Layman here, I can't help but notice the similarities of how 19th century scientists describe an aether with magical properties to help plug holes in their theories to dark matter.
1. "Dark matter is a hypothetical kind of matter that cannot be seen with telescopes but accounts for most of the matter in the Universe."
2. "It is hypothesized to be matter that does not react to light."
3. "Astrophysicists hypothesized dark matter because of discrepancies between the mass of large astronomical objects determined from their gravitational effects and the mass calculated from the observable matter (stars, gas, and dust) that they can be seen to contain."
4. "dark matter — that exerts a well-understood gravitational force but neither absorbs nor emits light, and doesn’t collide (as far as we can tell) with protons, neutrons or electrons. So while normal matter (in pink, below) slows down and can even stick together when it runs into other normal matter, dark matter (in blue, below) just passes right through both itself and all other forms of matter."
In the sense that dark matter is a theoretical entity that is invoked to explain a particular set of astronomical observations, this is a fair comparison. Late 19th century critics of aether might have compared it to caloric (a theoretical entity that explained a particular set of thermodynamic observations.) Caloric turned out not to exist.
By the same token, we might compare dark matter to neutrinos, which were a theoretical entity invoked to explain a particular set of observations on radioactivity (the shape of the beta spectrum.) Neutrinos turned out to exist.
As such, while the comparison to aether is superficially apt, it is not something we can draw any conclusions from, because the comparison to the neutrino is equally apt.
Science is the discipline of publicly testing ideas by systematic observation, controlled experiment and Bayesian inference. It is not the discipline of testing ideas by making analogies to other ideas. There is a reason for this: making analogies to other ideas has consistently proven to be almost completely useless for creating knowledge of reality, while the discipline of science has been wildly successful.
Nor are the properties of caloric, aether, neutrinos or dark matter "magical". They are merely the ones required of an entity that is able to explain our observations in each instance. In the case of caloric it turned out to have self-contradictory properties, when the full deductive closure of the theory was teased out. In the case of aether it turned out to have properties that made predictions that were false. In the case of neutrinos the required properties made predictions that were true.
In the case of dark matter: we don't know yet, and the only way we will ever know is if we continue on with our program of systematic observation, controlled experiment and Bayesian inference. There is no other way to know.
Your first two sentences is what I was trying to describe.
I may be addressing a straw man here, but anyways;
I would contest this that analogy is completely useless for creating knowledge of reality.
Analogy is a tool to translate facts into thoughts another person can understand. Physicists describe Dark matter as an analogy to matter with exceptions to make it easier for others to understand what they're looking for. "It is like matter, except in these ways". If it works as a tool of human communication, and creating knowledge of reality requires human communication, then it is a tool that can be potentially useful.
Humans, unlike machines, rely on human interaction to cooperate. It is one thing to say the scientific method is very useful in describing the underlying reality in which we all exist, and yet something else altogether to show disdain to all other kinds of thinking. The scientific method is a tool at humanity disposal, to believe human thinking and human knowledge can be reduced to Science with a capital "S" is to mock it.
I believe the parent was intentionally particular in its choice of words on this point, and perhaps you've glossed over that intentionality, as well as how it differs from your idea here.
The original:
> "... making analogies to other ideas has consistently proven to be almost completely useless for creating knowledge of reality ..."
vs your statement:
> "Analogy is a tool to translate facts into thoughts another person can understand ... If it works as a tool of human communication, and creating knowledge of reality requires human communication, then it is a tool that can be potentially useful."
The parent is talking about creating knowledge of reality by systematic observation, controlled experimentation, and Bayesian inference--and then repeating that process based on the results and predictions of the process to gradually create knowledge of reality previously unknown. However, you're pointing to communicating knowledge of reality in a more understandable and relatable format.
I do not think the parent was showing any "disdain to all other kinds of thinking"--because analogies are not another kind of thinking, but are a tool for communication.
Analogies cannot be tested and judged on their predictive capabilities. You cannot infer new knowledge of reality from analogies. The most rigorous test one can subject analogies to is determining whether they are, in fact, homologous. You can use analogies to [usually poorly] communicate knowledge of reality to those who do not already understand it, relating unknown knowledge to something already known, familiar, and understood. This can help a person grasp this knowledge where s/he previously did not. However, analogies do not allow for systematic study, testing, experimenting, predicting, etc.--all the things the scientific method allows. One cannot make Bayesian inferences from analogies--how exactly would such a thing work? The most one can do with analogies is use them to lubricate a conversation when one finds it necessary to help someone lacking the requisite verbal or technical understanding join the discussion.
If you'll grant that we can obtain both verbal and technical understanding of any given piece of knowledge, analogies help obtain the former, but can do nothing for the latter. That is, analogies help increase verbal understanding by facilitating easier communication, but they do nothing for arriving at technical understanding or discovering knowledge in the first place.
I know HN frowns on this type of comment, but this is a first class response to a question I think a lot of people have, both in this area of cosmology and more generally about science as a framework for developing understanding. Thanks for taking the time, and to the parent for asking a question I wasn't brave enough to voice.
Comments
Layman here, I can't help but notice the similarities of how 19th century scientists describe an aether with magical properties to help plug holes in their theories to dark matter.
1. "Dark matter is a hypothetical kind of matter that cannot be seen with telescopes but accounts for most of the matter in the Universe."
2. "It is hypothesized to be matter that does not react to light."
3. "Astrophysicists hypothesized dark matter because of discrepancies between the mass of large astronomical objects determined from their gravitational effects and the mass calculated from the observable matter (stars, gas, and dust) that they can be seen to contain."
4. "dark matter — that exerts a well-understood gravitational force but neither absorbs nor emits light, and doesn’t collide (as far as we can tell) with protons, neutrons or electrons. So while normal matter (in pink, below) slows down and can even stick together when it runs into other normal matter, dark matter (in blue, below) just passes right through both itself and all other forms of matter."
It sounds to me like a kind of Aether 2.0.
In the sense that dark matter is a theoretical entity that is invoked to explain a particular set of astronomical observations, this is a fair comparison. Late 19th century critics of aether might have compared it to caloric (a theoretical entity that explained a particular set of thermodynamic observations.) Caloric turned out not to exist.
By the same token, we might compare dark matter to neutrinos, which were a theoretical entity invoked to explain a particular set of observations on radioactivity (the shape of the beta spectrum.) Neutrinos turned out to exist.
As such, while the comparison to aether is superficially apt, it is not something we can draw any conclusions from, because the comparison to the neutrino is equally apt.
Science is the discipline of publicly testing ideas by systematic observation, controlled experiment and Bayesian inference. It is not the discipline of testing ideas by making analogies to other ideas. There is a reason for this: making analogies to other ideas has consistently proven to be almost completely useless for creating knowledge of reality, while the discipline of science has been wildly successful.
Nor are the properties of caloric, aether, neutrinos or dark matter "magical". They are merely the ones required of an entity that is able to explain our observations in each instance. In the case of caloric it turned out to have self-contradictory properties, when the full deductive closure of the theory was teased out. In the case of aether it turned out to have properties that made predictions that were false. In the case of neutrinos the required properties made predictions that were true.
In the case of dark matter: we don't know yet, and the only way we will ever know is if we continue on with our program of systematic observation, controlled experiment and Bayesian inference. There is no other way to know.
Your first two sentences is what I was trying to describe.
I may be addressing a straw man here, but anyways;
I would contest this that analogy is completely useless for creating knowledge of reality.
Analogy is a tool to translate facts into thoughts another person can understand. Physicists describe Dark matter as an analogy to matter with exceptions to make it easier for others to understand what they're looking for. "It is like matter, except in these ways". If it works as a tool of human communication, and creating knowledge of reality requires human communication, then it is a tool that can be potentially useful.
Humans, unlike machines, rely on human interaction to cooperate. It is one thing to say the scientific method is very useful in describing the underlying reality in which we all exist, and yet something else altogether to show disdain to all other kinds of thinking. The scientific method is a tool at humanity disposal, to believe human thinking and human knowledge can be reduced to Science with a capital "S" is to mock it.
I believe the parent was intentionally particular in its choice of words on this point, and perhaps you've glossed over that intentionality, as well as how it differs from your idea here.
The original:
vs your statement:
The parent is talking about creating knowledge of reality by systematic observation, controlled experimentation, and Bayesian inference--and then repeating that process based on the results and predictions of the process to gradually create knowledge of reality previously unknown. However, you're pointing to communicating knowledge of reality in a more understandable and relatable format.
I do not think the parent was showing any "disdain to all other kinds of thinking"--because analogies are not another kind of thinking, but are a tool for communication.
Analogies cannot be tested and judged on their predictive capabilities. You cannot infer new knowledge of reality from analogies. The most rigorous test one can subject analogies to is determining whether they are, in fact, homologous. You can use analogies to [usually poorly] communicate knowledge of reality to those who do not already understand it, relating unknown knowledge to something already known, familiar, and understood. This can help a person grasp this knowledge where s/he previously did not. However, analogies do not allow for systematic study, testing, experimenting, predicting, etc.--all the things the scientific method allows. One cannot make Bayesian inferences from analogies--how exactly would such a thing work? The most one can do with analogies is use them to lubricate a conversation when one finds it necessary to help someone lacking the requisite verbal or technical understanding join the discussion.
If you'll grant that we can obtain both verbal and technical understanding of any given piece of knowledge, analogies help obtain the former, but can do nothing for the latter. That is, analogies help increase verbal understanding by facilitating easier communication, but they do nothing for arriving at technical understanding or discovering knowledge in the first place.
I know HN frowns on this type of comment, but this is a first class response to a question I think a lot of people have, both in this area of cosmology and more generally about science as a framework for developing understanding. Thanks for taking the time, and to the parent for asking a question I wasn't brave enough to voice.