Consider the A&E doctor's dilemma. Someone suffering from severe depression is brought to hospital, having made a serious suicide attempt. Without treatment, they will die. But they insist they want only palliative care and will regard any attempt to prevent their death as assault.
There's not much time to make a decision. And there are two conflicting pieces of legislation to confuse the issue. The Mental Health Act says intervention is required where a mentally-ill individual is a danger to themselves (or to the public). But the Mental Capacity Act (2007) is organised around a very different legal principle: it says that if someone passes a legal test of their capacity to make a decision, then they cannot be treated without their consent – even if they suffer from a major mental disorder.
This is not a theoretical scenario – it happens. So do various others involving mental-health conditions – anorexia is one, schizophrenia another – that potentially have life or death consequences.
Philosophers are now being asked to help medical and social care professionals to think through the collisions between these different approaches.
This has been prompted because a range of factors are making the need for careful thinking around the issue of autonomy more pressing: the neuroscience that helps us to understand the way decision-making processes happen in the brain is advancing rapidly. Psychiatry as a clinical discipline now operates in a legal environment increasingly shaped by human rights legislation. And decisions regarding the treatment of the mentally ill are regularly contested in the courts.
"Our aim is to develop a conception of autonomy that is philosophically defensible and can be applied in practice," explains Essex University's philosophy professor, Wayne Martin, now leading the Essex Autonomy project, funded by the Arts and Humanities Research Council.
"My initial involvement came about when I was approached by psychiatrists at the Maudsley Institute of Psychiatry who were working on the assessment of mental capacity in the lead-up to the Mental Capacity Act taking effect. They wanted to figure out what it is like for the person actually making a decision. But they also needed a methodology for answering that kind of question.
"The Mental Health Act essentially says 'We want to protect the public from mad people'," he explains.
"That test is a public safety test; if you're a danger to yourself or to others, then the state has a responsibility to minimise the threat to public health. In the old days, that probably meant locking you up; now, it could mean that you are forced to take your medication. Safeguards have been introduced. But the key thing is that there is nothing in that Act that talks about your freedom to make decisions for yourself. It's all about 'are you a danger?'"
The Mental Capacity Act, by contrast, codifies ideals that have gradually been emerging in case law, he explains. "These ideals invoke the very grand principle that a person has the absolute right to refuse medical treatment as long as they have the mental capacity to make that decision. So then the question is, how do you decide whether they have that capacity?"
The legal test for mental capacity – that you understand information, have the capacity to use and weigh it, and that you can express your choice – is problematic as it stands, he says, but no matter how much it's refined, there will still be difficulties.
"Professionally speaking, anorexia patients are fascinating in how they demonstrate this," he says. "They pass the standard capacity tests with flying colours, they often have real insight into their condition, and yet they make terrible decisions. Interestingly, later on, when they are somewhat recovered, some say that though they had been expressing themselves clearly and passed the test, inside they were crying out for the very treatment they were adamantly refusing."
Martin has just returned from the first of a series of weekend workshops that will bring together interested colleagues from the worlds of psychiatry, law, social welfare and philosophy. One of the biggest difficulties will be working beyond the usual disciplinary boundaries.
"A big challenge is getting people to talk across their disciplines," says Martin.
But it is important to get people to question their assumptions. "We think it is obvious that autonomy is worth pursuing. But the word 'autonomy' means self-legislation. Historically, it's actually a very controversial concept that hasn't always been held up as the ideal. We need to think about whether and why autonomy is the right ideal for beings like us."
Linked to that is a problem regularly encountered in observing decision-making by people with a mental-health condition – the role played by time. Nowadays, Martin says, "the law tends to fetishise the instant" at which a person makes a decision.
"I call this the 'no, no, no, no, no, yes' scenario. A patient may resist a medical recommendation quite insistently. But at the moment when they say 'yes', that can constitute consent. When someone is going along with the doctors, nobody ever questions their mental capacity."
For a philosopher, he says, the element of how time operates in decision-making is a rich and complex topic. But there are other ways to look at decision-making, which take in that person's history, medical context, their character traits over time and their ability to express themselves with help from others.
"My father-in-law suffers from Alzheimer's, and we often find ourselves in the situation of having to help him make decisions," explains Martin. "We may pretend that consent is something that individuals do by themselves, but that's a myth perpetuated by the law.
"My father-in-law is capable of making a lot of decisions for himself. But when he does, the decision-making involves a division of labour between him, his daughters, me, his psychiatrist and his care workers. If you think about it, making decisions in life is almost always a collective endeavour."
When the research concludes, Martin's team will conduct a knowledge transfer master class to be piloted at the Maudsley. "In my experience so far with this, physicians and lawyers and social welfare officers find it an enormous relief to be able to get some of those questions out in the open for discussion," he says.