The grey-areas on the deterministic-indeterministic spectrum

In her article on loss of a chance, Reece adopted a working understanding of determinism and indeterminism which showed two extremes which enabled her to illustrate the different types of causal process, but she reached the more nuanced conclusion that ‘a continuum between determinism and indeterminism is more plausible than a clear division’.95 _{It will be argued in this}

section that medical negligence cases involving misdiagnosis or mistreatment of existing illness do indeed fall somewhere in the middle of this spectrum. The physical causal process may well be deterministic, so once physical harm has occurred it is theoretically possible to discover the causes of this outcome. At the time of diagnosis it is also theoretically possible, with unlimited knowledge and understanding, to predict the outcome with certainty. But crucially at the time of diagnosis and treatment the practical reality is that both the claimant and the defendant doctor have only limited knowledge and understanding so they can only state the likelihood of a cure. Although they may be aware that the philosophical/scientific truth is that this is an epistemological probability, they both treat the patient as having a personal chance of cure. The

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patient may adapt his lifestyle to minimise risk factors and improve his chance of cure, the focus of the doctor’s duty of care is on treating the risk factors (i.e. the illness) in order to maximise the patient’s chance of being cured. This characteristic of the doctor’s duty of care means that the demands of interpersonal responsibility favour the recognition of this form of damage in order to achieve a coherent approach. The causal process is deterministic but in the context of this special relationship both parties treat it as being indeterministic, indeed the purpose of the defendant’s duty of care is premised on it being indeterministic. This means that the damage to this epistemological ‘chance’ is a loss that ought to be repaired under corrective justice.

Reece acknowledges that it is difficult to conclude that an event is indeterministic because ‘our inability to predict its occurrence could be either because the event is inherently unpredictable or because we have not yet found the complete set of necessary and sufficient causes’.96 _{She is}

willing to characterise an event as ‘quasi-indeterministic’ i.e. to the best of our knowledge indeterministic:

if and only if it could not have been predicted at any point in the past, it cannot be predicted in the present even given unlimited time, resources and evidence, and we cannot imagine how it would become predictable in the future, even given the success of present research programmes.97

This is clearly a very demanding definition. It sets a high threshold and means that most physical processes will be regarded as deterministic.

It is clear that a grey area exists if one compares the views of different authors regarding an event as familiar as the toss of a coin. Reece treats this as indeterministic, stating that ‘[t]ossing a coin does not cause the coin to land heads, but it does cause the chance that the coin will land heads’.98 _{In contrast, Beever regards it as deterministic, explaining ‘[w]hen the coin is in the air}

there is a fact of the matter as to which side it will land on. There is, then, no objective chance

96 _{ibid 194.} 97 _{ibid 194.} 98 _{ibid 206.}

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here whatsoever’.99 _{This highlights the fact that where it is theoretically possible to predict an}

outcome, but impossible to predict it given normal knowledge or experience, it is common to treat an event as being indeterministic.

Reece’s definition of determinism may be an acceptable theoretical and philosophical definition but it does not reflect the experience of the doctor and the patient. Even with his medical knowledge and understanding, the doctor is unable to predict the outcome with certainty, instead describing the patient as having a chance of recovery and then treating the illness. Providing appropriate treatment is the way the doctor finds out whether the patient could or could not be cured. As Lord Nicholls argued, the doctor regards the patient as having a chance of being cured, explaining:

the law should be exceedingly slow to disregard medical reality in the context of a legal duty whose very aim is to protect medical reality. In these cases the doctor’s duty to act in the best interests of his patient involves maximising the patient’s recovery prospects, and doing so whether the patient’s prospects are good or not so good.100

In a case such as Hotson the process is deterministic, and medical science has advanced enough to understand that it is the state of the blood vessels that determines whether the damage will occur. But, in any individual case, when the doctor commences treatment both he and the patient regard the outcome as involving a chance because they simply do not know whether sufficient blood vessels remain intact. Even with careful treatment the doctor cannot guarantee that the treatment will succeed or fail because there are factors beyond his control and because he does not know whether there are enough blood vessels remaining intact.

In a case such as Gregg it is even clearer that the doctor treats the patient as though he has a chance of recovering. When Mr Gregg was eventually referred to a specialist who diagnosed the

99 _{Beever, ‘Gregg v Scott’ (n39) 209.} 100 _{Gregg (HL) (n26) [42].}

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lump as cancer he was told that he had a 10-15percent chance of survival if treated.101 _Even

armed with knowledge of the extent and location of the cancer, and with understanding of factors that affect survival rates, the doctor was unable to say whether Mr Gregg was one of the 10-15 out of 100 who would survive or one of the 85-90 out of 100 who would die even with treatment.

Since this argument is based on the medical reality and shared experience of the doctor and patient, it would apply in all cases of misdiagnosis/mistreatment of existing illness. Since it is not an exceptional solution to a problem of proof of causation there would be no need to seek to circumscribe its application by reference to vague or arbitrary criteria. In contrast, the loss of chance argument for proportionate recovery would enable claimants to bypass the causation requirement, so its supporters have sought to limit its application by reference, for example to the degree of uncertainty in the disease. Jansen argues that ‘chance’ exists where there is ‘a genuine, unavoidable uncertainty, relative, of course, to standards of scientific knowledge’ so in his example the question of whether someone will survive a cardiac arrest ‘can only be answered in probabilities and is therefore best perceived in terms of chance and risk’.102 _{Similarly Lord}

Nicholls in Gregg suggested that a loss of chance approach to proportionate recovery was appropriate there but not in Hotson because the patient’s prospects in Gregg but not in Hotson were ‘fraught with a significant degree of medical uncertainty’.103 _{Lord Nicholls acknowledged}

that this might be criticised for being ‘an imprecise boundary’,104 _{and such criticism is arguably}

well-founded. Most cases of medical negligence will involve a degree of uncertainty surrounding causation and that is precisely why the law only requires proof on the balance of probabilities. If courts allowed proportionate recovery in some cases where they felt that the degree of uncertainty was great enough, decisions would essentially turn on whether the court felt that the

101 _{Gregg (CA) (n28) [13] (Latham LJ). This was his ‘chance’ at the time of diagnosis – by time of trial his chance was}

assessed at 20-30%.

102 _{Nils Jansen, ‘The Idea of a Lost Chance’ (1999) 19 OJLS 271, 279.} 103 _{Gregg (HL) (n26) [49].}

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claimant was deserving of help in avoiding difficulties of proof. In contrast, recognising that every patient who is already ill has a chance of being cured, and that this chance is something of value to him independently of the outcome (i.e. not leading to proportionate recovery for the physical harm) because at the time of treatment both the patient and the doctor see the outcome as being uncertain, then loss of chance would be recognised in every case where medical practice is to describe the patient as having a chance. When the concept of chance is analysed on its own terms as arising out of the considerations of interpersonal responsibility unique to the doctor/patient relationship there is no need to try to draw lines to limit it to being an exceptional approach.