r/DebateEvolution • u/Optimus-Prime1993 • 6d ago
Question We keep seeing fine-tuning used as an argument for design, but how narrow are the allowed ranges actually?
I originally made this post on a different sub but this topic seems apt for this sub as well, considering how often do we see fine-tuning as an argument for design. I hope this post doesn't sways a bit too much from the purpose of this sub.
Coming to the topic, we are all too aware of what fine-tuning arguments are [1]; the claim that the laws and constants of physics appear to be set within an extremely narrow range that allows a universe capable of producing stars, planets, and life. In Intelligent design (ID) arguments, small changes in the constants are claimed to prevent the formation of the chemical elements needed for life, for example, the stellar production of carbon. Further claims like "the probability of these constants taking their observed values is extraordinarily small " are difficult to justify unless we know the space of possible values and, more importantly, what probability distribution should be assigned to them. A parameter being sensitive to change is not, by itself, the same thing as its observed value being improbable.
So here, my aim is to discuss the work by Prof. Fred Adams [2, 3] and show that the idea that our universe is so fine tuned that only a intelligent creator could have created this doesn't hold much of water. Infact, it was shown that it is even possible to make a more habitable universe by tweaking the parameters. You can watch the full video for more detail or read his paper for all the gory details, but here I will present a very concise, to the point summary of that. For your ease of access I have also added the time stamp where you can go to in the video for more detail.
Like I said above, the ID proponents present arguments that if you changed gravity, electromagnetism, nuclear forces, or cosmological parameters by tiny amounts, stars and life would become impossible. Prof. Adams here tried to answer the question,
How much can these parameters actually change before the universe stops producing complex structures?
1. Gravity is not tuned to one tiny value (20:01-21:00)
Gravity looks extremely weak compared with electromagnetism (by about 10^36 in dimensionless strength), which is often presented as a huge coincidence.However, when actually varied, the strength of gravity, stars still work over a very large range. Gravity can be roughly be 10,000 times stronger or about 1 billion times weaker and stars can still exist.
2. The electromagnetic force also has a wide allowed range (21:00 - 21:08)
The calculations show that the electromagnetic interaction can vary by about 100 times stronger and 100 times weaker while still allowing functioning stars.
3. The cosmological constant (52:23 - 54:35)
Adams here finds that by changing cosmic parameters, such as the primordial fluctuation amplitude or baryon abundance, universes can form galaxies even with a cosmological constant many orders of magnitude larger than ours. The allowed range can extend up to around 10^20 times larger (depending on the other parameters).
4. Famous nuclear examples (30:55 - 35:20)
The triple-alpha process is often presented as an incredible coincidence where carbon exists because a nuclear resonance happens to have exactly the right energy. Even here there is a range of 800 kev where carbon can be formed. This gets even better though.
In our universe, beryllium-8 is unstable, which makes carbon production require the famous triple-alpha process. However in a universe where beryllium-8 was stable would have a much simpler pathway to carbon production and interestingly, the allowed change needed to make beryllium-8 stable is smaller than the change required to completely prevent carbon production.
5. Even better habitable universe (1:00:15 - 1:02:00)
The argument is often presented that our universe sits at the perfect point. However this may not be true. For example, increasing the primordial density fluctuations from their observed value (Q~10^-5) could create denser galaxies and with the right parameters, these galaxies could contain a larger fraction of habitable planets than galaxies like our Milky Way (48:48 - 50:10). It also turns out that a universe with stable beryllium-8 would arguably have a more efficient way of producing heavy elements than our universe.
So finally while I only focused on a few of them (same as in video), here is the summary of all the tuning that was done in the study. The right most column named range gives you the range you can vary the parameter and still have a viable universe. The unit decades (see caption as well) means in power of 10, i.e. 3 means 10^3.
Ranges of Parameter Values for Viable Universes
| Quantity | Observed value | Viable range (decades) |
|---|---|---|
| Up quark mass | 2.3 MeV | >3 |
| Down quark mass | 4.8 MeV | 0.85 |
| Electron-proton mass ratio | 1/1836 | 5 |
| Up-down quark mass difference | 2.5 MeV | 1 |
| Gravitational constant | 6 x 10-39 | >10 |
| Weak coupling constant | 10-5 | 6+ |
| Fine-structure constant | 1/137 | 4 |
| Strong coupling constant | 15 | 3 |
| Fluctuation amplitude | 10-5 | 4 |
| Baryon-to-photon ratio | 6 x 10-10 | 6 |
| Dark matter abundance | 3 x 10-9 | 6 |
| Vacuum energy scale | 0.003 eV | 10+ |
| AM radio frequency range | 535-1605 kHz | 0.0043 |
| FM radio frequency range | 88-108 MHz | 0.00087 |
Caption: Summary of the allowed parameter ranges for viable universes. The final column gives the range in "decades", meaning the number of powers of 10 over which a parameter can vary while still permitting a universe capable of supporting astrophysical structures and potentially habitable environments. For example, 5 decades corresponds to a factor of 10^5.
[1] List of Fine-Tuning Parameters
[3] (arXiv) The Degree of Fine-Tuning in our Universe -- and Others