Showing posts with label Scientific Method. Show all posts
Showing posts with label Scientific Method. Show all posts
Sunday, October 7, 2007
Monday, May 28, 2007
Mind your scientific language
By Lawrence Krauss
Writing in the New Scientist
Also see: Letters in response to this article
IN DESCRIBING humankind's fascination with extra dimensions for The New York Times recently, I made the mistake of mentioning string theory and intelligent design on the same page. My purpose was not to claim they are similar. Quite the opposite. I wanted to describe how both science and religion sometimes provoke heated debates about features of the universe we cannot measure. While string theory has yet to make contact with the empirical universe, it is a legitimate part of science, even if it proves a failure, because its practitioners are ultimately aiming to produce falsifiable results. The proponents of intelligent design, on the other hand, do not seem to have this intent.
My choice of examples provoked a furious discussion on several physics blogs. The juxtaposition particularly irritated a number of string theorists who seem sensitive to any scepticism regarding the whole string enterprise. This was not my intent, although I have been sceptical of many claims and accomplishments by string theorists in the past 20 years.
But the online discussions raise an important issue at a time when science is under attack on a number of fronts - particularly in the US - by groups who wish to change what we teach as science to include concepts that are traditionally the domain of theology.
I want to state up front that the string enterprise has produced a very impressive body of theoretical work and has been pushed forward by many talented and hard-working scientists. However, I believe that what we normally call string theory is not what most scientists would call a theory in the traditional scientific sense.
A scientific theory is a logically coherent and predictive system that has been tested against experiment or observation. It explains observable phenomena and makes falsifiable predictions about them.
Instead, the string enterprise (as one might choose to call it) is a broad set of mathematical concepts which have yet to be incorporated into a rigid theoretical structure that makes precise predictions - unlike the electroweak theory, for example, which makes predictions about particle physics. Nor does it make specific falsifiable assertions about observable phenomena, as evolutionary theory does in biology.
The string enterprise is not the only culprit. Another example of incorrect use of the term "theory" arises in cosmology, where scientists commonly speak of inflationary theory to describe the hypothesised growth of the universe soon after it began. Inflation is not so much a theory as a paradigm, a generally accepted perspective that is not associated with any particularly compelling mathematical model at this point.
The label "string theory" is actually an anachronism. The mathematics of the relativistic quantum mechanics of one-dimensional string-like objects was so named to distinguish it from that of point particles. The former was created in an attempt to circumvent various apparent mathematical infinities that beset the latter, called quantum field theory.
Maintaining this semantic distinction is not merely contentious nitpicking. A key part of the argument made by those who wish to introduce religion into science classes is that evolution is "just a theory". By "theory" these individuals are referring to the common lay usage of the word, meaning a hunch or a guess, and not the more restrictive sense in which the term is normally discussed in science. Because most members of the general public are not familiar with this distinction, the claim has resonated in the popular consciousness.
“The string enterprise has not produced anything that rises to the level of theory”
This causes problems. When debating the nature of science with advocates of intelligent design, I am frequently confronted with the claim that string theory is no more scientific than intelligent design. While I am satisfied that this is not the case, the fact that we probably use the term "theory" inappropriately in this case doesn't help quash the confusion.
Eugenie Scott of the National Center for Science Education, a US organisation that defends the teaching of evolution in schools, has argued that we should train ourselves to not use the term "believe" in a scientific context because it blurs the distinction between science and religion. My argument is the same. String theory is better thought of as a hypothesis or paradigm - a working framework upon which to develop a theory.
Of course there are those who will be offended by my suggestion that we should make it clear that the string enterprise has not produced anything that yet rises to the level of theory in the sense that scientists usually use this term. To them, I would argue that we can save ourselves grief down the line if we more precisely and more accurately represent to the public what we are doing, independently of how exciting those activities may seem to the participants.
Lawrence Krauss is Ambrose Swasey Professor of Physics at Case Western Reserve University, Cleveland, Ohio. His latest book is Hiding in the Mirror (Viking, 2005)
From issue 2528 of New Scientist magazine, 03 December 2005, page 23
Writing in the New Scientist
Also see: Letters in response to this article
IN DESCRIBING humankind's fascination with extra dimensions for The New York Times recently, I made the mistake of mentioning string theory and intelligent design on the same page. My purpose was not to claim they are similar. Quite the opposite. I wanted to describe how both science and religion sometimes provoke heated debates about features of the universe we cannot measure. While string theory has yet to make contact with the empirical universe, it is a legitimate part of science, even if it proves a failure, because its practitioners are ultimately aiming to produce falsifiable results. The proponents of intelligent design, on the other hand, do not seem to have this intent.
My choice of examples provoked a furious discussion on several physics blogs. The juxtaposition particularly irritated a number of string theorists who seem sensitive to any scepticism regarding the whole string enterprise. This was not my intent, although I have been sceptical of many claims and accomplishments by string theorists in the past 20 years.
But the online discussions raise an important issue at a time when science is under attack on a number of fronts - particularly in the US - by groups who wish to change what we teach as science to include concepts that are traditionally the domain of theology.
I want to state up front that the string enterprise has produced a very impressive body of theoretical work and has been pushed forward by many talented and hard-working scientists. However, I believe that what we normally call string theory is not what most scientists would call a theory in the traditional scientific sense.
A scientific theory is a logically coherent and predictive system that has been tested against experiment or observation. It explains observable phenomena and makes falsifiable predictions about them.
Instead, the string enterprise (as one might choose to call it) is a broad set of mathematical concepts which have yet to be incorporated into a rigid theoretical structure that makes precise predictions - unlike the electroweak theory, for example, which makes predictions about particle physics. Nor does it make specific falsifiable assertions about observable phenomena, as evolutionary theory does in biology.
The string enterprise is not the only culprit. Another example of incorrect use of the term "theory" arises in cosmology, where scientists commonly speak of inflationary theory to describe the hypothesised growth of the universe soon after it began. Inflation is not so much a theory as a paradigm, a generally accepted perspective that is not associated with any particularly compelling mathematical model at this point.
The label "string theory" is actually an anachronism. The mathematics of the relativistic quantum mechanics of one-dimensional string-like objects was so named to distinguish it from that of point particles. The former was created in an attempt to circumvent various apparent mathematical infinities that beset the latter, called quantum field theory.
Maintaining this semantic distinction is not merely contentious nitpicking. A key part of the argument made by those who wish to introduce religion into science classes is that evolution is "just a theory". By "theory" these individuals are referring to the common lay usage of the word, meaning a hunch or a guess, and not the more restrictive sense in which the term is normally discussed in science. Because most members of the general public are not familiar with this distinction, the claim has resonated in the popular consciousness.
“The string enterprise has not produced anything that rises to the level of theory”
This causes problems. When debating the nature of science with advocates of intelligent design, I am frequently confronted with the claim that string theory is no more scientific than intelligent design. While I am satisfied that this is not the case, the fact that we probably use the term "theory" inappropriately in this case doesn't help quash the confusion.
Eugenie Scott of the National Center for Science Education, a US organisation that defends the teaching of evolution in schools, has argued that we should train ourselves to not use the term "believe" in a scientific context because it blurs the distinction between science and religion. My argument is the same. String theory is better thought of as a hypothesis or paradigm - a working framework upon which to develop a theory.
Of course there are those who will be offended by my suggestion that we should make it clear that the string enterprise has not produced anything that yet rises to the level of theory in the sense that scientists usually use this term. To them, I would argue that we can save ourselves grief down the line if we more precisely and more accurately represent to the public what we are doing, independently of how exciting those activities may seem to the participants.
Lawrence Krauss is Ambrose Swasey Professor of Physics at Case Western Reserve University, Cleveland, Ohio. His latest book is Hiding in the Mirror (Viking, 2005)
From issue 2528 of New Scientist magazine, 03 December 2005, page 23
What's the difference between a Theory and a Hypothesis?
From the letters page of New Scientist
See: Original Article
Lawrence Krauss is quite right that we need to be much clearer about the role of falsifiability in making a theory "scientific" (3 December, p 23). Despite taking mostly science subjects at school and having intelligent, motivated teachers, I reached the end of my secondary education without the concept having been mentioned once.
However, I'm not sure whether Krauss's attempt to clarify the word "theory" will do the trick. "Theory" is used both in normal speech and in science to refer to all varieties of idea, from wild speculation to well-tested systems. Krauss mentions falsifiable theories (such as Newton's theory of gravity), unfalsifiable theories that are at least aiming to be falsifiable (such as string theory) and theories which do not aim to be falsifiable (such as intelligent-design theory).
I don't think we will ever overcome the linguistic inertia that calls all of these "theories". If we want to be clearer, we should either insist on saying "falsifiable theory", no matter how cumbersome "Darwin's falsifiable theory of evolution by natural selection" may sound, or invent some new words.
From Timothy Surendonk
Krauss's recommendation that we remove the word "theory" from "string theory" is one that can only end in tears.
As he points out, it is a departure from the lay meaning of the word, and the confusion will only escalate when people hear the term used in scientifically allied fields such as macroeconomic theory, psychoanalytic theory and management theory - all with varying connection to the physical world.
Mathematical theories such as set theory, number theory and even computability theory don't even pretend to talk about the "real" world, yet we are happy to consider them to be in many ways scientific.
I think it is time we faced up to it: intelligent design, like string theory, is a theory. The pertinent issue is that it is not a very good theory.
Perhaps if we gave teachers some credit in their role as educators and recognised that children can and should develop the skill of critical thinking, then we would see that this is something actually worth teaching.
Kellyville Ridge, New South Wales, Australia
From Nigel Seel
Seen today in the "Science fiction and fantasy" section of a bookshop in London Heathrow airport, next to Dune by Frank Herbert: The Elegant Universe: Superstrings, hidden dimensions, and the quest for the ultimate theory by Brian Greene.
Andover, Hampshire, UK
From Paul Mealing
When I was studying philosophy, a lecturer told me that people often conflate the words "theory" and "hypothesis", which creates confusion, especially in relation to arguments concerning evolution and creationism. It was explained to me that a theory generates hypotheses that can be tested and that Popper's criterion of falsifiability applies to the hypotheses and not the theory. A theory that is unable to generate falsifiable hypotheses is not a scientific theory. According to this logic, when one has God's intervention as the only hypothesis to a theory (intelligent design), then it is not a scientific theory because its hypotheses are not falsifiable or testable.
String theory and all its variants are mathematical models attempting to resolve conflicts between quantum theory and relativity theory. Most science today is a combination of mathematics and empirical research, and when empirical results are thin or non-existent, mathematics becomes the only way forward, which is effectively what has happened in string theory.
String theory does generate hypotheses but we are not in a good position to test them, which is why Ed Witten said that string theory is 21st-century physics that accidentally found its way into the 20th century. You may wish to apply another moniker, but no one would suggest that string theory and ID have the same credence scientifically, if for no other reason than that one can be explored, albeit in the world of mathematics, and the other cannot be explored at all. ID (God made it so we can't explain it) is a bald statement that neither results from exploration nor generates it.
Science is foremost about exploration, and a theory that can't be explored has no currency, at least not in the scientific community. ID not only can't be explored, but it stops exploration, which is exactly what the creationists want. Despite their claims of being fair and open-minded, creationists, including ID proponents, are fiercely anti-science. They see science as humanistic, if not atheistic, inherently unethical, and the root cause of amoral policies on issues such as homosexuality, abortion and stem-cell research. They righteously believe that society will only find its moral compass when religion replaces science in children's classrooms.
One only has to look at the backlash George W. Bush has created in the US science community to appreciate how anti-science has already affected US policy and decision making, not to mention education.
Ivanhoe, Victoria, Australia
From Henry M. Harris
With all due respect to Krauss, I think his article is labouring under a false conception about language. Words do not have absolute meaning---they are context dependent. "Nerves of steel" does not mean your neurons are made of a carbon-iron alloy, and "sword of steel" does not mean your sword is hard but that it's made of the previously mentioned alloy. Likewise, "theory of the automobile engine" doesn't mean that automobile engines don't exist, while "string theory" is about something that may not exist.
Pasadena, California, US
From Crispin Piney
Krauss suggests that scientists should somehow explain to non-scientists - and especially creationists - that the term "theory" has a special meaning in science. I fear that this is doomed to failure and reminds me of Humpty-Dumpty insisting that words mean what you choose them to mean. I would reverse the approach and adopt the "it's only a theory" argument in the way the creationists apply it, and use it to encourage anti-evolutionists to experiment with the other "only a theory": that is to say the theory of gravitation. This is a valid comparison, since both gravitation and evolution can be shown to work; what is in debate is some of the fine detail of how they work.
I would therefore suggest that anti-evolutionists act courageously on their belief that any "only a theory" implies a non-existent effect and ignore Newton's theory of gravitation. Whereas it is less immediately dangerous to ignore evolution, the impact of ignoring the forces of gravity will possibly help convince them that an "only a theory" can be completely true - with the additional side effect of supporting Darwin's theory by removing a number of gravitational sceptics from the gene pool once and for all.
See: Original Article
Lawrence Krauss is quite right that we need to be much clearer about the role of falsifiability in making a theory "scientific" (3 December, p 23). Despite taking mostly science subjects at school and having intelligent, motivated teachers, I reached the end of my secondary education without the concept having been mentioned once.
However, I'm not sure whether Krauss's attempt to clarify the word "theory" will do the trick. "Theory" is used both in normal speech and in science to refer to all varieties of idea, from wild speculation to well-tested systems. Krauss mentions falsifiable theories (such as Newton's theory of gravity), unfalsifiable theories that are at least aiming to be falsifiable (such as string theory) and theories which do not aim to be falsifiable (such as intelligent-design theory).
I don't think we will ever overcome the linguistic inertia that calls all of these "theories". If we want to be clearer, we should either insist on saying "falsifiable theory", no matter how cumbersome "Darwin's falsifiable theory of evolution by natural selection" may sound, or invent some new words.
From Timothy Surendonk
Krauss's recommendation that we remove the word "theory" from "string theory" is one that can only end in tears.
As he points out, it is a departure from the lay meaning of the word, and the confusion will only escalate when people hear the term used in scientifically allied fields such as macroeconomic theory, psychoanalytic theory and management theory - all with varying connection to the physical world.
Mathematical theories such as set theory, number theory and even computability theory don't even pretend to talk about the "real" world, yet we are happy to consider them to be in many ways scientific.
I think it is time we faced up to it: intelligent design, like string theory, is a theory. The pertinent issue is that it is not a very good theory.
Perhaps if we gave teachers some credit in their role as educators and recognised that children can and should develop the skill of critical thinking, then we would see that this is something actually worth teaching.
Kellyville Ridge, New South Wales, Australia
From Nigel Seel
Seen today in the "Science fiction and fantasy" section of a bookshop in London Heathrow airport, next to Dune by Frank Herbert: The Elegant Universe: Superstrings, hidden dimensions, and the quest for the ultimate theory by Brian Greene.
Andover, Hampshire, UK
From Paul Mealing
When I was studying philosophy, a lecturer told me that people often conflate the words "theory" and "hypothesis", which creates confusion, especially in relation to arguments concerning evolution and creationism. It was explained to me that a theory generates hypotheses that can be tested and that Popper's criterion of falsifiability applies to the hypotheses and not the theory. A theory that is unable to generate falsifiable hypotheses is not a scientific theory. According to this logic, when one has God's intervention as the only hypothesis to a theory (intelligent design), then it is not a scientific theory because its hypotheses are not falsifiable or testable.
String theory and all its variants are mathematical models attempting to resolve conflicts between quantum theory and relativity theory. Most science today is a combination of mathematics and empirical research, and when empirical results are thin or non-existent, mathematics becomes the only way forward, which is effectively what has happened in string theory.
String theory does generate hypotheses but we are not in a good position to test them, which is why Ed Witten said that string theory is 21st-century physics that accidentally found its way into the 20th century. You may wish to apply another moniker, but no one would suggest that string theory and ID have the same credence scientifically, if for no other reason than that one can be explored, albeit in the world of mathematics, and the other cannot be explored at all. ID (God made it so we can't explain it) is a bald statement that neither results from exploration nor generates it.
Science is foremost about exploration, and a theory that can't be explored has no currency, at least not in the scientific community. ID not only can't be explored, but it stops exploration, which is exactly what the creationists want. Despite their claims of being fair and open-minded, creationists, including ID proponents, are fiercely anti-science. They see science as humanistic, if not atheistic, inherently unethical, and the root cause of amoral policies on issues such as homosexuality, abortion and stem-cell research. They righteously believe that society will only find its moral compass when religion replaces science in children's classrooms.
One only has to look at the backlash George W. Bush has created in the US science community to appreciate how anti-science has already affected US policy and decision making, not to mention education.
Ivanhoe, Victoria, Australia
From Henry M. Harris
With all due respect to Krauss, I think his article is labouring under a false conception about language. Words do not have absolute meaning---they are context dependent. "Nerves of steel" does not mean your neurons are made of a carbon-iron alloy, and "sword of steel" does not mean your sword is hard but that it's made of the previously mentioned alloy. Likewise, "theory of the automobile engine" doesn't mean that automobile engines don't exist, while "string theory" is about something that may not exist.
Pasadena, California, US
From Crispin Piney
Krauss suggests that scientists should somehow explain to non-scientists - and especially creationists - that the term "theory" has a special meaning in science. I fear that this is doomed to failure and reminds me of Humpty-Dumpty insisting that words mean what you choose them to mean. I would reverse the approach and adopt the "it's only a theory" argument in the way the creationists apply it, and use it to encourage anti-evolutionists to experiment with the other "only a theory": that is to say the theory of gravitation. This is a valid comparison, since both gravitation and evolution can be shown to work; what is in debate is some of the fine detail of how they work.
I would therefore suggest that anti-evolutionists act courageously on their belief that any "only a theory" implies a non-existent effect and ignore Newton's theory of gravitation. Whereas it is less immediately dangerous to ignore evolution, the impact of ignoring the forces of gravity will possibly help convince them that an "only a theory" can be completely true - with the additional side effect of supporting Darwin's theory by removing a number of gravitational sceptics from the gene pool once and for all.
Tuesday, May 22, 2007
Astronomy & the Scientific Method
An excellent history of the different philosophic views of our universe, with reference to the Scientific Method and eventually Galileo
Pellagra - The search for a cure
This is designed to explain the Scientific Method whilst explaining how it was used in the search for a cure for a disease
The Scientific Method - Alien Experiment
This is an experiment designed to show you the principles behind the Scientific Method. You will need a pen or pencil.
Friday, May 18, 2007
Homeopathy - Put to the Test
This is a BBC Horizon programme that shows an investigation using the scientific method into Homeopathy.
Saturday, May 12, 2007
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