Objectivity in Biomedical Sciences PDF

# M8: PHILOSOPHIE DES SCIENCES ## Fiche de cours **L'objectivité dans les sciences biomédicales** ### Introduction * New methods and tools aim to standardize and make objective the results. * Allowing for a certain reproducibility * The scientifization of medicine * The question of wha...

# M8: PHILOSOPHIE DES SCIENCES ## Fiche de cours **L'objectivité dans les sciences biomédicales** ### Introduction * New methods and tools aim to standardize and make objective the results. * Allowing for a certain reproducibility * The scientifization of medicine * The question of what objectivity really is * The question of whether this objectivity has always been uniform * Possible evolutions of the meaning given to this term. * Authors of *Objectivity*, a work on the history and philosophy of science, 2007 * In medicine, among other sciences * The thesis that the advent of objectivity goes hand in hand with a new way of representing, seeing, scientific phenomena. * Intrication between representation, image and objectivity. ### Triple movement of objectivity * In the medical sciences since the mid-19th century. 1. Mechanical objectivity 2. Subjectivity 3. Objectivity as reasoned judgment * Link with the clinic * Aim of objectivity by the doctor in their clinical approach, always present in our time. ### Mechanical objectivity of the 19th century as a way to escape from Romantic idealism #### Development of new instruments in the 19th century * **Aim**: To offer a new objectivity to medical analysis. * **Specificity**: Mechanical nature of the instruments * Possibility of use by any layperson * High visibility of the promoters of these inventions * Specificity verified by experience today, with the use of instruments by patients themselves, in an ambulatory setting. * Reason for the opposition of clinicians to the Bernardian approach to medicine * **Example**: Inflatable manometer, still used today, although in a modernized version. ### The context of "Truth from nature" * **Highly idealized images**: * Highly prevalent images called "Truths from nature" * Made by artists for a scientific purpose * Works of memory = representations of nature in all its truth * It is impossible to keep every detail of an anatomical function, hence the need to record them through drawing. * Images still present today, even if they no longer make as much sense. * More often seen as curiosities without scientific purpose: realistic photographs * Works of art found in exhibitions. * **Pathological anatomy of the human body**: * Work written by Jean Cruveilhier, published in 1829 and 1842 * First doctor to hold the chair of anatomy and pathology in the Faculty of Medicine in Paris * Aim of offering an opportunity for students to observe what they might only see once in their careers. * Or potentially never, despite the dissection of a large number of corpses. * Within institutions such as medical schools. * Aim of illustrating a certain number of rare and extraordinary pathologies * Whereas most of the organs observed during dissections of corpses were healthy organs * At that time, a benchmark on the abnormal; whereas today, a benchmark is built on the normal. * **Truth as idealization**: * Imaginary Representation, extreme. * Importance for the clinician of being able to confront the image they have of an organ with the altered image. * "Even an observer with lynx eyes and an elephant's memory cannot fix these fugitive traits, if he does not engrave them as on bronze, in such a way as to be able to bring them to mind if necessary, and to compare them to similar facts" (Cruveilhier). * Precautions, almost obsessive, of anatomy textbook authors taken to ensure the fidelity of their figures. * In light of their knowledge. * Fidelity proceeding on the exercise of a reasoned judgment: * Judgment based on the selection of images or typical representations (or averages) that they have of the pathology. * Representations as a merger, synthesis of all possible varieties of pathologies on a single image. * Authors of atlases focusing on essentials, not hesitating to intervene on representations: * Example: exacerbated pathology (a kind of accumulation of pathologies) on images of a liver or a diseased heart. ### Scientific objectivity * In a context of truths from nature. * The aim of scientific objectivity is added to the artistic representation that preceded it. * "Scientific objectivity, based on imagery only appeared timidly in the mid-19th century, before developing thereafter with increasing intensity" (Daston and Galison). * Not initially aiming to replace "truth from nature", but rather to add to these representations. * Emphasis on the normal characteristics of the organism. * A new scientific vision = "blind" vision = not necessarily visible to the naked eye. * Devices that can measure what is invisible to the naked eye * Devices making it possible to consider a representation of these hidden structures, and not to make them visible through observation. * Example: spirometer, sphygmograph, automatic tracing of the pulse via ECG. ### Fidelity to observation * And not any more selection, choice. * From the German physiologist Otto Funke (1828-1879) and his research on hemoglobin. * The aim of achieving this fidelity, by seeking to come as close as possible to observations in his representations. * Sketches of observations under the microscope, very detailed, resembling almost photographs: effects of light. * Account of a reality that is blind, because it is infinitely small, revealing the underlying biological reality. ### The relationship between art and medical science * **In the past**: * Use of great artists * André Vésale used artists in the Renaissance * **From the mid-19th century onwards**: * **Rejection of art in science**: * Scientific knowledge made the artistic gaze superfluous. * Found in the introductory speech given by the professor of anatomy William Anderson (1842-1900). * English doctor, at the Medical and Physical Society of St Thomas's Hospital * The idea that medicine at the end of the 19th century can no longer be satisfied with employing the great artists of the time. * But must ultimately rely on its own objective representations. * The artist as a burden or even an obstacle to the development of knowledge. * The artistic gaze can mislead on the reality of pathology. * **Late 19th-early 20th century**: * **Questioning of mechanical objectivity and subjectivity**: * Trust in only mechanical objectivity gradually declines. * Awareness of the difficulty of representing realistically according to the ideal of objectivity = difficulties in objectively accounting for all the facts. * The limitations of the photographic plate * Though Koch was one of the first to tout photography as an asset for making the existence of microorganisms visible. * The plate can only capture a limited fraction of the preparation. * Only one focal plane visible due to its depth of field => the image is blurred at the edge. * The limitations of drawing done by scientists, such as Otto Funke. * Because drawing is always making a choice, that of emphasizing one aspect or another. ### Unattainable objectivity: should we prefer subjectivity? * **Scientist**: One of the inventors of cell theory. * **Quote**: "I am now one of the oldest professors of medicine: I have taught this science for more than thirty years, and I would say that during these thirty years, I have honestly worked to rid myself as much as possible of my subjective being and to guide myself ever further into the waters of objectivity. I must nevertheless admit that it has not been possible for me to become totally objective. I must admit, that year after year, I am forced to recognize that where I thought myself totally objective, I have continued to cling to largely subjective points of view." * **Crisis of trust in mechanical objectivity**: * Form of subjectivity that cannot be detached from. * The idea of taking into account this subjectivity of the scientific gaze. * A non-layperson's perspective. * The knowledge of the physician is not universal, but an acquisition on a case-by-case basis. * **Found in many scientists in the early 20th century**: * The idea that subjective judgment is always present and also necessary in science. ### A "blind" objectivity: Scientific objectivity as reasoned judgment in the 20th century * ***Trained eye*** * An eye capable of perceiving characteristics invisible to the layman. * The ability to interpret the signal obtained by mechanical objectivity * By Gibbs, in their atlas * The need to have a trained eye to recognize stones among themselves. *"The polishing of the surface had such an influence on the reflectivity [...] that "the novice was often induced to make gross errors. The color, too, lent itself to "remarkable misinterpretations" before the neophyte acquired a "highly experienced eye"*** * **Expert can train**: unlike the wise person. * **Expert**, unlike the machine, is expected to learn how to read, interpret, and bring out salient and significant structures. * Super technician, far more than a physician. * Because the objectivity obtained through mechanization must be coupled with a trained expert's eye to be able to identify the specificities of the observed artifacts. * Example: Knowing how to correctly interpret an electroencephalogram requires knowing how to identify the specificities of such and such a pathology in it. * **The figure of the expert**: * The image is still present today. * Certain medical specialties giving this impression of hyper experienced technicians who are able to interpret data from an objective, mechanical source. * **The electroencephalogram was more about empirical art than exact science" (Gibbs and Gibbs)** * Skills required to read an electroencephalogram compared to those required to read a language with an unknown alphabet. * **An empirical art**: * Empirical art allowing to isolate the normal part of the train of waves in the electroencephalogram. * Unlike automatic methods constrained to examining each fragment scrupulously. * Still true today: AI is not able to replace the trained eye of the doctor. * Empirical art allowing very quickly to identify the abnormal portions of the train of signal. * Identification thanks to the trained eye. * Where no automaton is capable of isolating these elements or seeing what is pathological about them. ### A new scientific objectivity: objectivity as reasoned judgment, that of biomedicine * **A new approach to mechanical objectivity in reading**: * The need to be able to propose a reasoned judgment = going beyond the simple reading of a mechanical device. * The need to be able to reveal what is essential in the image. * Objectivity alone, like photography, cannot do this. * **An unreliable non-infaillible reading**: * Fallibility of the judgment made. * **A focused gaze**: * The trained eye of the doctor will draw attention to certain points of an image rather than others. * Choice of angles, perspective based on an image obtained by mechanical objectivity. * The experienced doctor knows how to focus on the most appropriate technique. * **A redefined realism that differs from naturalism**: * Certain traits are going to be magnified, amplified to highlight contrasts or differences. * Example of theoretical montages made with overlays in the "Atlas Radiographique du Cerveau Humain" by Schwarz and Golthamer of 1965. * Images obtained through radiographs are made more realistic by supplemental details. * Therefore, against purely mechanical objectivity. * The aim of achieving a truth that is "truer than nature" by accounting for a certain reality that makes sense in relation to what one is trying to understand. ### Objectivity in a clinical perspective: what objectivity should define health and disease? #### Clinical approach * **Question of objectivity**: The question of what qualifies the objectivity of a doctor's opinion given to a patient concerning their health and illness. * **Reading of clinical results**: * Interpretation by the caregiver, in light of their knowledge, of the results. * Presentation by the caregiver to the patient of their therapeutic approach: diagnosis and treatment. * The question of what kind of objectivity the doctor adopts when they propose to intervene therapeutically. * **Confrontation of two subjectivities**: * That of the caregiver * That of the patient. * **Evaluative dimension**: * The doctor makes a judgment of value when they choose one treatment over another, deduced from the interpretation of the results. * Choice, among several possible alternatives, of the action that will bring the most benefit. * Therefore, not a mechanical objectivity because it is an adaptation to the patient´s specific case.. * **Expertise**: * The protocolisation of the therapeutic approach of modern medicine. * The doctor's opinion is not personal, although it can be coordinated with the patient according to the possible alternatives. * Protocols making possible a certain form of objective diagnosis * Reduction of the doctor´s subjectivity, erasing the patriarchal vision of the doctor. #### The question of clinical judgment * Judgment, not personal, defined as the action that allows to make a judgment about someone or something. * The question of knowing on what this judgment rests if it is not based on the doctor´s personal opinion (= by what objectivity should health and illness be defined). * Consensus or convention or reasoned opinion or deliberation. #### Consensus * **Originating in physiology**: * A term used to highlight the interdependence of organs in the performance of vital functions. * The idea of harmony. * **Brought back by sociology**: * Since the 19th century. * Integration and interpretation of all aspects of social reality in a whole. * **Common definition**: * Agreement of several people, or several texts, in a given field. * A term of Latin origin meaning "agreement". * **Social consensus**: * The idea that it is possible to obtain an agreement between people in society so that they function together. * Metaphor between organ function and the functioning of a system. * **Scientific consensus'**: * Any judgment or collective position and opinion of the scientific community in a given field of study. * Implies a general agreement even if not necessarily unanimous. * Example: plate tectonics, the spherical shape of the Earth * **Consensus in medicine**: * Public declaration on a particular aspect of medical knowledge at the time the declaration is made. * On which a representative group of experts agree as being grounded in evidence and reflecting the state of science at that particular time. * Factors of objectivity. * To differentiate from medical directives: * Given by governing bodies, with criteria that vary, even if they are sometimes less demanding due to political decisions. * Not simply an expert opinion, but draws on objectivity that is always becoming more profound. * Scientific studies, multidisciplinary approaches. * Medical consensus always underlying formalized protocols by general practitioners. * Rare in medicine. #### Factors contributing to the objectivity of medical consensus * **Validity of nosological proposition**: * The quality of resemblance between what the proposition states and the cases identified as having the criteria of the proposition. * Example of the state of death: cessation of all brain activity, even with a heartbeat. * **Basis on which the evidence rests**: * More or less verified bases. * The more the bases are verified, the stronger the evidence is. * **Expected results': * A proposition will be considered as likely to gain wider consensus if it brings results. * For example, if its application is likely to produce effects. * Example: preventive vaccination leads to an improvement in group immunity. * **Reliability / reproducibility**: * The fact that the application of the criteria that reliability / reproducibility defines can be used without failure over a certain period of time. * **Validity**: * Proposition must be valid from a scientific point of view. * Realism without defrauding. * **Clinical applicability**: * Match between therapeutic possibility and normative expectations of society. * Example: a therapeutically effective medicine that is not accepted by doctors because it is too expensive and therefore not accessible to everyone. * **Clinical flexibility**: * Not the only option given. * The existence of diverse protocols, requiring no excessive expertise. * Example: different approaches to the management of post-traumatic mental disorders, with actions on immediate symptoms and actions of psychological work in the longer term to address the cause of the ailment. * **Clarity**: * Proposition clearly stated. * A protocol must be easily understood and interpreted. * Even more so in a multidisciplinary environment. * **Likely duration of validity**: * The opinion on when the protocol will need to be revised. * Because constantly revising it leads to a loss of objectivity. * Because knowledge evolves, and so do protocols. * **Presence of existing studies**: * The need to have clinical studies to formulate the consensus. #### Convention * **Common definition**: * What is agreed to think or do in a given field. * What is accepted by usage. * What is customary in an environment or society. * **Definition in medicine**: * A practice that is generally accepted by doctors when they meet, especially to reach a scientific consensus. * Habitually functioning: the convention comes before the consensus. * Convention that can result from a widespread practice, but without being based on clinical studies providing evidence. * Therefore, less objectivity than a consensus. * **Relying on a norm**: * Norm = a criterion or principle that governs behavior, or to which we refer to make a judgment of value. * The objectivity behind a convention is often much weaker and often refers to a value judgment by the norm. * Example: the fact that an ailment implies a biological malfunction is not something necessary, but rather useful for acting medically on the illness. * The norm refers to the possibility of acting according to a convention. #### Reasoned opinion * **Definition**: * An opinion that rests on a thought process that is the fruit of reasoning. * Not simply moral or personal opinion. * Reasoning based on a body of biological and medical knowledge * **Question raised**: * The question of whether a reasoned opinion can answer or not to a singular request. #### Reasoning * **Hypothetico-deductive reasoning**: * The process of recognition linked to a similarity between models of illness (body of knowledge) and a singular clinical picture (patient's symptoms). * Seeing if the clinical picture confirms one's starting hypothesis or not. * Prescribing additional examinations to test one's diagnostic hypothesis * **Probabilistic reasoning**: * Almost instantaneous reasoning by the experienced physician. * Reasoning close to, but distinct from the experimental method of C. Bernard who aims to advance scientific knowledge. * An innovative approach by C. Bernard, against a comparative approach (tables and corpus) by the physician. * The calculation of the probability of illness. * With the knowledge of the frequency of diseases. * By using Bayes' theorem. * Heavy reasoning. * IT techniques and characteristics of the populations that must be known. * Not frequently carried out in a general medical practice. * Example: the frequency of a genetic pathology X in the hip is higher among people of Scottish origin. * **Application of algorithms with branching**: * Branching allowing the successive elimination of hypotheses. * The patient's data entered into a computer system, which provides the probabilities of such and such a disease. * Automation * Artificial intelligence * Developing more and more in medical practice. * Example: radiology * Often too rigid. #### Abductive inference = the mental process of reasoned opinion * **Concept of the second half of the 19th century**: * Described by the philosopher Charles Sanders Pierce. * **Aim**: * To unify the clinical diagnostic reasoning and the hypothetico-deductive approach of Claude Bernard. * Starting point: descriptive data, observed facts. * Endpoint: a hypothesis that agrees with the initial data. * **Not specific to medical reasoning**: * Example: a mobile phone battery and inference about the potential remaining autonomy. * Whereas the hypothesis of a faulty charge indicator for the phone is rejected. * One and the same intellectual reasoned process, including steps without realizing it: * Hypothesis, testing, acceptance of the explanatory hypothesis * The process is carried out almost instantaneously by the doctor, without their being aware of these different steps. * The same process found in detectives. * Example: in Sherlock Holmes investigations. * **Diagnosis conceived as an explanation of symptoms**: * Explanation that must be considered as plausible and significantly better than other possible explanations. * **Difficulty**: the absence of sufficient background data provided to the practitioner. * **Internal dialogue important in medical practice for questioning the foundation of reasoning**: * In order to be able to break down the reasoning that is usually carried out almost instantly and with no conscious awareness. * The justification of abductive reasoning can lead to a dialogue, in addition to the result. * Questions which indicate, for any possible diagnosis that has been made, whether it is false. * A set of questions to which anyone who makes a diagnosis must be prepared to respond. * Example with Semmelweis who laid the foundations of asepsis in medicine (in the middle of the 19th century). * Many hypotheses had been made at the time to understand the spread of puerperal fever in maternity hospitals, resulting in the deaths of mothers and even children. * In his reasoning, Semmelweis makes an abductive inference allowing him to understand the transmission of the illness: students delivering babies were not washing their hands, whereas they had just performed dissections. #### Example taken from the *Dictionary of Medical Thought* by Alain-Charles Masquelet * **Clinical situation**: * Patient with liver disease and hepatomegaly = abnormal increase in liver size. * **Hypotheses formulated by the doctor**: * Liver congestion * Liver infection * Increase in liver size without infection * Neoplasia = abnormal cell growth (cancer). * **Testing the hypotheses**: * Each hypothesis is tested by looking for the symptoms and specific signs for each. * In the absence of signs, only the hypothesis of neoplasia is retained. * **Difficulty**: * The lack of hypotheses in the list of possible causes of hepatomegaly from the start: the practitioner may be unaware of certain causes. * Or, hypotheses may have been rejected too quickly. * The practitioner may have wrongly thought that certain hypotheses did not account for clinical manifestations. * The practitioner may have wrongly thought that the retained hypothesis explained the clinical manifestations. * The diagnostic conclusion is wrongly considered to be the best hypothesis. * However, the true diagnosis is a pancreatic cancer that caused the hepatomegaly => diagnostic error. * Either due to insufficient knowledge. * Or due to a lack of evidence. #### Deliberation * **Definition**: * The action of thinking, deliberating. * **Alone**: deliberation with oneself, weighing the pros and cons of each hypothesis internally. * **With others** * A decision emerging from an examination. * A metonymic acceptation. * Current meaning: collective discussion leading to a decision. * **Aim in medicine**: * To avoid applying conventions systematically. * By confronting points of view: debates. * Confronting the different reasons that may justify a decision. * To reach a decision. * Even if deliberation does not necessarily involve a decision. * Deliberation can unblock situations without necessarily leading to a decision. * Dissociation between the deliberation step and the decision step. * Deliberation more often has an aim of ethical reflection than an aim of seeking truth. * To put everything on the table, so as not to forget anything. * Example: collegiate procedures in the face of cancer diagnoses. * Example: Deliberation of the jury in a Court of Assizes regarding the guilt of an accused. * A debate that can take place before a reasoned opinion in order to prevent the proposed hypotheses from being too restrictive. * **Question of objectivity**: * To reason explicitly. * Because abductive reasoning is often instantaneous, hence the possibility of bias. * Hence the idea of revealing a priori. * Hence the idea of bringing to the fore the diversity of singular positions, of personal values. #### Conclusion: Objectivity in the clinic * **Not unique**: * Objectivity has a long and multifaceted conceptual history, showing its different forms of expression. * **Taking several forms**: * In the diagnostic approach. * In the therapeutic approach. * Plurality that is not relativism * The idea that truth would be specific to each individual. * *"It depends on the doctors." * A plurality that is not subjectivism. * The fact that each person would have their own truth. * **Aim of truth**: * Truth as a match between reality and the man who thinks it.