Interview with Bjørn Ekeberg, philosopher of science, author of Metaphysical Experiments
https://iai.tv/articles/the-delusions-of..._auid=2020
INTRO: The idea that the universe started with a Big Bang is a key tenet of the standard model of cosmology. But that model is a lot less scientific than it’s taken to be. To begin with, we can never have direct evidence of the Big Bang itself, and so if we are to accept it, it must be as a metaphysical, not a scientific hypothesis.
Furthermore, the standard model of cosmology has had to adapt to a number of observational discrepancies, postulating entities like dark matter and dark energy for which there is no direct evidence.
To add to the above, another central assumption, the cosmological principle, stating that the laws of the universe are the same everywhere, is also under scrutiny. The universe might turn out to be a lot stranger than we think, or could possibly imagine, argues Bjørn Ekeberg... (MORE - the interview)
Where is physics going? Featuring Sabine Hossenfelder, Bjørn Ekeberg & Sam Henry ... https://youtu.be/b8npmtsfsTU
https://www.youtube-nocookie.com/embed/b8npmtsfsTU
How the Multiverse could break the scientific method
https://bigthink.com/13-8/multiverse-tes...ic-method/
EXCERPTS: In high energy physics, all the characters are fields. Fields, here, mean disturbances that fill space and may or may not change in time. A crude picture of a field is that of water filling a pond. The water is everywhere in the pond, with certain properties that take on values at every point: temperature, pressure, and salinity, for example. Fields have excitations that we call particles. The electron field has the electron as an excitation. The Higgs field has the Higgs boson. In this simple picture, we could visualize the particles as ripples of water propagating along the surface of the pond. This is not a perfect image, but it helps the imagination.
The most popular protagonist driving inflationary expansion is a scalar field [...] We do not know if there were scalar fields at the cosmic infancy, but it is reasonable to suppose there were. ... As mentioned above, when we do not have data, the best that we can do is to build reasonable hypotheses that future experiments will hopefully test.
To see how we use a scalar field to model inflation, picture a ball rolling downhill. As long as the ball is at a height above the bottom of the hill, it will roll down. It has stored energy. At the bottom, we set its energy to zero. We do the same with the scalar field. As long as it is displaced from its minimum, it will fill the Universe with its energy. In large enough regions, this energy prompts the fast expansion of space that is the signature of inflation.
Linde and Vilenkin added quantum physics to this picture. In the world of the quantum, everything is jittery; everything vibrates endlessly. This is at the root of quantum uncertainty [...] So as the field is rolling downhill, it is also experiencing these quantum jumps, which can kick it further down or further up. ... Choppy waters, these quantum fields.
Here comes the twist: When a sufficiently large region of space is filled with the field of a certain energy, it will expand at a rate related to that energy. [...] The result for cosmology is a plethora of madly inflating regions of space, each expanding at its own rate. Very quickly, the Universe would consist of myriad inflating regions that grow, unaware of their surroundings. The Universe morphs into a Multiverse. Even within each region, quantum fluctuations may drive a sub-region to inflate. The picture, then, is one of an eternally replicating cosmos, filled with bubbles within bubbles. Ours would be but one of them — a single bubble in a frothing Multiverse.
[...] We are thus stuck with a plausible scientific idea that seems untestable. Even if we were to find evidence for inflation, that would not necessarily support the inflationary Multiverse. What are we to do?
The Multiverse suggests another ingredient — the possibility that physics is different in different universes [...] In order to harbor life as we know it, our Universe has to obey a series of very strict requirements. Small deviations are not tolerated in the values of nature’s constants.
[...] To know whether we are common, we need to know something about the other universes and the kinds of physics they have. But we don’t.
[...] That is why some physicists worry about the Multiverse to the point of loathing it. There is nothing more important to science than its ability to prove ideas wrong. If we lose that, we undermine the very structure of the scientific method... (MORE - missing details)
https://iai.tv/articles/the-delusions-of..._auid=2020
INTRO: The idea that the universe started with a Big Bang is a key tenet of the standard model of cosmology. But that model is a lot less scientific than it’s taken to be. To begin with, we can never have direct evidence of the Big Bang itself, and so if we are to accept it, it must be as a metaphysical, not a scientific hypothesis.
Furthermore, the standard model of cosmology has had to adapt to a number of observational discrepancies, postulating entities like dark matter and dark energy for which there is no direct evidence.
To add to the above, another central assumption, the cosmological principle, stating that the laws of the universe are the same everywhere, is also under scrutiny. The universe might turn out to be a lot stranger than we think, or could possibly imagine, argues Bjørn Ekeberg... (MORE - the interview)
Where is physics going? Featuring Sabine Hossenfelder, Bjørn Ekeberg & Sam Henry ... https://youtu.be/b8npmtsfsTU
How the Multiverse could break the scientific method
https://bigthink.com/13-8/multiverse-tes...ic-method/
EXCERPTS: In high energy physics, all the characters are fields. Fields, here, mean disturbances that fill space and may or may not change in time. A crude picture of a field is that of water filling a pond. The water is everywhere in the pond, with certain properties that take on values at every point: temperature, pressure, and salinity, for example. Fields have excitations that we call particles. The electron field has the electron as an excitation. The Higgs field has the Higgs boson. In this simple picture, we could visualize the particles as ripples of water propagating along the surface of the pond. This is not a perfect image, but it helps the imagination.
The most popular protagonist driving inflationary expansion is a scalar field [...] We do not know if there were scalar fields at the cosmic infancy, but it is reasonable to suppose there were. ... As mentioned above, when we do not have data, the best that we can do is to build reasonable hypotheses that future experiments will hopefully test.
To see how we use a scalar field to model inflation, picture a ball rolling downhill. As long as the ball is at a height above the bottom of the hill, it will roll down. It has stored energy. At the bottom, we set its energy to zero. We do the same with the scalar field. As long as it is displaced from its minimum, it will fill the Universe with its energy. In large enough regions, this energy prompts the fast expansion of space that is the signature of inflation.
Linde and Vilenkin added quantum physics to this picture. In the world of the quantum, everything is jittery; everything vibrates endlessly. This is at the root of quantum uncertainty [...] So as the field is rolling downhill, it is also experiencing these quantum jumps, which can kick it further down or further up. ... Choppy waters, these quantum fields.
Here comes the twist: When a sufficiently large region of space is filled with the field of a certain energy, it will expand at a rate related to that energy. [...] The result for cosmology is a plethora of madly inflating regions of space, each expanding at its own rate. Very quickly, the Universe would consist of myriad inflating regions that grow, unaware of their surroundings. The Universe morphs into a Multiverse. Even within each region, quantum fluctuations may drive a sub-region to inflate. The picture, then, is one of an eternally replicating cosmos, filled with bubbles within bubbles. Ours would be but one of them — a single bubble in a frothing Multiverse.
[...] We are thus stuck with a plausible scientific idea that seems untestable. Even if we were to find evidence for inflation, that would not necessarily support the inflationary Multiverse. What are we to do?
The Multiverse suggests another ingredient — the possibility that physics is different in different universes [...] In order to harbor life as we know it, our Universe has to obey a series of very strict requirements. Small deviations are not tolerated in the values of nature’s constants.
[...] To know whether we are common, we need to know something about the other universes and the kinds of physics they have. But we don’t.
[...] That is why some physicists worry about the Multiverse to the point of loathing it. There is nothing more important to science than its ability to prove ideas wrong. If we lose that, we undermine the very structure of the scientific method... (MORE - missing details)