Western Philosophers have expounded on every dimension — from the purely analytical to the metaphysical — in discourses on personhood. Conceptually, a person is defined by the characteristics of reasoning, consciousness, and persistent personal identity. The English philosopher John Locke defined a person as "a thinking intelligent Being, that has reason and reflection, and can consider itself as itself, the same thinking thing in different times and places; which it does only by that consciousness, which is inseparable from thinking, and as it seems to me essential to it" [4].
According to Boethius:
Person is an individual substance of rational nature. As individual it is material, since matter supplies the principle of individuation. The soul is not person, only the composite is. Man alone is among the material beings person, he alone having a rational nature. He is the highest of the material beings, endowed with particular dignity and rights.[citation needed] John Locke emphasized the idea of a living being that is conscious of itself as persisting over time (and hence able to have conscious preferences about its own future).
In a Lockean approach, some criteria a person might be required to have in order to be a person are one or more of the following:
Consciousness,
The ability to steer one's attention and action purposively,
Self-awareness, self-bonded to objectivities (existing independently of the subject's perception of it),
Self as longitudinal thematic identity, one's biographic identity.
Neo-Kantian philosophers over the last two decades have emphasized that conscious awareness requires both:
The sensorial capacity to access an environment (and one's own body) in a way that offers the basic qualitative content for subjective experience.
The intellectual capacity to conceptually interpret sensorial content as representing some thing to oneself.
Both of these capacities are required for a subject of experience, action, thought, or self-reflection to exist, at least in the physically embodied, world-accessing manner of humans (and presumably other intelligent animals). As Kant wrote:
Without sensibility no object would be given to us, and without understanding none would be thought. Thoughts without content are empty, intuitions without concepts are blind. [5].