Since Kant was never alive to actually discuss the theory of personhood, this entire answer is purely speculative, albeit the best possible answer given how the Categorical Imperative (CI) rendered his line of thinking.
First, let us discuss the two meta-theories surrounding the philosophical thinking behind personal identity, otherwise known as personhood. There is synchronic identity, which is a school of thought believes that an individual is said to be a person if said individual passes needed criterion simultaneously, at a given instance, and there is diachronic identity, that believes one is a person if one passes needed criterion at any instance. In simplest terms, synchronic identity is harder to achieve than diachronic identity.
In a certain set of dispositional theories, being fully-conscious is a requirement in being a person. However, when humans reach the deepest levels of sleep, studies have concluded that non-somatic portions of the brain comprehensively switch off. So, when we sleep, we are no longer persons under certain guidelines of synchronic personal identity.
Under the meta-theory of diachronic personal identity, as long as human passes that same aforementioned requirement, whether or not one is ever unconscious is irrelevant: if one was once a person, one will always be a person. That means those persons who are now dead are still persons, just at a later stage than us living persons.
Now, I keep bringing up dispositional theory of personal identity in regards to the two meta-theories of personal identity. Why, there are so many others? Well, Kant would likely have subscribed to a dispositional theory of personal identity as, being that he basically founded deontology, his ontological (of being/existing) perspective of personal identity would likely relate to a persons ability to make ethical choices. Making qualitative assessment on anything, especially something as simple as valuing something as either good, or bad, requires an enormous amount of reflection and inductive reasoning (if you are unsure what that is wiki has a really well-done article on it that is to understand). Now, it might be a stretch to subsume that Kant would believe that inductive reasoning is a requirement of making good intentions (again, he pretty much founded deontology), it would be pretty safe to say that dispositional theory, as it assess the quality of a person's ability to reflect on matters, would be where Kant would likely put greatest emphasis on, as inductive reasoning is really a proxy requirement of making value-judgements, which he believed as the most important part of decision-making.
This would imply that he probably would belong to the diachronic meta-philosophy for determining whether or not someone is in fact a person. If an individual was ever able to associate a good decision from a bad decision (basically, if someone was not in a consistant state of legal insanity), than said individual would be always be rendered as a person for Kant.
All that, it is important to remember what I wrote originally; it is impossible to know how Kant would have defined people as being persons or not. Kant never wrote about it, nor did he have access to all the philosophies we have had since the thinking of personal identity. Perhaps, by the time duty-based consequentialism was founded, he may have been a consequentialist. All of this pure supposition, and although I offered a lot of likely scenarios, having been spoiled with the plethora of theories of philosophies that do currently exist, it is infinitely hard to try and imagine how Kant would think with the limited set of philosophies existing in his time period.
Just curious, because I thoroughly enjoyed answering this question, was this for an assignment of any kind, or were you just curious?
Answers & Comments
Verified answer
Since Kant was never alive to actually discuss the theory of personhood, this entire answer is purely speculative, albeit the best possible answer given how the Categorical Imperative (CI) rendered his line of thinking.
First, let us discuss the two meta-theories surrounding the philosophical thinking behind personal identity, otherwise known as personhood. There is synchronic identity, which is a school of thought believes that an individual is said to be a person if said individual passes needed criterion simultaneously, at a given instance, and there is diachronic identity, that believes one is a person if one passes needed criterion at any instance. In simplest terms, synchronic identity is harder to achieve than diachronic identity.
In a certain set of dispositional theories, being fully-conscious is a requirement in being a person. However, when humans reach the deepest levels of sleep, studies have concluded that non-somatic portions of the brain comprehensively switch off. So, when we sleep, we are no longer persons under certain guidelines of synchronic personal identity.
Under the meta-theory of diachronic personal identity, as long as human passes that same aforementioned requirement, whether or not one is ever unconscious is irrelevant: if one was once a person, one will always be a person. That means those persons who are now dead are still persons, just at a later stage than us living persons.
Now, I keep bringing up dispositional theory of personal identity in regards to the two meta-theories of personal identity. Why, there are so many others? Well, Kant would likely have subscribed to a dispositional theory of personal identity as, being that he basically founded deontology, his ontological (of being/existing) perspective of personal identity would likely relate to a persons ability to make ethical choices. Making qualitative assessment on anything, especially something as simple as valuing something as either good, or bad, requires an enormous amount of reflection and inductive reasoning (if you are unsure what that is wiki has a really well-done article on it that is to understand). Now, it might be a stretch to subsume that Kant would believe that inductive reasoning is a requirement of making good intentions (again, he pretty much founded deontology), it would be pretty safe to say that dispositional theory, as it assess the quality of a person's ability to reflect on matters, would be where Kant would likely put greatest emphasis on, as inductive reasoning is really a proxy requirement of making value-judgements, which he believed as the most important part of decision-making.
This would imply that he probably would belong to the diachronic meta-philosophy for determining whether or not someone is in fact a person. If an individual was ever able to associate a good decision from a bad decision (basically, if someone was not in a consistant state of legal insanity), than said individual would be always be rendered as a person for Kant.
All that, it is important to remember what I wrote originally; it is impossible to know how Kant would have defined people as being persons or not. Kant never wrote about it, nor did he have access to all the philosophies we have had since the thinking of personal identity. Perhaps, by the time duty-based consequentialism was founded, he may have been a consequentialist. All of this pure supposition, and although I offered a lot of likely scenarios, having been spoiled with the plethora of theories of philosophies that do currently exist, it is infinitely hard to try and imagine how Kant would think with the limited set of philosophies existing in his time period.
Just curious, because I thoroughly enjoyed answering this question, was this for an assignment of any kind, or were you just curious?
Criteria For Personhood