Bacteriological Revolution In The 19th Century
Was there a bacteriological revolution in the 19th century?
Introduction
The changes in medicine, and particularly epidemiology, that took place during the 19th century, concentrated in the latter half of the century, are often referred to as a revolution by medical historians. Here I consider whether these changes exemplify a Kuhnian revolution. To do this I first outline the characteristics of a Kuhnian revolution, I will then outline the changes in medical practice over the 19th century. I will then consider the change in epidemiology in light of Kuhn’s ideas and then an altered Kuhnian view put across by Gillies. Concluding that the proposed bacteriological revolution does not fit that of a characteristic Kuhnian revolution.
Scientific …show more content…
Change according to Kuhn
Kuhn did not specifically use any examples from medicine when defining a scientific revolution though his ideas have, in subsequent years, been applied to medical practice (Gillies, 2005). According to Kuhn scientific history is made up of a series of non-compatible paradigms which in part or entirely replace their predecessor via revolution (Kuhn, 1962), due to the incompatibility there is not there is not cumulative growth of knowledge between paradigms. Kuhn also talks of a pre-paradigmic time where there was no dominant theory but instead a number of competing schools of thought which becomes a paradigm when one school of thought becomes dominant (Kuhn, 1962). Within paradigms “normal science” which is problem solving within the constraints of the paradigm occurs, this science, unlike interparadigmic science can be cumulative (Kuhn, 1962). The catalyst causing the change from this normal science to a revolution is a number of anomalies showing that the paradigm is no longer fit for purpose (Kuhn, 1962). One example Kuhn gives of this, is the change from a geocentric idea of the solar system to the Copernican heliocentric solar system. The anomalies being observations of the movements of celestial objects which could not be explained in the geocentric model. The geocentric model was altered in an attempt to account for these discrepancies however as the weight of evidence and anomalies grew popular scientific opinion changed from a geocentric view of the solar system to a heliocentric one (Kuhn, 1962). In what follows I will assess whether this sort of shift occurred in medicine in the 19th century.
Epidemiology in the 19th Century
At the beginning of this time period the miasma and contagion theories were the most popular suggested causes of disease. The miasma theory stated that disease were caused by “bad airs” or smells (Kokayeff, 2013). The reasoning for the miasma theory came from the fact that many smells, such as rotting flesh, are commonly associated with disease and are unpleasant to most people, our disdain for them being caused by the fact that they are dangerous (Kokayeff, , 2013). The contagion theory of disease claimed that is that diseases could be passed from one person to another, producing the same disease as that which the disease transmitter had (Gillies, 2005). Bacteria had been know about for centuries however Pasteur was one of the forerunners of linking bacteria and disease in the mid nineteenth century (Worboys, 2007). Bacteria, towards the end of the 19th century, became an accepted causal agent of disease as bacteria necessary (as opposed to simply sufficient) for a certain disease were being isolated. Many diseases which were previously thought of as being caused by more outdated hypothesis were then reclassified as having a bacteriological cause (Worboys, 2007).
Kuhn and Causation in Medicine
Causation in epidemiology can be seen as markedly different to causation in the natural sciences. The cause of a particular disease is very often seen as particular to that ailment; throughout medical history it has been recognised that different diseases are caused by different things; there is not one single disease agent. Contrast this with physics, where there are thought to be laws which govern all systems in the universe and linked causal mechanisms. This means that if one of these is questioned or the scheme of them all is questioned there must be an upheaval in order to allow for this. However the cause of a single disease can be found to be something else and this not cause an upheaval in the same way. According to Kuhn paradigms are non-compatible and one cannot hold that both are true at the same time. This is not what happened during the so called bacteriological revolution, people were able to, and did hold that some diseases were caused by bacteria, others by miasmas and others by contagions (Gillies, 2005). So clearly the Kuhnian model of science cannot simply be mapped onto the case of medicine.
Gillies’ Version of Kuhnian Theory
Gillies recognised this asymmetry between natural sciences and epidemiology so puts forward a way of applying Kuhnian ideas to medicine in a way that accounts for the composite nature of epidemiology. However I show that this is not sufficient to capture the intricacies of medical theory change.
According to him we should understand a paradigm in medicine as being:
i) The general scheme of the classification of diseases and disease explanations ii)”Local paradigms” applying to certain classes of diseases (Gillies, 2005)
This formulation appears to preserve Kuhn’s classification of paradigms however what should be classed as a revolution in this formalisation is much less clear. Take (i) above should we allow for there to be a revolution in epidemiology whenever a new disease agent is discovered? This seems not to be the case. Take for example the case of the discovery that prions were a disease agent during the 1980s. Prions are proteins which are able to mimic bacteria and viruses thereby causing disease particularly in the nervous system (Colby and Prusiner, 2011). In many ways this is a typical Kuhnian case and shares a number of similarities with the bacteriological case. This was a completely new type of disease agent unlike any theories that were accepted at the time and when the theory was first suggested it was “met with great resistance” (Colby and Prusiner, 2011) though it is now part of the accepted body of medical knowledge. However it is not the case that the discovery of this new disease agent can be said to have resulted in a large scale medical change of any kind instead it was simply accepted as a possible disease agent ((Colby and Prusiner, 2011).
It, perhaps, could be said that the discovery of prions resulted in a kind of “mini-revolution” (Gillies, 2005) as the diseases which were once classified as being caused by something else or had no known causal agent were reclassified, and perhaps this is how we should understand revolutions in medicine. This is the sort of thing Gillies is referring to in (ii). In particular Gillies references the discovery that peptic stomach ulcers. These had in the past been thought to have been caused by increased acid due to stress were then discovered to be caused by bacteria (Gillies, 2005). The revolution in this example follows the shape of that of a Kuhnian revolution, the two paradigms are distinct from each other and are incompatible so can justifiably be referred to as a mini Kuhnian revolution.
Multiple Causality of Diseases
However this can only be guaranteed for diseases with a singular necessary and sufficient cause.
If it is the case that a disease has multiple mutually sufficient causal mechanisms it again seems as if the Kuhnian idea of paradigms breaks down here, as it did for the case of epidemiology in a macro sense. Consider lung cancer, there is no one necessary and sufficient cause for lung cancer instead there are multiple causes which interact with each other such as smoking, work environment, processed meat consumption etc. (Rotham and Greenland, 2005) In this circumstance if a new cause of cancer is discovered, as it seems to in some newspaper every week, it would be difficult to characterise the miniscule local oncological paradigm changes as anything other than normal science. Hence even the idea of Kuhnian revolution when applied to a local disease paradigm is not always applicable. Applying this to the case of the suggested bacteriological revolution, before bacteria was a known pathogen diseases were not thought of as having singular necessary and sufficient causes; multiple factors were acknowledged to be the cause of a certain disease. For example accepted causes of cholera included rotting food, anger and “cold fruits” such as melons or cucumbers (Marsh). Hence the epidemiological landscape even for specific diseases of the time doesn’t seem to fit with Kuhnian paradigms. The most that can be said is that each disease went from a pre-paradigmic stage to a paradigm as the causal agent was identified as being a particular bacterium, if these bacteria were seen as a single necessary and sufficient cause. This was the case in many but not all of the reclassifications of disease that took place in the latter half of the nineteenth century (Worboys,
2007).
Conclusion
The notion of a Kuhnian paradigm-revolution system does not map very well onto the study of disease causation. The most Kuhnian thing we can say is that some areas of medicine can experience revolutions on a micro scale, if that area of medicine is dictated by singular necessary and sufficient causes. So macro changes in medicine such as the proposed bacteriological revolution would have to be understood as a number (picked reasonably arbitrarily) of these mini-revolutions occurring in the areas of medicine where the causal agent is understood to be singular, necessary and sufficient in an arbitrarily decided time frame. In the case of the suggested bacteriological revolution, it does not seem to be the case that earlier in the nineteenth century even singular diseases were in a paradigmic state. One could still say with the reworked definition of a Kuhn-like revolution that we perhaps went from a pre-paradigmic stage to a paradigmic stage. This however this conception is clearly very different to a Kuhnian revolution realised in the natural sciences and conceivably should not be able to identify itself with a Kuhnian revolution.
Introduction
The changes in medicine, and particularly epidemiology, that took place during the 19th century, concentrated in the latter half of the century, are often referred to as a revolution by medical historians. Here I consider whether these changes exemplify a Kuhnian revolution. To do this I first outline the characteristics of a Kuhnian revolution, I will then outline the changes in medical practice over the 19th century. I will then consider the change in epidemiology in light of Kuhn’s ideas and then an altered Kuhnian view put across by Gillies. Concluding that the proposed bacteriological revolution does not fit that of a characteristic Kuhnian revolution.
Scientific …show more content…
Change according to Kuhn
Kuhn did not specifically use any examples from medicine when defining a scientific revolution though his ideas have, in subsequent years, been applied to medical practice (Gillies, 2005). According to Kuhn scientific history is made up of a series of non-compatible paradigms which in part or entirely replace their predecessor via revolution (Kuhn, 1962), due to the incompatibility there is not there is not cumulative growth of knowledge between paradigms. Kuhn also talks of a pre-paradigmic time where there was no dominant theory but instead a number of competing schools of thought which becomes a paradigm when one school of thought becomes dominant (Kuhn, 1962). Within paradigms “normal science” which is problem solving within the constraints of the paradigm occurs, this science, unlike interparadigmic science can be cumulative (Kuhn, 1962). The catalyst causing the change from this normal science to a revolution is a number of anomalies showing that the paradigm is no longer fit for purpose (Kuhn, 1962). One example Kuhn gives of this, is the change from a geocentric idea of the solar system to the Copernican heliocentric solar system. The anomalies being observations of the movements of celestial objects which could not be explained in the geocentric model. The geocentric model was altered in an attempt to account for these discrepancies however as the weight of evidence and anomalies grew popular scientific opinion changed from a geocentric view of the solar system to a heliocentric one (Kuhn, 1962). In what follows I will assess whether this sort of shift occurred in medicine in the 19th century.
Epidemiology in the 19th Century
At the beginning of this time period the miasma and contagion theories were the most popular suggested causes of disease. The miasma theory stated that disease were caused by “bad airs” or smells (Kokayeff, 2013). The reasoning for the miasma theory came from the fact that many smells, such as rotting flesh, are commonly associated with disease and are unpleasant to most people, our disdain for them being caused by the fact that they are dangerous (Kokayeff, , 2013). The contagion theory of disease claimed that is that diseases could be passed from one person to another, producing the same disease as that which the disease transmitter had (Gillies, 2005). Bacteria had been know about for centuries however Pasteur was one of the forerunners of linking bacteria and disease in the mid nineteenth century (Worboys, 2007). Bacteria, towards the end of the 19th century, became an accepted causal agent of disease as bacteria necessary (as opposed to simply sufficient) for a certain disease were being isolated. Many diseases which were previously thought of as being caused by more outdated hypothesis were then reclassified as having a bacteriological cause (Worboys, 2007).
Kuhn and Causation in Medicine
Causation in epidemiology can be seen as markedly different to causation in the natural sciences. The cause of a particular disease is very often seen as particular to that ailment; throughout medical history it has been recognised that different diseases are caused by different things; there is not one single disease agent. Contrast this with physics, where there are thought to be laws which govern all systems in the universe and linked causal mechanisms. This means that if one of these is questioned or the scheme of them all is questioned there must be an upheaval in order to allow for this. However the cause of a single disease can be found to be something else and this not cause an upheaval in the same way. According to Kuhn paradigms are non-compatible and one cannot hold that both are true at the same time. This is not what happened during the so called bacteriological revolution, people were able to, and did hold that some diseases were caused by bacteria, others by miasmas and others by contagions (Gillies, 2005). So clearly the Kuhnian model of science cannot simply be mapped onto the case of medicine.
Gillies’ Version of Kuhnian Theory
Gillies recognised this asymmetry between natural sciences and epidemiology so puts forward a way of applying Kuhnian ideas to medicine in a way that accounts for the composite nature of epidemiology. However I show that this is not sufficient to capture the intricacies of medical theory change.
According to him we should understand a paradigm in medicine as being:
i) The general scheme of the classification of diseases and disease explanations ii)”Local paradigms” applying to certain classes of diseases (Gillies, 2005)
This formulation appears to preserve Kuhn’s classification of paradigms however what should be classed as a revolution in this formalisation is much less clear. Take (i) above should we allow for there to be a revolution in epidemiology whenever a new disease agent is discovered? This seems not to be the case. Take for example the case of the discovery that prions were a disease agent during the 1980s. Prions are proteins which are able to mimic bacteria and viruses thereby causing disease particularly in the nervous system (Colby and Prusiner, 2011). In many ways this is a typical Kuhnian case and shares a number of similarities with the bacteriological case. This was a completely new type of disease agent unlike any theories that were accepted at the time and when the theory was first suggested it was “met with great resistance” (Colby and Prusiner, 2011) though it is now part of the accepted body of medical knowledge. However it is not the case that the discovery of this new disease agent can be said to have resulted in a large scale medical change of any kind instead it was simply accepted as a possible disease agent ((Colby and Prusiner, 2011).
It, perhaps, could be said that the discovery of prions resulted in a kind of “mini-revolution” (Gillies, 2005) as the diseases which were once classified as being caused by something else or had no known causal agent were reclassified, and perhaps this is how we should understand revolutions in medicine. This is the sort of thing Gillies is referring to in (ii). In particular Gillies references the discovery that peptic stomach ulcers. These had in the past been thought to have been caused by increased acid due to stress were then discovered to be caused by bacteria (Gillies, 2005). The revolution in this example follows the shape of that of a Kuhnian revolution, the two paradigms are distinct from each other and are incompatible so can justifiably be referred to as a mini Kuhnian revolution.
Multiple Causality of Diseases
However this can only be guaranteed for diseases with a singular necessary and sufficient cause.
If it is the case that a disease has multiple mutually sufficient causal mechanisms it again seems as if the Kuhnian idea of paradigms breaks down here, as it did for the case of epidemiology in a macro sense. Consider lung cancer, there is no one necessary and sufficient cause for lung cancer instead there are multiple causes which interact with each other such as smoking, work environment, processed meat consumption etc. (Rotham and Greenland, 2005) In this circumstance if a new cause of cancer is discovered, as it seems to in some newspaper every week, it would be difficult to characterise the miniscule local oncological paradigm changes as anything other than normal science. Hence even the idea of Kuhnian revolution when applied to a local disease paradigm is not always applicable. Applying this to the case of the suggested bacteriological revolution, before bacteria was a known pathogen diseases were not thought of as having singular necessary and sufficient causes; multiple factors were acknowledged to be the cause of a certain disease. For example accepted causes of cholera included rotting food, anger and “cold fruits” such as melons or cucumbers (Marsh). Hence the epidemiological landscape even for specific diseases of the time doesn’t seem to fit with Kuhnian paradigms. The most that can be said is that each disease went from a pre-paradigmic stage to a paradigm as the causal agent was identified as being a particular bacterium, if these bacteria were seen as a single necessary and sufficient cause. This was the case in many but not all of the reclassifications of disease that took place in the latter half of the nineteenth century (Worboys,
2007).
Conclusion
The notion of a Kuhnian paradigm-revolution system does not map very well onto the study of disease causation. The most Kuhnian thing we can say is that some areas of medicine can experience revolutions on a micro scale, if that area of medicine is dictated by singular necessary and sufficient causes. So macro changes in medicine such as the proposed bacteriological revolution would have to be understood as a number (picked reasonably arbitrarily) of these mini-revolutions occurring in the areas of medicine where the causal agent is understood to be singular, necessary and sufficient in an arbitrarily decided time frame. In the case of the suggested bacteriological revolution, it does not seem to be the case that earlier in the nineteenth century even singular diseases were in a paradigmic state. One could still say with the reworked definition of a Kuhn-like revolution that we perhaps went from a pre-paradigmic stage to a paradigmic stage. This however this conception is clearly very different to a Kuhnian revolution realised in the natural sciences and conceivably should not be able to identify itself with a Kuhnian revolution.