A topic in Learners' conceptions and thinking
There are many ideas that have been mooted in the history of science (and, before science was formally recognised, 'natural philosophy') that are no longer used in scientific discourse today (phlogiston, caloric, the luminiferous ether….) Some of these ideas never got beyond being someone's pet suggestion, but some were at one time as widely accepted as the most well-established scientific ideas are today.
"There are plenty of ideas in science that have at one time been considered canonical, but have later been discredited and de-canonised; plenty of generalisations and law-like principles that have been later found to be approximations or have limited ranges of application (e.g., the central dogma of molecular biology…) and plenty of ideas that may have seemed heretical (e.g., jumping genes…) that have later entered the canon."
Taber, 2019: 93
There is a value in considering historical scientific ideas, in part because they help us understand a little about the path that was taken towards current scientific thinking. This might be valuable in avoiding the 'rhetoric of conclusions', where well-accepted ideas become so familiar that we come to take them for granted and ignore the ways in which such ideas often came to be accepted in the face of competing notions and mixed experimental evidence.
For the science educator there are added benefits. It reminds us that highly intelligent and well motivated scholars, without the value of the body of scientific discourse and evidence available today, might sensibly come to seriously entertain ideas that seem today ill-conceived, sometimes convoluted, and perhaps even foolish. That is useful for teachers to bear in mind when students fail to immediately understand the science they are taught and present with alternative conceptions that may seem illogical or fantastic to the teacher. Insight into the thinking of others can perhaps help us shift their thinking and so make us better teachers.
History and the nature of science
Paying attention to historical scientific ideas, both why they were eventually dropped, as well as why they were once favoured as explanations, is also very useful for teaching about the nature of science,
"If we are to adhere to a strict scientific attitude, then we need to adopt a humility about the current scientific canon. All scientific ideas, no matter how widely accepted, no matter how well supported by our current interpretations of broad bodies of evidence, need to be seen as somewhat provisional; as potentially revisable; as, in principle, open to reconsideration in the light of new evidence or of new ways of conceptualising the existing evidence. To think otherwise, would be scientistic arrogance."
Taber, 2019: 93
Read about teaching the nature of science
Current and Historical Scientific Concepts
I have argued that when considering people's conceptions of the natural world, it is useful to make the following discriminations: 1
- (i) everyday concepts vs. scientific concepts; and among the scientific concepts:
- (ii) historical (scientific) concepts vs. current (scientific) concepts; and among the current concepts:
- (iii) canonical (current scientific) concepts vs. mooted (current scientific) concepts.
The term 'canonical' is used to refer to concepts that are currently gene§rally accepted within the scientific community. 2
"…we might distinguish between concepts that are scientific and those that are not (the former being formed through the processes of science); and then also between those scientific concepts that are historical and those that are current. We should also make another discrimination, and not necessarily equate a current scientific concept with a canonical one."
Taber, 2019: 94
Everyday concepts here refers to the informal ideas that students often present with that are labelled as alternative conceptions, alternative conceptual frameworks, misconceptions, intuitive theories, and so forth. Some of these idea are in wide circulation as 'folk science'.
Read about alternative concepts
Not all current scientific ideas are canonical
When we refer to scientific ideas, scientific concepts, scientific knowledge, scientific theories, and so forth, this may give the impression we refer to ideas that are generally accepted among scientists. However, science is an ongoing process, so at any time there will be ideas being suggested and seriously debated by scientists which are not yet widely accepted, and may never become so. But these ideas are still 'scientific' as they derive form and have currency from the professional practices of the scientific community.
"There is a time lag between the proposal of a scientific concept, and its admission into the canon, and prior to that point it will not be known whether the concept will come to be seen as canonical. So, many concepts that are formed (i.e., invented) by scientists and that derive from the systematic, iterative processes of science (and so, in the usage here, are scientific concepts), never become canonical. In retrospect, we might judge these as historical, but whilst they are still current they remain candidates for being adopted by the community of scientists."
Taber, 2019: 94
An example from recent years concerns the causes of A.I.D.S. (acquired immune deficiency syndrome). It is not scientific consensus that the disease is caused by an infectious agent, a retrovirus called the human immunodeficiency virus (H.I.V.). However, before this was well-established, when A.I.D.S. was still a new disease, there was an alternative hypothesis that A.I.D.S was a condition triggered by an over-stressed immune system and within that framework it was suggested that H.I.V. was a relatively benign and ubiquitous virus which was present merely as a side effect,and so indicator, of the damaged immune system. Over time, as more studies were undertaken, and more research was completed offering increasing evidence of the role of H.I.V., the alterative view became less credible until it was eventually only held by a very small number of specialist scientists (and became considered a scientific 'heresy').
That is, once a concept is, through the consensus of a scientific community, rejected as flawed or simply unhelpful, then we can see it as no longer current.
Taber, 2019: 94-5
An example might be 'string theory' which has been very widely debated and explored, but remains speculative. In a century form now it may be scientific orthodoxy – or it might be an idea that is no longer part of scientific discourse, no longer referred to in research papers, or presented in the text books, but only discussed by historians of science!
"Current concepts that are not canonical are not necessarily those that will never be canonical, but rather a mixture of those that will become widely adopted, and those that will fall into disuse without ever having achieved canonical status. Which of these candidates will become promoted to canonical status is (and must be) an open question. It might be helpful to have a term then to distinguish these levels of currency – such as canonical concepts and mooted concepts."
Taber, 2019: 95
Not all historical scientific ideas were canonical
Most historical scientific ideas that are widely discussed today were at one time canonical – used widely by the scientists (or equivalent) of their day. However, there were other ideas which had currency once, but which never moved beyond being mooted to actually persuading the general community of scientists of their usefulness.3
"Historical, as well as current, scientific concepts either may, or may not, attain canonical status (although for understandable reasons it is mostly those historical concepts that were at one time canonical that are widely known today)."
Taber, 2019: 95
So we might consider scientific ideas – ideas which have, or have had, currency in scientific research communities to fall into one of the following cells
scientific concepts | mooted | canonical |
current | an idea suggested and used by some scientists today that has not (yet) been generally accepted | an idea that is generally accepted as useful in scientific practice by scientists today |
historical | an idea suggested and used by some scientists at an earlier time that has never been generally accepted | an idea that was generally accepted as useful in scientific practice by scientists at an earlier time |
Over time, then, the status of scientific concepts can change, being promoted to canonical status (blue arrow) , or being relegated from part of current scientific discourse (red arrows):
An example of an idea that was widely considered scientific at one time, but is no longer accepted, is that behind phrenology.
Work cited
- Taber, K. S. (2019). The Nature of the Chemical Concept: Constructing chemical knowledge in teaching and learning. Cambridge: Royal Society of Chemistry.
Notes
1 For present purposes, I am treating 'concept' and 'conception' and 'idea' as equivalent terms.
2 Strictly, there are at least two problems with the idea of canonical concepts (Taber, 2019):
- There is a vast diversity of scientists (with different specialisms and expertise) so we can never expect a 100% consensus between scientists
- Even when scientists agree that a principle or theory or model is currently;y canonical, there are likely to be variations is exactly how they understand it and its range of application.
These are real issues that become significant in some cases, but often we can still offer ideas that are accepted by nearly all scientists and understood similarly enough to be referred to as canonical.
3 We might tend to think that science concerns what is true (e.g., canonical scientific concepts are true, current mooted ideas have not yet been 'proved' true; historical ideas have now been found not to be true…), and some scientific ideas are developed as accounts of the way the world is. However, many scientific ideas are considered to be models, or partial accounts, or even simply useful as ways of thinking to generate potentially useful hypotheses.
