There are two main chemicals found in the plant that are used in medical cannabis â€“ Tetrahydrocannabinol (THC), which is the psychoactive element that produces the high, and Cannabidiol (CBD) which has no psychoactive effects. Medical cannabis has a higher CBD content so there is no THC-induced euphoria, which is what recreational users of cannabis are after.
Cannabis use for whatever reason is illegal in the UK, although recently licences have been issued for treatment of people with severe forms of epilepsy; medical cannabis can reduce the frequency and severity of seizures. There is also a plethora of anecodotal evidence that cannabis has successfully eased the symptoms of other conditions such as multiple sclerosis, Parkinsonâ€™s and cancer.
This raises a philosophical question that is crucially important when looking at public policy in areas such as drugs: when is it justifiable for the state to prohibit and punish particular sorts of behaviour?
It is wrong if someone is punished for a crime they did not commit. It is also wrong if someone is punished for an action that shouldnâ€™t be a crime in the first place, whether or not they are guilty of that crime. It would surely be wrong, then, to try to conduct a fair trial for an alleged crime unless it is fair and just that the alleged action is actually a crime.
For instance, it would be hard to justify giving someone a fair trial for, say, committing adultery or consuming a particular drug unless it is fair and just that it is a crime to commit adultery or take that drug.
He rejects the idea that public opinion can settle the matter. What he calls â€śthe tyranny of the majorityâ€ť is for him a subtle kind of oppression. He asks: what are â€śâ€¦ the nature and limits of the power which can be legitimately exercised by society over the individual?â€ť According to Mill: â€śThe only purpose for which power can be rightfully exercised over any member of a civilised community, against his will, is to prevent harm to others.â€ť He specifies that:
His own good, either physical or moral, is not a sufficient warrant. He cannot rightfully be compelled to do or forbear because it will be better for him to do so, because it will make him happier, because, in the opinion of others, to do so would be wise, or even right.
We may challenge people in such circumstances, according to Mill, and try to persuade them of the error of their ways. But as long as they are rational adults acting voluntarily, we should allow them to make their own mistakes. Only actions that harm other people should be crimes, according to Mill. That said, not all harmful actions should, in his view, be crimes.
Mill is aware that any of our actions might indirectly affect and possibly harm other people:
With regard to the â€¦ constructive injury which a person causes to society, by conduct which neither violates any specific duty to the publicâ€¦ or to any individual except himself, the inconvenience is one society can afford to bear for the sake of the greater good of human freedom.
One way of expressing the point is to say that there is a difference between harming people and harming them wrongfully. Not all harm that we suffer is an infringement of our moral rights.
For instance, it would be beside the point to claim that because such drug takers are likely to become ill and indirectly affect other people adversely through, say, their need for medical treatment by the NHS, it should be a criminal offence to consume cannabis.
As citizens, we do not have a moral duty to act in such ways that the policies devised by politicians remain affordable and feasible. Rather, politicians should devise policies that are affordable and feasible, given how people actually behave.
To punch someone on the nose is not only harmful it is wrongful. People have a moral duty not to punch us on the nose and we have a corresponding moral right not to be punched. However, we do not have a moral right to demand that others refrain from doing anything that might require medical treatment or any other sort of publicly financed services.
Much of our current legislation is not in accordance with Millâ€™s principle. We punish people for taking drugs that are harmful to them. The more harmful the drugs, the more severe our punishments. The punishments, particularly if they involve prison, are likely to be just as harmful (or even more harmful) as the drugs themselves. The cost of the imprisonment is likely to be more of a burden to society than the cost of prisonersâ€™ crimes. This all does seem very curious.
But objections might be made to Millâ€™s position. The prohibition regarding cannabis might possibly be morally justifiable on quite different grounds from those rejected by Mill. There might be a moral justification other than that suggested by Mill for making particular actions crimes.
For instance, what constitutes â€śharmâ€ť is debatable. Some might think that he does not convincingly suggest how we should distinguish between that which is wrongfully harmful and deserving of legal punishment, and that which is merely harmful. It might, for example, turn out that the activities of prominent and energetic Brexiteers or Remainers turn out to be far more harmful than those of, say, pickpockets and burglars. But it does not follow that such campaigners should be prosecuted as criminals.
Some actions such as, say, the defilement of corpses or voyeurism, where the people who are being watched remain unaware, might reasonably be crimes whether or not they cause harm. Perhaps not all crimes have victims.
Still, whether or not his argument is totally satisfactory, Millâ€™s â€śharm principleâ€ť offers a good starting point for a consideration of the crucially important but neglected question of the moral basis of the criminal law. And particularly when it comes to the issue of cannabis consumption.