itself, by “thing” we must understand both subjects and objects as they are “in themselves.”

As with the concept of contradiction, The concept of identity can be examined from various points of view. In general, it is used to formulate different principles. From an ontological or metaphysical point of view, the concept of identity is used to set the ontological principle of identity. From a logical point of view, however, it is used to set the logical principle of identity.

Both the ontological principle of identity like him logical principle of identity They seem to have their origin in the theory of identity that emerged in the Greek world. This is related to the idea of ​​the permanence of a subject that is always itself, as well as a search for one's own interiority (an identity whose foundation, for its part, can be traced to logical and ontological principles). For this reason, it is often difficult to establish what came first, whether the ontological and logical principles or the theory of identity.

Beyond these principles, in general one can speak of identity, as Aristotle points out, in several senses: real identity, rational or formal identity, numerical identity, specific identity, generic, intrinsic or extrinsic identity, causal identity, primary or secondary identity , etc. However, it can be seen that All of them end up being reduced to two forms of identity: logical or formal identity and ontological or real identity..

Etymology of the term “identity”

The term “identity” was expressed in classical Greek through the adjective car (αὐτό), which means “same” or “the same,” and the pronoun to auto (το αυτό), which translates as “this one”. Both are equivalent, in Latin, to ipse“himself”, or idem“this”. In all these cases, The demonstrative is used to indicate that a subject or an object are the same.

In this way, it is indicated that an object or a subject:

• It is the one who is there and is remembered in the same way as in his previous presence.
• It is in itself, being by itself or cause of itself, as Plato indicates when he says that “man in itself or by itself” exists as an idea, its own being, always equal and non-changing.

This etymological conception, of Platonic origin, uses “authenticity” as a form of identity to indicate that the identity of something is given by the same entity as it is itself the one that gives itself its authenticity and its essence, without its essence changing. as it does with sensitive and temporal things.

Regarding its Latin etymology, identity as ipse either idem appears as an adjective or demonstrative pronoun that insists on indicating that something is a precise thing and differentiated from another thing. “Identity” is assumed to be a late Latin form of identitas“the same entity”: ditto.

Identity theory

Identity theory is used to refer to subjects and objects that are “in themselves.”. Talking about the identity of the subject means that the subject, as subjicere (“lay” or “put under”), is what remains below, beyond its accidents (which are those attributes that can change), and furthermore, always remains the same.

The latter implies that what was before is what it is now and what it will be after, beyond its accidental attributes. That there is “authenticity,” as Plato maintains, or identity or “authenticity,” means that a subject is and is permanently in its substance or essence.

These first Greek indications of identity, given in the sphere of everyday life, took their idea from the legal order in relation to cause. Identity is born from the fact of being responsible and, therefore, must be responsible for what is done and what is said.

This means admitting that the subject is permanenthe is always himself and, furthermore, is cause of the action for which he is judged and for which he must answer. If the subject were not the same and, for example, the defendant in a trial was not the same as yesterday, he could not be held responsible for the acts committed and condemned in the legal order.

The act of responding for an event of which one is the cause originates in the logical principle of identityas formulated by Parmenides and later reaffirmed by Aristotle: “what is, is.” This means that being must be thought of as being the same throughout time without being the opposite (from which the principle of non-contradiction follows).

In this way, identity, as a personal or objectual identity, is founded on the identity of the being, even though in the Greek world the idea of ​​“personal” identity had not yet appeared.

Identity principles

Identity as a philosophical concept can be thought of from different and varied points of view. However, the two most used and discussed are the ontological point of view and the logical point of view. From them emerge the ontological principle of identity and the logical principle of identity.

• ontological principle of identity. It states that every thing is equal to itself, in Latin: ens es ens.
• Logical principle of identity. It states that for every entity x, x is equal to itself.

The separation of one principle and another is not simple. In general, the history of philosophy has mixed and even confused both meanings. Some authors maintain that the foundation of the logical principle of identity is in the ontological principle or that both are two aspects of the same conception that maintains that the real is the identical, since the concrete, like an object, can be distinguished from “another.” concrete: it is not the same this tree that that.

ontological principle of identity

The ontological principle of identity says that everything is equal to itself. In Latin this is written ens es ens. Some authors maintain that this occurs when applying the logical principle to time. To say that an object is identical to itself is not to assert that a proposition is identical to itself, but rather it is a statement concerning the nature of a real object. Thus, that a thing be equal to itself in time implies that all the time stay as herself.

For Kant, the question of identity is a transcendental postulate of reason. In the Critique of pure reason, Kant maintains that identity is the activity of a subject that allows different representations to be identified as manifesting themselves.as being given, to a unit that is always the same (an idea similar to the notion of an “I”).

Schelling and Hegel also continued similar ideas. Even Heidegger held an idea of ​​identity by which he determined that it refers to an entity considered equal to itself, which presents unity with itself.

Logical principle of identity

The logical principle of identity says that for every entity x, x is equal to itself. This is presented as a logical tautology that states “if pso p”; and also: “p yes and only if p”. Both statements contain a constant (“if…then…” and “…if and only if…”) and a propositional variable “p”.

The logic of identity is based not on propositional terms but on equivalences of belonging. For example, instead of saying “if the moon, then the moon,” where the term “moon” is replacing the propositional variable p and refers to a self-identification, the logic of identity can say “the moon is the satellite of the Earth”, establishing an identification or equivalence between “the moon” and being “the satellite of the Earth”.

This occurs because the logic of identity operates with different laws, such as the law of substitutivity of identity (which states that two entities are identical if what is stated about one is true of the other) and the law of transitivity (which states that if two entities are equal to a third, they are equal to each other).

Principle of identity of indiscernibles

A particular case of the principles of identity is that formulated by the German philosopher Gottfried Wilhelm Leibniz (1646-1716), the principle of identity of indiscernibles. Also known as Leibniz's law, the principle of indiscernibles is one of the great metaphysical postulates of the German philosopher.

Broadly speaking, this principle consists of deny that two things can have the same characteristics and at the same time be numerically different. Thus, two things absolutely equal and indiscernible They are identical and they are the same thing.

The foundation of the principle of indiscernibles is given in the following ontological principles:

• If two objects share all their properties, then they are identical and therefore the same object.
• If two objects share all their qualitative properties, then they are identical.
• If two objects share all their non-relational qualitative properties, then they are identical.

References

• Astacio, M. (2001). Identity in the metaphysical essence. A Parte Rei Magazine.
• Rivano, J. (1957). On the principle of identity. Philosophy Magazine, 4(1), 34-48.
• Renero, A. (2007). Identity and understanding: Schelling or an intermediate instance between Kant and Hegel. En-keys of thought, 1(2), 23-45.
• Augusto Míguez, R. (2009). Schelling's philosophy of identity: the Absolute as perfect unity.
• Del Rosal, F.I. (2014). Hegel and identity as a process. Eikasia Philosophy Magazine, 58(58).
• Heidegger, M. (1988). Identity and difference (Vol. 16). Anthropos Editorial.
• Fernández Pereiro, A. (1966). The triple identity of Being, Thinking and Doing in Plato.