Yekke2:
Perhaps I should have made myself clearer. To my mind, the difference between being a child and an adult in legal terms is personal responsibility. The legal definition of adulthood should be the age at which the individual is in all respects deemed old enough to take full responsibility for their actions. This would extend to anything. For me, it is a fundamental dichotomy for the state to impose further age restrictions on people who have already reached adulthood. It isn’t just a label, it’s a legal concept. I’m not necessarily saying this is the case, only that it should be.
Now, in my opinion the role of the legal system is govern the boundaries where people’s actions have consequences on others around them. If this sounds simplistic or obvious, all governments overstep their mark by imposing restrictions that it is not within the essential remit of a democratic liberal system. So therefore, even from a libertarian standpoint, taking heroin or driving drunk would be illegal, as you’re placing others at risk, not just yourself. So too would does it make sense to require a certification to drive, as otherwise you’re placing others at risk. On occasion, there is a common sense case to be made for banning things that are harmful to society as a whole, such as possessing guns, even though a hardcore libertarian would feel this is outside the remit of governance. But all of these things are equally applied across society. Telling adults of a particular age that they are not permitted to drink, whilst allowing others, is unequal. A supposed scientific basis is not enough, there needs to be an ethical and legal case.
Drinking alcohol is a matter of responsibility. And it is wrong to tell somebody otherwise deemed fully responsible for themselves and their actions by the state, that they are not responsible enough in this narrow regard. If they feel 19 year olds truly aren’t responsible, and bring evidence from increased drink driving rates or the like, then they should be legally considered children, with commensurate voting and tax legislation.
I justify monitoring and restricting children thus: The state is responsible for the welfare and actions of children, hence legal guardianship, and juvenile courts. They are not deemed legally equipped to take responsibility for themselves, so the state does it for them. So having different stages at which children are permitted to take responsibility for certain behaviours, such as driving, is sensible. There is a fundamental difference between a 17 year old and a 7 year old, in that a 17 year old can generally be adjudged capable enough to drive. Both are children, and are unequipped to decide for themselves, so the state decides for them. But adults should all be equal under the law, in terms of responsibility and capability. So do deem some adults less capable than others on account of their age seems nonsensical. I would object to requiring 100 year olds to hand in their driving licenses, although they should have to prove they are capable of driving safely. That’s the key distinction. If something is deemed unsafe for a 20 year old, it should be similarly restricted for 40 year olds. Either that or change the arbitrary cutoff age at which one is deemed mature.