Here are the main fallacies Adams is guilty of:
- The
“ant near the needle hole” fallacy of visually representing
something incredibly unlikely to make it look as if it is likely
- The
fallacy of considering any type of star allowing life
when considering stars and cosmic fine-tuning, while not
considering the equally important likelihood of stars as
suitable for life's evolution as our own sun
- The
fallacy of considering only less sensitive requirements when
considering the likelihood of stars existing, and ignoring a vastly
more sensitive requirement which makes the existence of stars
incredibly unlikely in random universes
- The
fallacy of ignoring the universe's most dramatic cases of cosmic
fine-tuning, and focusing only on less dramatic cases
Adams' scientific specialty is stars. He gives us a graph that plots possible strengths of the electromagnetic force and the gravitational force in hypothetical possible universes. A shaded portion taking up a fairly large part of the graph is described as an area “consistent with life.” The graph makes clear that stars require an unlikely balance between the gravitational force and the electromagnetic force, but from looking at the graph you might think that such a thing wasn't all that unlikely.
Adams here is guilty of a fallacy that we might call the fallacy of the “ant near the needle hole.” Consider an ant that somehow wanders into your sewing kit. If it were smart enough to talk, the ant might look at the eye of a needle hole in your sewing kit, and say, “Wow, that's a big needle hole!” Such an observation will only be made if you have a perspective looking a few millimeters away from the needle hole.
Given
such a parameter space, a realistic visual representation of the
chance of a random universe having parameters allowing stars to exist would be one
like the visual below, which shows a tiny needle hole somewhere in
the Grand Canyon. It is therefore correct to say that with
overwhelming likelihood, a random universe would not have stars.
Since stars are necessary for both light and life to exist, it is
correct to say that with overwhelming likelihood, a random universe
would be lifeless and light-less.
The
misleading nature of Adams' graph is discussed on page 40 of this
excellent scientific paper by physicist Luke Barnes, who concludes (contrary to
Adams) that “the existence of stable stars is indeed a fine-tuned
property of our universe.”
Among the stars in our universe are short-lived blue stars, long-lived yellow stars like our sun, and much less bright “red dwarf” stars that are very long-lived. It could be that life exists on planets around red dwarf stars, but it is almost universally recognized that life is much less probable to arise on planets revolving around such stars. There are two main reasons, discussed fully here. One is that since red dwarf stars are much dimmer, a planet would have to be fairly close to a red dwarf star for life to exist on the planet; and at such closer distances the planet would be subjected to very troublesome tidal effects that might make it uninhabitable. The second reason is that red dwarf stars are more unstable than stars like our sun; as a wikepedia.org article says, “Red dwarfs are far more variable and violent than their more stable, larger cousins,” such as our sun. Such variability would make a planet near a red star much more likely to get zapped by crippling radiation.
If gravity were very slightly weaker, or electromagnetism very slightly stronger (or the electron slightly less massive relative to the proton), all stars would be red dwarfs. A correspondingly tiny change the other way, and they would all be blue giants.
So
we can put it this way: it is incredibly unlikely that a random
universe would have any stars, and super-incredibly unlikely that a
random universe would have sun-like stars. Clearly we should pay
attention to both of these probabilities when judging how fine-tuned
the universe is.
I
can give an analogy. Suppose you walk deeply into the wooded
wilderness of a national park with your friend, and come across a log
cabin. You may say, “That must have been fine-tuned” or “That
must have been designed.” Now your friend may say, “Not so,
because trees might have fallen in such a way to provide you with
some type of shelter from the rain.” This is fallacious, because
the relevant thing to consider is the most fine-tuned thing you see,
not some other less suitable thing that luck might have given you.
And similarly, when considering fine-tuning in regard to stars, we
should be noting that the requirements of the most suitable types of
stars (stars like our sun) are much, much more stringent than the
requirements of “some type of stars.” Adams ignores these more
stringent requirements.
The
third fallacy Adams commits is the fallacy of considering only some
of the less stringent requirements of stars, while ignoring the most
stringent requirement for stars. The most stringent requirement of
stars is that the proton charge exactly balance the electron charge.
This requirement has been pointed out by the astronomer Greenstein,
who pointed out that no stars could exist if the proton charge did
not exactly match the electron charge.
If
there was a very small difference between the electron charge and the
proton charge, you would either have (1) an electrical imbalance
between particles which would completely overwhelm gravity, making it
impossible for stars to hold together, or (2) an electrical
imbalance between particles that would completely preclude the
possibility of the thermonuclear reactions we observe in stars.
In
our universe each proton has a mass 1836 times larger than each
electron, but the charge of the proton exactly matches the charge of
the electron to at least eighteen decimal places, as measured here (the only difference being that
the proton has a positive charge and the electron has a negative
charge). Stars could not possibly exist if this precise fine-tuning
did not exist. Adams has simply ignored this ultra-stringent requirement,
focusing on less stringent requirements. Were he to consider this
requirement, he might realize that stars are trillions of times less
probable to exist in random universe than he imagines.
I
may note that this requirement is an entirely different requirement
than the one previously considered. So for a random universe to have
stars, it must not only “thread the needle” involving the balance
of the gravitational and electromagnetic force (the balance that
Adams has considered), but a random universe would also have to
“thread the microscopic needle” of having the proton charge exactly match the electron charge. So it is as if the arrow of the
blind archer must hit not just one very distant bulls-eye for stars
to exist, but two very distant bulls-eyes.
We
are then doubly justified in saying: with overwhelming likelihood, a
random universe would be both lifeless and light-less.
The
fourth fallacy that Adam commits is the fallacy of ignoring the
universe's most dramatic cases of fine-tuning, and focusing only on
less dramatic cases. The three most dramatic cases of cosmic
fine-tuning all seemingly involve fine-tuning more precise than 1
part in 1,000,000,000,000,000,000,000,000. They are:
- the exact match of the absolute magnitude of the proton charge and the electron charge, to more than 18 decimal places
- the fine-tuning of the vacuum energy density, discussed here, by which we have a cosmological constant more than 1050 times smaller than the amount predicted by quantum field theory (such as we would have if opposing parameters of nature accidentally canceled out each other to more than fifty decimal places)
- the fine-tuning of the universe's initial expansion rate (in which the universe's initial critical density matched the actual density to something like 1 part in 1050).
Which
of these does Adams discuss in his Nautilus essay? None of them. Of course, he does not
want to discuss such things as they would obliterate his claim that “our universe does not seem to be particularly fine-tuned.”
Adams
is very well aware of the cosmological constant problem (also known
as the vacuum density problem and the “vacuum catastrophe”
problem), because he discusses it at length in a scientific paper he
co-authored. There he gives us some reasoning that is as
off-the-mark as his insinuations about the likelihood of accidental
universes having stars.
The
issue in regard to the cosmological constant is that quantum field
theory predicts the cosmological constant should be 1060
or 10120 times larger than the value we observe. This
prediction (which you can find discussion of by doing a Google search
for “worst prediction in the history of physics”) is that the
vacuum of space should be super-dense – much denser than steel.
But the actual vacuum of space has very little energy or density –
it's almost empty.
We
know that life could never exist if the vacuum was anything like that
predicted by quantum field theory. Obviously you can't have life if
the space between a star and a planet is thicker than steel – light
cannot even travel through that. But an interesting question is: by
how much could the cosmological constant differ from its current
value and still allow life to exist?
Adams concludes that the cosmological constant could be up to 1030 times larger and still allow life to exist. This is almost certainly a far-too-generous estimate, and other estimates have estimated much greater sensitivity. He uses this estimate to support a conclusion in the paper that “the universe is not overly fine-tuned.” But he should be reaching exactly the opposite conclusion from these facts. If the cosmological constant is supposed to be 1060 or 10120 times larger than the value we observe because of quantum considerations, and a value 1030 times larger than the observed value would have prevented life, then how much luck did we have in this regard to have a habitable universe? The answer is: luck with a probability of about 1 part in 1030 or 1 part in 1090. Adams should have reached the conclusion that the universe is astonishingly fine-tuned, in a way that less than 1 universe in a billion trillion should have by chance.
This fine-tuning requirement is correctly stated in a 2014 scientific paper which tells us on page 16 that in order for you to have abundant quantities of oxygen and carbon, you need for the quark masses to be within 2 to 3 percent of their current values, and you also need for the fine-structure constant to be within 2.5% of its current value. You could therefore say nature has to hit two different “holes in one,” and these aren't the only “holes in one” nature has to hit in order to end up with intelligent life. Because these two “holes in one” that nature must hit are different from the two other “holes in one” I discussed before, while discussing stars.
Another bit of sloppy thinking Adams gives in his Nautilus essay is when he attempts to explain away a fine-tuning of the strong nuclear force by claiming that if some alternate physics were true, "The longest-lived stars could shine with a power output roughly comparable to the sun for up to 1 billion years, perhaps long enough for biological evolution to take place." This is laughable, since earthly life is believed to have required 3.5 billion years to have appeared; and obviously a universe in which stars like ours can burn brightly for 10 billion years is greatly preferable to one in which they can only burn for 1 billion years. Again, I may note that you do not explain a more favorable case of fine-tuning by imagining some much less favorable situation requiring less fine-tuning.
In
his Nautilus essay, Adams misreads what nature is telling
us, and his conclusion that “our universe does not seem to be
particularly fine-tuned” is very much at odds with both the facts and
the statements of numerous other scientists with a variety of
philosophical standpoints, who have again and again stated the opposite.
Postscript: I may note based purely on Adam's graph plotting the electromagnetic force versus the gravitational force and a life-compatible region, and the fact that the potential parameter space in random universes is more than a billion trillion times larger than the parameter space he has graphed, we should conclude that the chance of stars in a random universe is less than 1 in a billion trillion (less than 1 in 1,000,000,000,000,000,000,000). The requirement of the proton charge matching the electron charge is simply a second reason for drawing the same conclusion.
Postscript: I may note based purely on Adam's graph plotting the electromagnetic force versus the gravitational force and a life-compatible region, and the fact that the potential parameter space in random universes is more than a billion trillion times larger than the parameter space he has graphed, we should conclude that the chance of stars in a random universe is less than 1 in a billion trillion (less than 1 in 1,000,000,000,000,000,000,000). The requirement of the proton charge matching the electron charge is simply a second reason for drawing the same conclusion.
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