When a person isn’t of a sound mind, they are still expected to maintain their responsibility but they may simply be unwell. Unable to be responsible for themselves or their actions.
We have various ways of dealing with this. Contracts are not enforceable (or can be deemed unenforceable) against people who were not of sound mind when entering into them, meaning if you are contracting with someone, you have an incentive to make sure they are of sound mind at the time. There are a bunch of bars you have to clear in terms of mental capacity and non-coercion and in some cases having obtained independent legal advice, in order to be able to enter into a valid contract, depending on the context. As well, if someone is unwell but self-aware enough to know something is wrong, they have the option of granting someone else power of attorney, if they can demonstrate enough capacity to make that decision. If someone is unwell but not aware of the extent of their incapacity, it is possible for a relative to obtain power of attorney or guardianship. If a medical professional deems someone not to have capacity but there is no one able or willing to take on decision making authority for that person, many polities have something equivalent to a Public Trustee which is a government agency empowered to manage affairs on their behalf. If you show up in hospital and you are not well enough to communicate your preferences and/or a medical professional believes you are not of sound mind, they may make medical decisions based on what they believe to be in your best interest.
These may not be perfect solutions (far from it) but “you’re drunk” or “you’re a minor” are not the only times when society understands that people may not have capacity to make their own decisions, and puts in place measures to get good decisions made on behalf of those who lack capacity.
Of course (and possibly, correctly) many of these measures require clear demonstration of a fairly extreme/severe lack of capacity, before they can be used, so there’s a gap for those who are adult in age but childish in outlook.
We have various ways of dealing with this. Contracts are not enforceable (or can be deemed unenforceable) against people who were not of sound mind when entering into them, meaning if you are contracting with someone, you have an incentive to make sure they are of sound mind at the time. There are a bunch of bars you have to clear in terms of mental capacity and non-coercion and in some cases having obtained independent legal advice, in order to be able to enter into a valid contract, depending on the context. As well, if someone is unwell but self-aware enough to know something is wrong, they have the option of granting someone else power of attorney, if they can demonstrate enough capacity to make that decision. If someone is unwell but not aware of the extent of their incapacity, it is possible for a relative to obtain power of attorney or guardianship. If a medical professional deems someone not to have capacity but there is no one able or willing to take on decision making authority for that person, many polities have something equivalent to a Public Trustee which is a government agency empowered to manage affairs on their behalf. If you show up in hospital and you are not well enough to communicate your preferences and/or a medical professional believes you are not of sound mind, they may make medical decisions based on what they believe to be in your best interest.
These may not be perfect solutions (far from it) but “you’re drunk” or “you’re a minor” are not the only times when society understands that people may not have capacity to make their own decisions, and puts in place measures to get good decisions made on behalf of those who lack capacity.
Of course (and possibly, correctly) many of these measures require clear demonstration of a fairly extreme/severe lack of capacity, before they can be used, so there’s a gap for those who are adult in age but childish in outlook.