Mental-State Defences: Insanity and Automatism

Chapter 2
Mental-State Defences: Insanity and Automatism

This chapter will set out the substantive criminal law in relation to the mental-state defence of insanity and the doctrine of automatism. The first part of the chapter will consider the role played by ‘knowledge’ in both the common-law and statutory formulations of the defence of insanity. The latter part of the chapter will consider the role played by ‘volition’ in the context of automatism, both as it relates to the criminal law’s voluntariness requirement and when it is subsumed under the insanity defence.

The defence of insanity

The M’Naghten rules

The common-law defence of insanity is governed by the so-called M’Naghten rules.¹ The M’Naghten rules form the basis for common-law and most statutory formulations of the insanity defence in Australia.² The M’Naghten rules arose in the context of judicial comment following the acquittal, on the grounds of insanity, of Daniel M’Naghten. M’Naghten had been charged with the murder of Prime Minister Peel’s secretary Edward Drummond, whom he had mistaken for the prime minister. M’Naghten was under the insane delusion that the Tory party was persecuting him and that he was in danger of being killed. In the light of the public outcry at the acquittal, the matter was debated in the House of Lords. In an attempt to elucidate the scope of the insanity defence the House in its legislative capacity subsequently put to the Law Lords certain questions. One particular question put to the Law Lords was the following: ‘In what terms ought the question be left to the jury as to the prisoner’s state of mind at the time when the act was committed?’ The answer provided by the judges to this particular question forms the basis of the defence of insanity in the common law world. In particular, the answer provided to this question stipulates that a person is not responsible for his or her crimes on the grounds of insanity if it is

clearly proved that, at the time of the committing of the act, the party accused was labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he [or she] was doing; or, if he [or she] did know it, that he [or she] did not know what he [or she] was doing was wrong.³

An example of a modern statutory formulation of the insanity defence is that provided for by the Victorian legislation:

20. Defence of Mental Impairment

(1) The defence of mental impairment is established for a person charged with an offence if, at the time of engaging in conduct constituting the offence, the person was suffering from a mental impairment that had the effect that –

(a) he or she did not know the nature and quality of the conduct; or

(b) he or she did not know that the conduct was wrong (that is, he or she could not reason with a moderate degree of sense and composure about whether the conduct, as perceived by reasonable people was wrong).

(2) If the defence of mental impairment is established the person must be found not guilty because of mental impairment.⁴

As stated, the M’Naghten rules and the Victorian statutory formulation of this provide for two possible lines of defence. Where it is shown that there was a condition considered to be a disease of the mind, or mental impairment, it is then necessary to show that it had one of two incapacitating effects. An accused may be held non-responsible where, because of a disease of the mind, he or she did not know the nature and quality of the act, or, if he or she did know the nature and quality of the act, he or she did not know it was ‘wrong’. Under either limb it has to be shown that the failure of knowledge arose from a defect of reason ensuing from a disease of the mind. Each of these matters will be considered below.⁵

Disease of the mind

According to the M’Naghten rules, it must be established that the defect of reason is caused by a disease of the mind. The mere fact that an accused suffers from a defect of reason in the relevant sense will not be sufficient for a finding that the person was not criminally responsible. A causal link between this and an underlying disease must also be established. The meaning of the term ‘disease of the mind’ is a legal rather than a psychiatric question.⁶ Whether a particular type of condition is to be characterized as a disease of the mind is a question of law. That is, the judge will direct the jury as to the meaning of ‘disease of the mind’. For example, a judge will rule on whether drug-induced psychosis is a disease of the mind for the purposes of the defence.⁷ The jury will decide the question of whether or not the accused was insane at the time of committing the criminal act. That is, the jury will determine on the basis of the evidence led whether the defendant was suffering from a disease of the mind, at the time of the offence, which resulted in the requisite incapacities. For example, the jury will decide whether the defendant’s behaviour is consistent with the condition known as schizophrenia, where such a condition satisfies the disease of the mind enquiry.

The requirement that a disease of the mind cause the defect of reason links the defect to an internal cause, an ‘underlying pathological infirmity of the mind … which can properly be termed mental illness, as distinct from the reaction of a healthy mind to extraordinary stimuli’.⁸ Consequently those ‘conditions of intense passion and other transient states attributable to the fault or to the nature of man’ will be excluded from the concept.⁹ For example, the defence will not be satisfied where the accused’s mental faculties have been impaired by an ‘external’ factor such as voluntary drug use. What is required is an internal infirmity or illness which affects an individual’s rational thought processes. There need be no actual disease in the sense of an organic disintegration of brain structure. ‘Mind’ is distinct from ‘brain’ and refers to the faculties of reason, memory and understanding.¹⁰ Ultimately, ‘the condition of the brain is irrelevant as is the question of whether the condition of the mind is curable or incurable, transitory or permanent’.¹¹ It will be sufficient to satisfy the requirement that the ‘functions of the understanding are through some cause, whether understandable or not, thrown into derangement or disorder’.¹² Stanley Yeo has remarked that the literal meaning of the word ‘disease’ does not cover those cases of mental deficiency which arise from a state of either arrested or incomplete mental development.¹³ As a result courts have broadly interpreted ‘disease of the mind’ so as to incorporate all cases resulting in cognitive deficiency satisfying the requirements of the M’Naghten rules whether due to disease or some other aetiology.¹⁴

Not all conditions which are clinically recognized as mental disorders will be covered by the expression ‘disease of the mind’. This will be regardless of whether or not such disorders have an organic basis.¹⁵ Even, purely physical diseases of only peripheral psychiatric interest, such as arteriosclerosis, epilepsy and diabetes, may satisfy the requirements of the term.¹⁶ The defence of insanity is not concerned with the classification of psychiatric dysfunction but with whether the legal question has been answered, namely, whether such a dysfunction is to be characterized as a disease of the mind. For example, in terms of psychiatric nosology, the symptoms of drug-induced psychosis constitute psychiatric dysfunction. However, such symptoms are not viewed as a disease of the mind for the purposes of the criminal law.¹⁷ Consequently, dysfunction arising from the voluntary use of drugs will not give rise to the operation of the defence of insanity. The issue of drug-induced psychosis and the defence of insanity will be discussed in more detail in Chapter 4.

Legislative formulations of the insanity defence may be distinguished as following one of two approaches in their treatment of the notion of disease of the mind: either by defining ‘disease of the mind’ according to a list of conditions or by employing terms which are broadly expressed.¹⁸ Where a list of conditions is provided, it will usually include ‘senility, intellectual disability, mental illness, brain damage and severe personality disorder’.¹⁹ The common-law concept of disease of the mind is incorporated into these formulations by their defining of the expression ‘mental illness’ so as to excuse only those mental states arising from some internal rather than external cause. For example, the West Australian provision defines ‘mental illness’ as follows: ‘Mental Illness means an underlying pathological infirmity of the mind, whether of short or long duration and whether permanent or temporary, but does not include a condition that results from the reaction of a healthy mind to extraordinary stimuli’.²⁰ Examples of ‘extraordinary stimuli’ in the definition above would include instances of trauma or substance abuse.

In contrast to the provision of a list of conditions, other jurisdictions use broadly expressed terms to clarify the common-law concept of disease of the mind which they do not further define.²¹ For example, the Victorian statute employs the expression ‘mental impairment’ which is left undefined.²² Stanley Yeo has suggested that these expressions have been left intentionally undefined in order to allow courts to interpret and apply them to the particular case in issue.²³

Chapter 3 will discuss in more detail the relevant factors to be considered in determining whether a particular condition satisfies the disease of the mind enquiry.

Defect of reason

As noted above, the M’Naghten rules will be satisfied where a disease of the mind causes a defect of reason. According to the M’Naghten rules, a defect of reason may result in an accused either not knowing the nature and quality of his or her act or not knowing that it is wrong. As commonly understood, the requirement of a defect of reason in the M’Naghten rules has been viewed as delimiting the scope of the defence within very narrow constraints.²⁴ In particular, ‘defect of reason’ has been held to refer only to the purely cognitive aspects of an accused’s behaviour.²⁵ It is a defect in the capacity for rational thought which is the primary focus of the expression. As a result of this interpretation, significant emotional or volitional deficiencies will not, in themselves, constitute a defect of reason.²⁶ However, as will be discussed later, such deficiencies may be the product of a relevant cognitive incapacity which will ground the defence. Consequently, on a strict application of the M’Naghten rules for the purposes of the insanity defence only states of cognitive disorder will be viewed as determinative.

This book will seek to determine whether those states of mental malfunctioning captured by the expression ‘defect of reason’ are too narrow to delineate adequately the range of incapacitating states of mental malfunction attendant upon a state of insanity. Consequently, a question this book will set out to answer is whether or not there are other effects besides cognitive incapacity arising from a disease of the mind to which the law should have regard. In particular, this book examines whether an accused’s inability to control his or her conduct arising from a state of mental disorder characterized as a disease of the mind should be recognized as sufficient to give rise to the insanity defence. This question will be considered in Chapter 5.

Nature and quality

An accused may be held non-responsible where, because of a disease of the mind, he or she is precluded from knowing the ‘nature and quality’ of his or her act.

The Court of Appeal in R v Codere²⁷ held that the ‘nature and quality’ phrase denoted the ‘physical character’ of an action as distinct from its moral aspects. A failure to know the physical character of an act has been held to mean that the defendant did ‘not know what he [or she] is doing’.²⁸ Similarly, the High Court of Australia has held that the phrase ‘nature and quality’ means ‘the capacity to comprehend the significance of the act of killing and of the acts by means of which it was done’.²⁹ Paradigmatic cases include the husband who in the belief that he is squeezing a lemon in fact strangles his wife.³⁰ Equally, a lack of knowledge may result in an individual believing that he or she is cutting a loaf of bread when in fact he or she is cutting another person’s arm.³¹ Such a defendant fails to understand the ‘nature and quality of his [or her] act’ in the sense that he or she does not know what he or she is doing.

However, the expression ‘nature and quality’ signifies something more than merely the surface features of the accused’s conduct. As expressed by the Canadian Supreme Court, ‘an accused may be aware of the physical character of his action (i.e. choking) without necessarily having the capacity to appreciate that, in nature and quality, the act will result in the death of a human being’.³² The expression ‘appreciate’ in place of ‘know’ has been interpreted as implying that a ‘deeper level of cognition’ on the part of an accused is required.³³ Such a ‘deeper level of cognition’ has been understood as including not only knowledge of the surface features of the act but also the consequences of such an act.

Instances may be imagined where the accused may know the surface features of his or her act, yet, as a result of a state of mental disorder, not know the consequences of the act. For example, an individual may be aware that he or she is choking another person without realizing that in so doing, he or she will bring about the death of a human being.³⁴ In R v Porter,³⁵ the common-law requirement of an accused’s lack of knowledge of the nature and quality of an act has been interpreted as consisting of both a lack of knowledge of the surface features of the act and its harmful consequences. In that case the High Court held that an accused is entitled to the defence of insanity where his or her mental disorder ‘was such as that he could not appreciate the physical thing he was doing and its consequences’.³⁶

Situations where an accused’s mind is so disturbed that he or she does not know the nature and quality of the act are rarely encountered in practice. As will be discussed in more detail in Chapter 3 when clinical accounts of mental disorder are considered, severe cases of mental disorder rarely preclude an individual from appreciating the character of his or her conduct. The problem in most cases of severe mental illness will not involve an individual’s lack of knowledge of the nature and quality of his or her act but rather the way in which such knowledge is processed.³⁷ Hence, in most instances it will not be an accused’s lack of knowledge of the nature and quality of his or her act that will ground a defence of insanity. Rather, it will be the way in which he or she processes such knowledge which will give rise to the defence. The central issue is generally whether in the context of his or her delusional thinking he or she knows that the paradigmatic act of killing another person is wrong. Consequently, that aspect of the rules concerned with an accused’s knowledge of the nature and quality of the act will not be commented on further in the course of the present work. Rather, this book will focus on that limb of the rules in respect of a defendant’s knowledge of the wrongness of his or her act.

A number of distinctions may be drawn in respect of an accused’s knowledge of the wrongness of his or her act. In particular, a distinction may be drawn between, on the one hand, that which may be known, the ‘object’ of knowledge, and, on the other, the cognitive processes constitutive of an agent knowing, the ‘nature’ of such knowledge. The following two sections will consider the object and nature of an accused’s knowledge of the wrongness of his or her act respectively.

The object of knowledge: moral or legal?

At common law, an accused must lack knowledge of the wrongness of his or her particular act for the defence of insanity to be established. The courts have differed in England and Australia as to whether or not the object of the accused’s knowledge means legally or morally wrong. In R v M’Naghten,³⁸ Lord Tindal CJ stated:

If the accused was conscious that the act was one which he ought not to do, and if that act was at the same time contrary to the law of the land, he is punishable; and the usual course therefore has been to leave the question to the jury, whether the party accused has a sufficient degree of reason to know that he was doing an act that was wrong.³⁹

In R v Codere,⁴⁰ Lord Reading CJ for the Court of Criminal Appeal sought to clarify the ambiguity of the above formulation by holding that:

Once it is clear that the appellant knew that the act was wrong in law, then he was doing an act which he was conscious he ought not to do, and as it was against the law, it was punishable by law; … The difficulty no doubt arises over the words ‘conscious that the act was one which he ought not to do’, but, looking at all the answers in M’Naghten’s case, it seems that if it is punishable by law it is an act which he ought not to do, and that is the meaning in which the phrase is used in that case.⁴¹

Subsequently in R v Windle,⁴² Lord Goddard CJ for the English Court of Appeal held that in respect of the law in England ‘wrong’ meant ‘contrary to law’:

Courts of law can only distinguish between that which is in accordance with law and that which is contrary to law. … The law cannot embark on the question, and it would be an unfortunate thing if it were left to juries to consider, whether some particular act was morally right or wrong. The test must be whether it is contrary to law.⁴³

So, the position in England is that what is meant by the object of knowledge in the M’Naghten rules is that the act is legally wrong.⁴⁴

However, the position differs with respect to Australian common law. The High Court in Stapleton v R⁴⁵ refused to apply Windle and held that ‘wrong’ was not to be defined narrowly as a legal wrong, the question instead being whether the accused ‘could not think rationally of the reasons which to ordinary people make that act right or wrong’.⁴⁶ Hence, in respect of an accused’s knowledge of the wrongness of his or her act, Australian courts have favoured a test of knowledge of moral rather than legal wrongness.⁴⁷ As expressed by Dixon J, in order to determine whether an accused lacks the requisite knowledge,

the question is whether he was able to appreciate the wrongness of the particular act he was doing. … If through a disease or defect or disorder of the mind he could not think rationally of the reasons which to ordinary people make that act right or wrong. If through the disordered condition of the mind he could not reason about the matter with a moderate degree of sense and composure it may be said that he could not know that what he was doing was wrong.⁴⁸

That is, in Australia, at common law, the accused is exempted from responsibility where, as a result of a disease of the mind, he or she could not ‘think rationally’ about whether his or her act was morally wrong. Where an accused is suffering from a disease of the mind making it impossible for him or her to reason with a ‘moderate degree of sense and composure’ about the normative implications of his or her action he or she will be taken not to know that the conduct as perceived by reasonable people was wrong.⁴⁹ This gloss on the phrase ‘could not know that what he [or she] was doing was wrong’ has been adopted in the formulation of several Australian jurisdictions.⁵⁰

In contrast, the relevant part of the Queensland, Western Australian and Tasmanian formulations of the defence reads that an accused will be held non-responsible for his or her conduct if due to mental disorder he or she was deprived of ‘the capacity to know that [he or she] ought not to do the act or make the omission’.⁵¹ The High Court has interpreted this clause as raising the issue of whether the accused lacked the capacity to know that his or her conduct ‘was wrong according to the ordinary standards adopted by reasonable men’.⁵² The distinction between an accused’s ‘capacity’ for knowledge as distinct from his or her ‘lack’ of knowledge will be discussed further in the following section.

What of the individual who believes that his or her acts are not wrong? Such an individual’s view of morality is not to be substituted for that of society. The issue will be decided according to whether or not, as a result of a disease of the mind, he or she knows that society regards his or her act as wrong. A person who knows that reasonable people would consider such conduct to be wrong will be taken to know that it is wrong, regardless of his or her own view of the morality of such conduct.⁵³ Even where an individual believes that his or her conduct is not morally wrong, the defence will not be available if he or she knows that such conduct is wrong according to the standard of reasonable people.⁵⁴ Alternatively, someone who believed that they were acting under divine command may know that what they are doing is legally wrong yet not be able to appreciate that it would be morally condemned. Such an individual lacks the capacity to understand the normative judgments of the community.⁵⁵

In summary, the English view is that an accused who seeks to raise the defence must be shown not to know that his or her act is a legal wrong. In contrast, the position in Australia is that ‘wrong’ is not to be interpreted according to the accused’s personal standards, but rather according to the standards of ordinary people. Nevertheless, the High Court in Stapleton noted that there would be little difference whether an accused’s understanding of what was wrong was measured in terms of knowing that his or her act was wrong in terms of contrary to law or wrong according to ordinary standards.⁵⁶ In most instances acts that are contrary to the law will also be contrary to morality. However, as the court noted, there are cases where an accused may know that an act is punishable by law yet not know that such an act is morally wrong according to ordinary standards.⁵⁷ An instance of such a case will be presented below.

The nature of knowledge: actual or capacity?

This section examines what is meant by the ‘nature’ of an accused’s knowledge of the wrongness of his or her particular act. The nature of an accused’s knowledge refers to the cognitive processes required on the part of an agent in order for him or her to know that an act is wrong. As put in R v Porter:⁵⁸

The question is whether he was able to appreciate the wrongness of the particular act he was doing. … If through a disease or defect or disorder of the mind he could not think rationally of the reasons which to ordinary people make that act right or wrong.

If through the disordered condition of the mind he could not reason about the matter with a moderate degree of sense and composure it may be said he could not know that what he was doing was wrong.⁵⁹

For an accused to ‘know that what he was doing was wrong’ is for him or her to ‘appreciate the wrongness of the particular act he was doing’. To ‘appreciate’ is to ‘think rationally’ which will require the defendant to ‘reason with a moderate degree of sense and composure’.

There are competing interpretations in Australian jurisdictions as to whether it is actual knowledge or a capacity for knowledge that is required. At common law, the M’Naghten rules require an examination of an accused’s actual knowledge of the wrongfulness of his or her act, namely, whether or not the crime which he or she committed was morally wrong.⁶⁰ In the language of the M’Naghten rules, ‘the party accused was labouring under such a defect of reason, from disease of the mind … that he did not know he was doing what was wrong’.⁶¹

Similarly, the Crimes (Mental Impairment and Unfitness to be Tried) Act 1997 (Vic) section 20(1)(b) refers to an accused who ‘did not know that the conduct was wrong (that is, he or she could not reason with a moderate degree of sense and composure about whether the conduct, as perceived by reasonable people, was wrong)’.⁶² The Victorian Act has been held to be declarative of the common law.⁶³ Similarly the Northern Territory Code requires that the accused ‘did not know that the conduct was wrong’.⁶⁴ Further, the Commonwealth Code,⁶⁵ the ACT Code⁶⁶ and the South Australian Act⁶⁷ all require, for the defence to be established, that the defendant lack actual knowledge of the wrongness of his or her act at the time of the offence. Section 7.3(1)(b) of the Commonwealth Criminal Code reads:

A person is not criminally responsible for an offence if … (b) the person did not know that the conduct was wrong (that is, the person could not reason with a moderate degree of sense and composure about whether the conduct, as perceived by reasonable people was wrong).

The language employed by the Commonwealth Code is identical to that employed in the Victorian Act: ‘did not know that the conduct was wrong’. Equally, the code borrows from Dixon J’s judgment in Porter in requiring a person to ‘reason with a moderate degree of sense and composure’.⁶⁸ Both the commentary to section 302 ‘Mental Impairment’ of the Commonwealth Code⁶⁹ and the published Guide for Practitioners⁷⁰ make it clear that this formulation ‘moves away from the existing Griffith Code concepts based on capacity in favour of tests phrased in terms of what D actually knew’.⁷¹ That is, the Commonwealth Code requires actual knowledge, rather than a capacity for knowledge, on the part of a defendant.

In contrast, an approach calling for a capacity-based interpretation of the knowledge requirement is to be found in the Griffith Code jurisdictions. In those jurisdictions it must be shown that the accused lacked the ‘capacity to know that the person ought not to do the act or make the omission’.⁷² Analogously, the Tasmanian Code requires that the accused was ‘incapable of knowing that the act or omission was one that he or she ought not to do or make’.⁷³ It has been suggested that a test of incapacity restricts the defence of insanity to a greater degree than a test of lack of actual knowledge: a person may possess the capacity to know the wrongness of his or her act yet not be able to exercise it at the time of the offence.⁷⁴ While the expression ‘capacity’ is used in several jurisdictions it is argued that it is only because courts have ignored the restrictive narrowness of a capacity-based approach to the insanity defence that the defence has not been restricted even further than it currently is.⁷⁵

Another issue raised by the nature of an accused’s knowledge is the degree of impairment required to an accused’s mental functioning before the defence of insanity will be established. Stanley Yeo has suggested that in order to support the defence of insanity a ‘very high degree of mental impairment is required to sufficiently eliminate these capacities’.⁷⁶ It is because the defence results in a state of non-responsibility or total exemption from criminal responsibility, that a very high degree of mental impairment will be required in order to establish the defence.⁷⁷ It will only be where such a level of impairment results that it would be unwarranted to attribute any blame to an accused for failing to act according to the law. A lesser degree of incapacity should result in a finding of diminished responsibility rather than one of non-responsibility.⁷⁸

It is submitted that similar observations should apply in respect of the nature of an accused’s inability to control his or her conduct as a result of a state of volitional impairment characterized as a disease of the mind.⁷⁹ That is, a lack of control rather than incapacity to control conduct should be sufficient to raise the defence. Further, a very high degree rather than some lesser degree of impairment should be required on the part of an accused before he or she will be permitted to raise the defence. I will return to this issue in the context of the formulated defence of impaired consciousness in Chapter 6.

The next section will consider the implications of the above analysis of the object and nature of an accused’s knowledge of the wrongness of his or her acts.

Clarifying ‘knowledge’

1. Actual knowledge of legal wrong: the accused did affirmatively believe that the act was not a legal wrong: Windle,⁸⁰ Codere,⁸¹ ‘once it is clear that the appellant knew that the act was wrong in law, then he was doing an act which he was conscious he ought not to do, and as it was against the law, it was punishable by law’.⁸²

2. Actual knowledge of moral wrong: the accused did affirmatively believe that the act was not a moral wrong: Cth Code: ‘the person did not know that the conduct was wrong’,⁸³ ACT Code,⁸⁴ NT Code,⁸⁵ SA Act,⁸⁶ Vic Act,⁸⁷ Porter,⁸⁸ Stapleton.⁸⁹

3. Capacity for knowledge of legal wrong: the accused could not reason about the matter, that is, whether the act was a legal wrong, with a moderate degree of sense and composure: hypothetical example: ‘Murder is not a criminal offence, as my mother told me so’. In mistaking his or her mother’s advice for legal authority the accused reveals his or her incapacity to reason about the legal wrongness of the act.

4. Capacity for knowledge of moral wrong: the accused could not reason about the matter, that is, whether the act was a moral wrong, with a moderate degree of sense and composure: Griffith Codes,⁹⁰ Tas Code.⁹¹

Arranged schematically the above analysis reveals the following combinations:

Table 2.1 Matrix of possibilities 1: object and nature of knowledge

The following section will seek to apply the above analysis to a particular case of mental disorder in order to better understand what might constitute the ‘legal standard of disorder of the mind sufficient to afford a ground of irresponsibility for a crime’.⁹²

Case study: R v Hadfield

In providing jury directions in Porter, Dixon J sought to explain how an accused may fail to

appreciate the wrongness of the particular act he was doing … if through a disease or defect or disorder of the mind he could not think rationally of the reasons which to ordinary people make that act right or wrong. If through the disordered condition of the mind he could not reason about the matter with a moderate degree of sense and composure it may be said that what he was doing was wrong.⁹³

While to ‘appreciate’ was held to mean ‘think rationally’, and this was further defined as to ‘reason with a moderate degree of sense and composure’,⁹⁴ Dixon J failed to enunciate the senses in which an individual may be said to think rationally. In particular, the expression ‘think rationally’ fails to articulate a distinction that may be drawn between the admission of relevant considerations, on the one hand, and the weighing of such considerations, on the other.

For the purposes of the present discussion, I will take ‘relevant considerations’ to mean premises which are not delusionally flawed, that is, premises that are not the result of delusions arising from a state of mental disorder.⁹⁵ Hence, an accused may think rationally in either of the following senses: admitting relevant considerations, that is, non-delusionally flawed premises, or reasoning soundly with or weighing correctly a given set of premises notwithstanding the nature of such premises.

As a result of the above analysis the ‘legal standard of disorder’ appealed to by Dixon J in Porter may refer to the standard of lucid reasoning, in the sense of practical reason, or the standard of admitting only non-delusionally flawed premises or both. The significance of this distinction becomes apparent where an accused acts on a delusionally flawed premise in a means-end rational fashion. To suggest that such an accused is rational is to ignore one particular aspect of what it means to ‘think rationally’, namely, that the reasons for action which an individual admits for consideration are not delusionally flawed. The case of R v Hadfield is illustrative of this distinction.⁹⁶

Hadfield held the delusional belief that he was under divine instruction to die in order to save the world. As he considered the act of suicide a mortal sin, he decided to shoot at King George III and in this way bring about his own death for the capital offence of regicide. Lord Kenyon CJ held that Hadfield was insane at the time he did the act and ordered the jury to bring a verdict of not guilty subject to detention in custody given his dangerousness.⁹⁷ The case is important as it seems to provide the earliest instance of a reported case involving an acquittal of a defendant suffering from a diagnosable form of schizophrenia. Equally Hadfield provides a clear indication that it was no longer a requirement that only those totally deprived of understanding, or ‘wild beasts’, were subject to the defence.⁹⁸ In Hadfield, the fact that the accused was able to discern that suicide was a sin indicated that he had not lost all understanding of the difference between right and wrong.⁹⁹

Hadfield failed to think rationally and was eligible for the defence given his admission of a delusionally flawed premise, namely, the messianic delusion that by bringing about his own execution he would save the world. Once such an irrelevant consideration was admitted, it was a premise in his practical reasoning leading to his decision to shoot the king. While Hadfield’s thinking reflected means-end rationality, the delusionally flawed premise on which it was based was not a consideration which a rational person would have admitted as part of his or her thinking.

This is not to suggest that before an individual may be said not to think rationally his or her reasons for action must fail to reveal a recognizable pattern of coherence with other extant reasons. While a lack of a recognizable pattern of coherence may constitute a sufficient condition of severe mental illness, it is not a necessary condition of such illness. For example, certain varieties of severe mental illness such as paranoid schizophrenia may give rise to an encapsulated delusional belief system that reveals a great degree of inner coherence.¹⁰⁰ In such cases the delusional beliefs may even be supported by the ‘evidence’ of accompanying hallucinations.¹⁰¹

Hadfield is an instance of that class of case remarked on by the High Court in Stapleton, where

[while] the insane motives of the defendant arise from [a] complete incapacity to reason as to what is right or wrong (his insane judgment even treating the act as one of inexorable obligation or inescapable necessity) he may yet have at the back of his mind an awareness that the act he proposes to do is punishable by law.¹⁰²

It was Hadfield’s knowledge of the illegality of his action which prompted him to shoot at King George. Hadfield shot at the king precisely because he knew that it was illegal and that it would result in his own death for the capital offence of treason. However, given his delusional belief that he was acting under divine providence, Hadfield did not know that his act was morally wrong according to ordinary standards. Believing that he had been commanded by a higher authority to kill the king in order to fulfil a messianic belief, Hadfield lacked knowledge of the moral wrongness of his act. The case of Hadfield demonstrates that the ability to tell legal right from legal wrong is not necessarily excluded by insanity but that this ability often co-exists with serious mental disorder.¹⁰³

So how is Dixon J’s reference to the ‘legal standard of disorder of the mind which is sufficient to afford a ground of irresponsibility for a crime’ to be understood?¹⁰⁴ As detailed above, a person will be said to think rationally not only where his or her reason admits relevant considerations, that is, non-delusionally flawed premises, but also where he or she reasons soundly with such a given set of premises. Consequently, the case of Hadfield provides an apposite opportunity to assess the ability of each of the different jurisdictional formulations of the defence to accommodate a paradigmatic instance of severe mental disorder.¹⁰⁵

As applied to the case of Hadfield the matrix of possibilities outlined above detailing the various combinations of the object and nature of knowledge produces the following results:

1. Actual knowledge of legal wrong: Hadfield had actual knowledge that his act was legally wrong, consequently, he would not have a defence under English law as per Codere and Windle.

2. Actual knowledge of moral wrong: as Hadfield believed that his act was in response to the higher authority of divine providence Hadfield lacked actual knowledge that it was morally wrong. However, it remains an open question whether Hadfield knew that reasonable people would consider the conduct to be wrong. If he knew that reasonable people would consider his conduct to be wrong, he would be taken to know that it is wrong. Consequently, Hadfield may have a defence under the Commonwealth Code, ACT Code, NT Code, SA Act, Vic Act and the M’Naghten rules.

3. Capacity for knowledge of legal wrong: the fact that Hadfield actually knew it was illegal to shoot the king does not necessarily mean that he had the capacity for knowledge of legal wrong. Nevertheless, Hadfield would probably have no defence under the hypothetical defence calling for a lack of capacity for knowledge of legal wrong, as he was able to reason with a moderate degree of sense and composure in relation to such legal wrong.

4. Capacity for knowledge of moral wrong: if the admission of a delusionally flawed premise in a defendant’s reasoning is sufficient to preclude him or her from thinking rationally Hadfield lacked the capacity for knowledge of moral wrong. Hence, Hadfield may have had a defence under the Griffith Code and Tasmanian Code.

Table 2.2 Matrix of possibilities 2: R v Hadfield