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A Rope Stretched Over an Abyss:
Ethics, Law and Neuroscience

by Pierre Pouget


The dream of a complete noesis of the natural world is probably one of the most and profound aspirations of the human species, and even if the word 'scientist' was only introduced in 1840, this desire to understand the rules governing our physical world was expressed in the earlier stage of human civilization. As Franciscan friar Bacon emphasized in the middle of the 13th centuries, 'The strongest argument proves nothing so long as the conclusions are unverified by experience'.[1]

Yet the scientific approach of the medicine has since then always faced difficulties in undertaking those experiments.

An important step during medical training is the dissection of human or animal cadavers. Over the course of the history this practice has been often viewed as both morally and legally unacceptable. In fact, in the city of Alexandria in ancient Egypt, where Herophilos and others explored the nervous system, the circulatory system and the anatomy of the eye, human dissection was forbidden as it was later throughout Greece and Rome. This legal interdiction had important consequences, and despite major discoveries realized in ancient Egypt, Galen (then later Hyppocratus in Greece), had to face a massive handicap in studying human physiology and anatomy. Unfortunately some of those works were seriously compromised.

The controversy only ended nearly 1,400 years later, when Vesalius introduced into Europe the scientific examination of human anatomy. The Belgium anatomist who spent several years protected at the imperial court of Charles V in order to exert his talent as a surgeon, definitively marked a new consideration of the conception of medicine. Those researches were difficult. In fact Vesalius was harassed by the Church all his life, and most of his research was possible only as physician to Emperor Charles V.

Two centuries later, in England, Vesalius was succeeded by William Harvey whose 1628 book Exercitatio Anatomica de Motus Cordis et Sanguinis in Animalibus demonstrated that the heart was the center of the circulatory process, that the same blood flows through both veins and arteries, and that the blood makes a complete circuit throughout the body.[2] To achieve these observations, William Harvey practiced numerous animal autopsies and vivisections. For the quality and the organization of his research Harvey is sometimes considered as the inventor of the modern laboratory. Following Harvey, during most of the 19th century and even the early 20th century, the increasing use of animals as subjects of scientific research was then universally accepted and approved.

In 1831, a British physiologist whose name is associated with the theory of reflex arc mediated by the spinal cord, proposed a critical aim in relation to animals as subjects of scientific research. Marshall Hall at that time was still working on the reflex function but the same year he proposed five principles that he believed should govern all animal experimentation. Since those recommendations are today formally instituted in the British Animals (Scientific Procedures) Act and the U.S. Animal Welfare Act, it is important to briefly state them:

1. An experiment should never be performed if the necessary information can be obtained by observations.

2. No experiment should be performed without a clearly defined and obtainable objective.

3. Scientists should be well-informed about the work of their predecessors and peers in order to avoid unnecessary repetition of an experiment.

4. Justifiable experiments should be carried out with the least possible infliction of suffering (often through the use of lower, less sentient animals).

5. Every experiment should be performed under circumstances that would provide the clearest possible results, thereby diminishing the need for repetition of experiments.

During the same period, Hall also proposed the founding of a scientific society to oversee publication of research results and recommended that 'the results of experimentation be laid before the public in the simplest, plainest terms'.[3] In general, Hall was criticised by those who disapproved of animal experimentation, both within and without the medical community.

Ethics, Law and Neuro-ethics: influences on Neurosciences

Marshall Hall's recommendations are today an important part of what is considered by the public society as an ethics of scientific practice. In terms of definition, the notion of ethics refers to the second-order and reflective consideration of our moral beliefs and practices, by contrast to morality which refers to the first-order beliefs and practices about right and wrong by means of which we guide our behavior. In others words, ethics may be defined as the explicit, philosophical reflection on moral beliefs and practices. Generally speaking, the difference between ethics and morality is similar to the difference between psychology and mind. Ethics is a conscious stepping back and reflecting on morality, just as psychology is a scientific reflection on mind.

In academic terms, ethics is a branch of philosophy concerned with morals and human conduct. With the recent development of neurosciences the notion of 'neuro-ethics' arose in order to address moral and social issues concerning the conduct of research in the neurosciences and biological psychology including their clinical applications.

Typical issues in neuro-ethics include the ethics of conducting research into novel interventions in the brain itself, but also the question of the ethical and social implications of the transformed 'models of man' arising from the findings of neuroscience. Neuro-ethics is also concerned by the meaning and application of brain imaging in the courts or schools as well as the ethical and social aspects of the clinical and public health treatment of psychiatric and neurological disorders in the light of modern research. Finally, the implications of modern neuroscience for our understanding of the basis of morality and social behaviour have given rise to the problem of the transformations of our concepts of free will and responsibility. For the purpose of this article we will only discuss the critical implication of this last point.

Since neuro-ethics refers to a specific aspect of ethics, the specification of what definition of ethics we will rely on in this article is essential. Most authorship of ethical codes distinguishes codes from civil or criminal laws. In fact, codes of ethics are commonly compiled primarily by members of the professions to whom they apply when laws are written by elected officials. An important difference between ethics and law resides in the aspirational quality of ethics, contrasted with minimal standards set by the law. It is incorrect to assume automatically that 'if it's legal, it's ethical.'

A law-abiding physician is not necessarily highly skilled or compassionate. The aspirational nature of ethical codes involves questions such as: 'What virtues and acts must characterize the best of our profession?' Sometimes one might have to choose between ethics and law. While ethics generally sets the bar for conduct at a different level than law, it would be incorrect to say that the law is unconcerned with values. The adage 'you can't legislate morality' is false in that every statute mandates some act or restraint in order to preserve a moral value. In most countries, the law prohibits wearing firearms in public in order to protect human life.

By contrast, what morally true cannot always be subject to law. Nor should it be. A society in which every good act is mandated by law would be tyranny. In today's life, meaningful moral action requires reflection, choice, or even failure. In contrast, ethical codes should not be seen as requiring perfection, but as statements of those purposes toward which one aims throughout the course of one's professional life. Generally speaking, however, values inform both ethics and law: ethics focusing on particular professional values, and law setting minimal standards of conduct to preserve the common good. So while ethics can govern the profession of a particular group of neuroscientists, neuroscience is also governed by law.

As we mentioned earlier, the law is the usual term that defines a rule, made by a government or political group that governs a society. Those rules are used to regulate the way in which a society behaves, or the whole system of such rules: such as laws against driving without a valid driving licence. In neuroscience, law did in fact precede the introduction of ethics. For instance, the first law written specifically to regulate animal experimentation was written in Great Britain's 1876: The Cruelty to Animals Act.

The 1876 law, which implicitly approved animal experimentation at the same time as it set up a system of licensing and certification, was replaced by the Animals (Scientific Procedures) Act of 1986, which specifically states that 'The Secretary of State shall not grant a project license until he is satisfied that the applicant has given adequate consideration to the feasibility of achieving the purpose of the programme to be specified in the license by means not involving the use of protected animals' (Animal Welfare, UFAW, Vol. 1, No. 2, 1992). In the United States, the 1966 Animal Welfare Act, amended in 1970, 1976, 1986, 1989, and 1991, set standards for laboratory animals, including rats, mice, and birds. On January 8, 1992 the U.S. District Court in Washington, DC ruled that the U.S. Department of Agriculture had been violating the Animal Welfare Act by not enforcing its provisions as they relate to these animals.

On a liberal view, society must not interfere with scientific questions or how scientists behave towards one another. In other words, investigation in science should not be limited by law. But society certainly does have an interest in protecting vulnerable subjects. On that view, neuro-ethics can be defined as this abyssal ocean between the two continents represented by law and neuroscience.

As shown by the modifications of law in the mid of the 20th century in most contemporary societies, classical researches on ethics were concerned mainly with invasive medical and physiological research, and secondarily with the ethics of some psychological, social psychological and anthropological research. Those concerns were certainly driven by the hypothetical revolution that those invasive research might imply.

To illustrate this idea, let's suppose that a precise set of neural imaging correlates of lying has been defined. For some purposes in psychological research it could be more or less immediately apparent to the researcher when the imaging subject is lying, even if the topic of the research is something quite different. Since part of the ethics of research involves seeking only the information required in the research, this could be considered as a breach of privacy. There are long-standing questions about the ethics of using a technology to detect lying, in the courts, in interrogation, or for other purposes, and whether evidence obtained in this way would or should be admissible or usable in making police inquiries. From the point of view of neuroscientists and many social scientists this is inevitably a biased perspective: it is clear that a social science take on the neurosciences will be more descriptive and explanatory than normative. Even within this perspective, however, it would be essential for a social science to understand the findings of neuroscience.

Neurosciences and its influences on Ethics, Law and Neuro-ethics

The concepts of 'moral' and 'responsibility' are explicitly present in many of the earliest surviving Greek texts (the Homeric epics). In those texts, both human and superhuman agents are often regarded as fair targets of praise and blame on the basis of how they have behaved. Sometimes a behavior is excused because of the presence of some factor that has undermined his control.[4]

Reflection on these factors gave rise to fatalism, the view that one's future or some aspect of it is predetermined, in such a way as to make one's particular deliberations, choices and actions irrelevant to whether that particular future is realized or not. If some particular outcome is destined, then it seems that the agent concerned could not be morally responsible for that outcome. Likewise, if fatalism is accepted with respect to all human futures, then it would seems that no human agent could be morally responsible for anything. Though this mark of fatalism has sometimes exerted significant historical influence, most philosophers have rejected it on the grounds that there is no good reason to think that our futures are destined in the sense that they will expand no matter what particular deliberations we engage in, choices we make, or actions we perform.[5]

As often, when looking among the earliest surviving Greek texts, Aristotle seems to be the first to construct explicitly a theory of moral responsibility. In the course of his discussion on human virtues and their corresponding vices, Aristotle starts in Nicomachean ethics to explore their foundations.[6] For Aristotle, only a certain kind of agent qualifies as a moral agent and is thus properly subject to ascriptions of responsibility, namely, one who possess a capacity for decision.

This consideration still remains essential and even today in the contemporary Anglo-American legal tradition, one of the requirements for criminal punishment is showing that the accused meets a test for being able to act responsibly. The failure to meet that requirement is a possible defense to a criminal prosecution. There are two basic components to the test: a cognitive requirement and a volitional requirement. The cognitive component focuses on whether the offender had the capacity to understand the wrongful and or unlawful nature of the criminal act. The volitional component asks whether or not the offender had the ability to control whether or not he committed the criminal act.

Generally, only people suffering from extreme and obvious deficits are able successfully to invoke the defense; and often not even then.[7] This concept of personal responsibility largely enlightened individualism but we should remember, that this conception was a late development of our legal system, and that its remains unpopular in many parts of the world today. It is important to keep in mind that the intuitive psychology idea of human action we possess is definitively the product of such enlightenment.

The neuroscience studies of decision-making and impulse control have major implications for the legal system. Those topics vary, including prediction of behavior, neuropsychiatric instruments that can be used for help in skills determinations, improvement in lie detection or even detection of brain death. Being able to enhance specific skills may raise the possibility of mandated enhancement, such as requiring people to take an antidepressant drug to make them less angry or irritable. Electrode stimulation of medio-frontal part of the cortex can temporarily modify the behavior of a macaque monkey[8][9] and we can imagine some procedures to modify the brain in order to treat addictions.[10]

In many aspects, the potential for discrimination based on neuroscientific tests and procedures raise serious issues regarding the exceptional treatment of individuals. Questions of privacy and confidentiality are also problematic, such as the extensive information gathered in a single imaging procedure. If admissible, are there other reasons for a court for not using the information that future neuroscience finding may be able to provide? Should a court allow testimony that a person has a superior memory or inferior activity of brain control? Should we introduce the possibility of refusing neuroscientific tests?

If people's actions are caused by factors for which they are not responsible, how can they be held responsible for actions that occur as a result of these factors? Neurophysiological experiments show that before a subject is even consciously aware of a decision to perform an act, the brain was active. The brain, as a physical organ is carrying on the ongoing action before the consciousness and awareness of the subject.[11] So then, can there be free choice in a deterministic scientific world of explanation?

When a violent act occurs, the quest is not simply to understand it as an activity of neurons but to assess responsibility. However, the point where the ability to inhibit an act is impaired is not clear. Of course, social rules are not based on neuroscientific findings and responsibility is a social construct. But recent neuroscientific findings raise some issues for the legal system that cannot be ignored. Old or recent discussions of these issues leave the impression of three disparate approaches with their own conceptions and projections. First, at a philosophical level, the debates about 'free will' and its perception in terms of determinism have not been fully resolved. Secondly, the law and more generally the entire legal system assesses responsibility of people as intentional agents governed by reason and goals. Finally, the neuroscience and its extraordinary development is now permitting to raises questions about the functioning of the brain and its mysterious relationship to the mind.

The Case of Mr. Puppet

In their recent paper, to illustrate the profound implication of responsibility in neuroscience, Green and Cohen (2004) used the case of a certain 'Mr. Puppet'. 'Mr. Puppet' is a criminal designed by a group of scientists through tight genetic and environmental control.[12] Having being arrested, Mr. Puppet will be judged for his unacceptable social behavior. The leader of the group of scientists is called to the stand by the defense, and here is what Greene and Cohen had him say:

It is very simple, really. I designed him. I carefully selected every gene in his body and carefully scripted every significant event in his life so that he would become precisely what he is today. I selected his mother knowing that she would let him cry for hours and hours before picking him up. I carefully selected each of his relatives, teachers, friends, enemies, etc., and told them exactly what to say to him and how to treat him. Things generally went as planned, but not always. For example, the angry letters written to his dead father were not supposed to appear until he was fourteen, but by the end of his thirteenth year he had already written four of them. In retrospect I think this was because of a handful of substitutions I made to his eighth chromosome. At any rate, my plans for him succeeded, as they have for 95% of the people I've designed. I assure you that the accused deserves none of the credit.

Could a change in the chromosome determine the timing of a nasty letter written? Nothing in the genome does contain all the information that will specify any particular action. The fact is that even if the environmental regulations are impossible to fully apprehend and control, Greene and Cohen illustrate how it is difficult to consider Mr. Puppet to be responsible for his actions. Because those 'forces beyond his control played a dominant role in causing him to commit the crimes, it is hard to think of him as anything more than a pawn.'

Law and liberty

As illustrated in the preceding text from Greene and Cohen, the notion of free will implies an ability of exerting control based on volition. Neuroscience will not change this fact. In order to solve this problem over history, a distinction has been made between responsibility understood as attributability and responsibility as accountability.

The central idea to be able to judge whether or not an agent is responsible for an action in the sense of attributability, is to examine whether this particular action illustrate important information about the nature of the agent[13] (Watson 1996). In other words, to regard an agent in the attributability sense of responsibility is simply to believe that the merit or fault identified properly belongs to the agent. On the other hand, while responsibility can be shared among group of subjects, accountability cannot. The idea being that there is no 'shared accountability'. Discussion of the place and role of the reactive attitudes in human life continues to be a central theme in accounts of the concept of responsibility. What is certain is that the interest of neuroscience in apprehending the concept of moral responsibility and its application would certainly be an essential element for the future of our society.

Concluding discussion

The refinement and the development of experimental techniques in neurosciences now permits without too much difficulty observation of the level of activity of clearly defined regions of the brain of humans or animals during the performance of various tasks. By recording the activity of single neurons, scalp potential or variation of blood flow, one can today, literally, observe how one's own brain is thinking.

At the level of the cells, we are familiar today with the nature of the nerve influx and the various electrical phenomena which confer upon the neuron its properties of excitability and its information-processing capabilities. At the molecular level, in addition to identifying the structure of the channels, neurotransmitters and their receivers, the identification of an abundance of molecules which interact in cascades enables us to understand the functional and molecular substrates of fundamental phenomena such as pleasure, suffering, dependence, memory and the formation of cognitive maps in the brain.

Genetics has also been particularly fertile in the area of the neurosciences, revealing families of genes for the enzymes, receptors and linking proteins which take care of the different neuronal functions. The discovery of regulating genes, which are responsible for the development of the brain in response to exposure to the influences of its environment, holds out considerable prospects for the understanding of the phylogenesis of the brain.

Should we consider the neurosciences to be a poisoned chalice on which the worst forms of ideology may be expressed? Looking to history has shown that if such temptations of using scientific discoveries for atrocious reasons may arise at a specific time, they never become part of the foundations of human society. The purpose of this article was to examine the complex relationship that neuroscience has with ethics and law and to present with optimism the wonderful but critical challenge that our society will have to face with in order to resolve how ethics and law should influence neuroscience.

As discussed by Cohen and Green (2004, but also see e.g. Churchland 1981; Bisiach, 1988), in the next decades our society will undoubtedly have to reconcile the discoveries of neuroscience discoveries and the determinism of the brain's function with the current conceptions or interpretations of the law and notion of responsibility.[14][15] It is also important to underline that at the same time, reactions from our society may force our legal system to adapt in order to restrict what is considered acceptable as an experimental study in neuroscience. Already, today an increasing number of regulations and laws influence the way the research in neurosciences is carried out.

Once again, although many people believe that, in principle, human behavior is the physical result of a causally determined chain of biophysical events, most people put that aside when making moral judgments or casting their vote.


1. Bacon R. (1265). Opus Majus. Translated in English by Belle Burke Robert (1928). Heyl, Paul R. Publication.

2. Harvey W. (1628). Exercitatio Anatomica de Motus Cordis et Sanguinis in Animalibus. Translated by Robert Willis (1993). New York: P.F. Collier & Son Company.

3. Rupke NA. (1987). Vivisection in Historical perspective. by N.A. Rupke. Beckenham: Croom Helm.

4. Homer. The Odyssey, translated by Edward McCrorie (2004). Baltimore: Johns Hopkins University Press.

5. Sartre (1948). Existentialism Is a Humanism. Yale Univ Press 1953.

6. Aristotle. Nicomachean ethics. Translated by W.D. Ross. 2006.

7. Lewis DO, Pincus JH, Feldman M, Jackson L, Bard B. Psychiatric, neurological, and psychoeducational characteristics of 15 death row inmates in the United States. AmJ Psychiatry 1986;143:838-45.

8. Histed MH., Miller EK. (2006). Microstimulation of frontal cortex can reorder a remembered spatial sequence. Plos Biol. May; 4(5):e134.

9. Stuphorn V., Schall JD. Executive control of countermanding saccades by the supplementary eye field. Nat Neurosci. 2006 Jul;9(7):925-31.

10. Haber SB, Kim KS, Mailly P, Calzavara R. (2006). Reward-related cortical inputs define a large striatal region in primates that interface with associative cortical connections, providing a substrate for incentive-based learning. J Neurosci. Aug 9;26(32):8368-76.

11. Libet, B., Gleason, C. A., Wright, E. W., and Pearl, D. K. (1983). Time of conscious intention to act in relation to onset of cerebral activity (readiness-potential). The unconscious initiation of a freely voluntary act. Brain, 106:623-642.

12. Greene, J. D., Cohen J. D. (2004) For the law, neuroscience changes nothing and everything. Philosophical Transactions of the Royal Society of London B, 359, 1775-17785.

13. Watson, Gary, 1996, 'Two Faces of Responsibility.' Philosophical Topics 24: 227-248.

14. Bisiach, E. (1988). The (haunted) brain and consciousness. In (A. Marcel and E. Bisiach, eds) Consciousness in Contemporary Science. Oxford University Press.

15. Churchland, P. S. (1981). On the alleged backwards referral of experiences and its relevance to the mind-body problem. Philosophy of Science, 48:165-181.

© Pierre Pouget 2008


Center for Integrative & Cognitive Neuroscience
Vanderbilt Vision Research Center
Department of Psychology
Vanderbilt University, Nashville, TN 37203