"The Privileged Planet"- revisited

In fact, no amount of evidence for apparent design could ever count as evidence of actual design. But if science is a search for the best explanation, based on the actual evidence from the physical world, rather than merely a search for the best materialistic or impersonal explanations of the physical world, how responsible is it to adopt a principle that makes one incapable of seeing an entire class of evidence?- page 270

Guillermo Gonzalez, one of the authors of “The Privileged Planet”, was a (Carl) Sagonite. However the book refutes Sagan.

It was Gonzalez’s paper “Wonderful Eclipses,” Astronomy & Geophysics 40, no. 3 (1999): 3.18- 3.20), that peaked the book’s co-author’s (Jay Richards) interest.

Gonzalez was part of a team of scientists working for NASA on a project trying to determine whether or not there is life “out there”.

At least one peer-reviewed paper (G. Gonzalez, D. Brownlee, and P.D. Ward, “The Galactic Habitable Zone: Galactic Chemical Evolution”, Icarus 152 (2001):185-200) came from that scientific research.

The authors make predictions. For example if/ when we discover other complex life is found elsewhere in the universe, the many factors observed here will also be present there. And that life will be carbon based.

“The same narrow circumstances that allow us to exist also provide us with the best over all conditions for making scientific discoveries.”

“The one place that has observers is the one place that also has perfect solar eclipses.”

“There is a final, even more bizarre twist. Because of Moon-induced tides, the Moon is gradually receding from Earth at 3.82 centimeters per year. In ten million years will seem noticeably smaller. At the same time, the Sun’s apparent girth has been swelling by six centimeters per year for ages, as is normal in stellar evolution. These two processes, working together, should end total solar eclipses in about 250 million years, a mere 5 percent of the age of the Earth. This relatively small window of opportunity also happens to coincide with the existence of intelligent life. Put another way, the most habitable place in the Solar System yields the best view of solar eclipses just when observers can best appreciate them.”

“The combined circumstance that we live on Earth and are able to see stars- that the conditions necessary for life do not exclude those necessary for vision, and vice versa- is a remarkably improbable one.

This is because the medium we live is, on one hand, just thick enough to enable us to breathe and prevent us from being burned up by cosmic rays, while, on the other hand, it is not so opaque as to absorb entirely the light of the stars and block the view of the universe. What a fragile balance between the indispensable and the sublime.” Hans Blumenberg- thoughts independent of the research done by Gonzalez.

Other G. Gonzalez papers that were the basis of the book (just skimming through the references):
“Stars, Planets, and Metals”, Reviews of Modern Physics 75 (2003)101-120
“Rummaging Through Earth’s Attic for Remains of Ancient Life”, Icarus 160 (2002) 183-196
“Is the Sun Anomalous?”, Astronomy and Geophysics 40, no. 5 (1999):5.25-5.29
“Are Stars with Planets Anomalous?”, Monthly Notices of the Royal Astronomical Society 308 (1999): 447-458
“Impact Reseeding During the Late Heavy Bombardment”, Icarus 162 (2003):38-46
“Parent Stars of Extrasolar Planets III: p Cancri Revisited”, Astronomy and Astrophysics 339 (1998): L29-L32
“Stellar Atmospheres of Nearby Young Solar Analogs”, New Astronomy 7 (2002): 211-226


Chapter 16 offers a “Skeptical Rejoinder” answering the following 14 objections:

1) It’s impossible to falsify your argument.

“The most decisive way to falsify our argument as a whole would be to find a distant and very different environment that, while quite hostile to life, nevertheless offers a superior platform for making as many diverse scientific discoveries as does our local environment.. The opposite of this would have the same effect- finding an extremely habitable and inhabited place that was a lousy platform for observation.”

2) It’s inevitable. Whatever environment we found ourselves in, we would find examples conducive to its measurability.

“…we are able to compare the measurability of our environment with that of other environment. For the discoveries we have made, we can reflect on the conditions necessary for such discoveries, and then compare those conditions with conditions in other settings. For instance, it’s unquestionable that a relatively transparent atmosphere is more conducive to astronomical curiosity and discovery than is a murky (translucent) or opaque one. We know that, at least in our Solar System, such an atmosphere is rare.”

3) Well, then, it’s just a selection effect of a different sort. There are phenomena we cannot observe and measure. The argument is biased toward measurable phenomena.

“Contrary to the claims of the anti-realist, who doubts the existence of external truth, scientists aren’t locked in a Kantian box where everything we perceive in the universe is primarily the product of our perception. There are many things we have difficulty measuring, and we realize that fact. For instance, we can’t determine the distance and properties of some astronomical objects. But we know they exist, since we can detect them either directly or indirectly, and we know that we don’t know their distances or many of their intrinsic properties. We can compare the objects in this category with the objects we can both detect and measure, and make generalizations about our ability to measure generally.
Similarly, we are not so bereft of imagination that we can conceive only of those things we directly perceive. If nature is regular in its operation, which we have every reason to believe, then we have some justification for extrapolating what we don’t see from what we do see. Theory often predicts the existence of certain objects prior to their discovery, such as additional planets, white dwarfs, black holes, the cosmic background radiation, and neutrinos. For fairly secure theories, we can imagine what conditions would allow us to detect such objects. We can then determine whether our environment allows us to do so and compare it with other settings in the universe. And this has happened numerous times in the past. It is striking how often physicists are able to detect entities that are initially predicted for theoretical reasons.”

4) You’re cherry-picking. You have used a biased sample to argue for correlation.

“This is always a danger with any general hypothesis like the one we’re proposing. When a theorist is looking over a large body of data, it’s always possible that he will pick out the pieces that form an intriguing pattern and ignore the pieces that don’t. As a result, when the data are considered in their entirety, the pattern dissolves. Any argument involving many different scientific disciplines is especially susceptible to such a danger, since it’s impossible to consider every piece of relevant data.
For this reason, we have intentionally chosen important examples from each of the scientific disciplines we’ve considered. We haven’t chosen obscure experiments or conditions of measurability that have little importance for science. For instance, it’s difficult to overestimate the importance of a transparent atmosphere and visible stars for astronomy, or sedimentary processes for geology. Any astrophysicist would admit the historical importance of perfect solar eclipses in the development of stellar physics. No cosmologist would deny the importance of detecting redshift of distant galaxies, or the cosmic background radiation for our knowledge of the history of the universe. Moreover, as we noted in the previous chapter, other scientists have noticed evidence of the correlation, although none have developed the argument as we have. This makes it less likely that we’re creating the correlation out of thin air.
This is an important objection nevertheless, because it would be one way to falsify the claim that there is a correlation between habitability and measurability. If our hypothesis is correct, the correlation will continue to be confirmed not only in areas we have considered but also in areas we haven’t considered. We are convinced that there are still many important discoveries awaiting us- some we can anticipate, some we cannot. At the risk of being wrong, we would be willing to predict that an identifiable subset of gamma ray bursts will one day be found to be useful standard candles. The only reason we have for predicting this is that if the correlation is real, gamma ray bursts would be prime candidates for helping us measure the universe. Perhaps they will allow tomorrow’s astronomers to probe even greater redshifts than we can with Type Ia supernovae today.
Another such prediction concerns evidence of early life. As we mentioned in Chapter Three, Earth’s geophysical processes have erased much of the early history of life. If measurability and discoverability are optimized from our vantage point, however, then we might expect that such information will be preserved somewhere accessible to us. The origin of life is a particularly important question. It would be surprising, assuming the correlation, if it could not be investigated. In fact, we might predict that such evidence is available somewhere, if we search diligently enough. It was precisely this prediction that led one of us (Guillermo) to consider the value of lunar exploration for uncovering relatively well-preserved relics of Earthly life from this early period. Finally, we’re willing to predict that since carbon and oxygen appear so often among our examples of measurability, they will be central characters in future discoveries as well.
Of course, if we’re right about these predictions, this would not prove our position but only further support it. If we’re wrong, conversely, it would not destroy our argument but would put a dent in it. But clearly our argument has a predictive dimension. In contrast, the Copernican and Anthropic Principles in their most unrestrained manifestations seem much less useful. Positing the existence of multiple universes, for instance, doesn’t offer many fecund research programs within our universe. It looks designed primarily to foreclose certain unwelcome metaphysical possibilities.”



5) Your argument is too speculative. It is based on guesses and a thin empirical base.

“Most of the examples we have selected are based on well-understood phenomena, and they are founded on abundant empirical evidence. Examples include the properties of our atmosphere, solar eclipses, sedimentation processes, tectonic processes, the characteristics of the planets in the Solar System, stellar spectra, stellar structure, and our place in the Milky Way galaxy. Some of our other examples have a weaker empirical base, because of the rapid acquisition of knowledge in certain fields. This new knowledge includes extrasolar planets, additional requirements for habitability, and a host of insights in the field of cosmology. But even in these examples our arguments have a reasonable theoretical basis.
Where our discussions are speculative, we have identified them as such. Thus, our discussion of the Circumstellar Habitable Zone, and all the factors that go into defining it, contain speculative elements, as does our discussion of the Galactic Habitable Zone. While we can’t yet estimate the precise boundaries of these habitable zones, present published studies are almost certainly missing many relevant factors, which, when eventually included, will reduce their sizes, and strengthen our argument. Notice, again, we are going out on a limb here and making predictions, which makes our argument vulnerable to future discoveries.”



6) Your argument is too subjective. It lacks the quantitative precision necessary to make a convincing case.



7) How can you have a correlation with a sample size of one?

“While it is true that Earth is the only example we have of a habitable planet, this does not prevent us from finding a correlation between habitability and measurability. First, our argument is not based merely on the particulars of our home planet and the life we know about. We have argued that life in the universe will almost surely resemble life on Earth, at least at the biochemical level, and a planet very much like ours is probably required for technological life. Starting with these basics, we have used knowledge from a broad range of disciplines to consider a broad range of environments. Discovering a correlation between habitability and measurability, then, is based on our knowledge, not our ignorance.
For example, with knowledge of stellar astrophysics and climatology, we cab ask whether a planet around an M dwarf is more or less habitable and offers more or less opportunity for discovery than Earth. Similarly, with our knowledge of galactic astronomy, we can ask how position in the Milky Way affects habitability and the measurability of the local and distant universe.”

And while Earth is the only habitable planet there are 9 planets and many moons that we can use for local comparisons

8) Since life needs complexity, the correlation is trivial. The greater the complexity, the greater the chance for a correlation between habitability and measurability.

9) There may be separate pathways significantly different from ours leading to equally habitable environments.

10) Your argument is bad for science because it encourages skepticism about cosmology.

11) General Relativity appears to be a superfluous law of nature, which is not obviously required for habitability. Yet it is an important part of science. Does this not contradict the correlation?

12) The correlation isn’t mystical or supernatural, since it’s the result of natural processes.

13) You haven’t really challenged naturalism. You’ve just challenged the idea that nature doesn’t exhibit purpose or design.

14) You haven’t shown that ETs don’t exist.

“This is true, but we did not intend to. In fact, ironically, design might even improve the possibility of ETs.”

Well, yeah…

Stars:

Total number estimated in the Milky Way- 100 billion
Over 80% are low-mass red dwarfs (most likely lack a habitable zone)
1-2% are massive short-lived blue giants
Only about 4% of the stars are early G-type, main-sequence stars like our Sun
50% of those are in binary systems
Then we have to consider what % of those are in the Galactic Habitable Zone

Earth-like planets:

We now know that our solar system is not typical
We do know other planets exist
At least 4% of Sun-like stars have giant planets at least as massive as Jupiter.

Then we have the factors required for a planet to host complex life-
Summary:

Within the Galactic Habitable Zone
Within the Circumstellar Habitable Zone
Liquid water
Orbit a Spectral type G2 dwarf main sequence star
Protected by gas giants
Nearly circular orbit-
Oxygen rich
Correct mass
Large moon to stabilize the angle of rotation
Moderate rate of rotation
Terrestrial planet
Ratio of water to continents
Plate tectonic re-cycling
Magnetic field
Both plate tectonics and the magnetic field require the core have enough heat to keep it liquid. The convection currents mix the minerals before recycling and also produce the required magnetic field as it flows around the iron inner core.
The Earth’s orbit is slightly elliptical. When the Earth is closest to the Sun (perigee) the southern hemisphere is enjoying summer, i.e. the Earth’s axis of rotation has the southern hemisphere at a better angle (than the northern hemisphere) towards the Sun for absorbing its vital rays. The Earth has the bulk of its continents in the northern hemisphere. Water stores the heat and then transfers it around the globe.