Which is more rational? God is real or imaginary?

[otseng]

Proposition: God is a real actual thing, not something merely imagined or written about. God is intelligent and has intentionally created the universe.

Otseng will argue that belief in the truth of the above proposition is more rational than disbelieving it. McCulloch will argue that disbelieving the truth of the proposition is more rational than believing it.

[McCulloch]

According to Brownlee and Ward, the odds of any other planet existing to support life would be quite rare. Their Rare Earth hypothesis lists requirements for a hospitable planet. One criteria is being in a "Goldilocks zone". Others include being a rocky planet, having necessary elements (carbon, oxygen, etc) for life, have a moon, have plate tectonics, a correct tilt, et al. They do not calculate a specific number for the odds of such a planet existing, but they state "it appears that Earth indeed may be extraordinary rare."

In Rare Earth, the authors present the theories they favor as complete and widely accepted, masking the fact that many are controversial (for example, whether star metallicity is as rare as they describe and whether Cambrian Ediacarans represent additional extinct phyla). Furthermore, I spotted errors in my field of expertise (conflation of transcription and translation, a 20-fold exaggeration of the number of human genes -- both pertaining to the crucial concept of complexity) and a howler regarding the rotations of Mars and Venus (which are not locked, as the authors assert in their haste to make Earth unique in the solar system), These missteps make me wonder whether the authors misquoted additional facts instrumental to their hypothesis.

[...]

Calculating probabilities after the fact is equivalent to placing a bet after the race has been run. Conversations about the rarity of intelligent extraterrestrial life rest upon an enormous assumption which Ward and Brownlee, to their credit, mention once per chapter -- that life elsewhere will be life as we know it. Their oft-repeated statement that both Earth and humans are unique is neither novel nor contested -- nor helpful in predicting life elsewhere. Given our current almost total lack of knowledge, such books serve as reviews of existing evidence and as mirrors of the philosophical preferences of their authors; as such, they quickly become obsolete. Theorizing will never substitute for observation and experimentation. As for life elsewhere, Hamlet said it best -- and our universe, with its quirkiness, backs him up:

• There are more things in Heaven and earth, Horatio,
  Than are dreamt of in your philosophy.

Athena Andreadis graduated magna cum laude from Harvard. She holds a PhD in Molecular Biology from MIT, is Assistant Professor of Neurology at Harvard Medical School.

Two important things should be noted about this book. First, about what it does not contain: although I am sure many people will see the Rare Earth Hypothesis as another proof for the existence of a god, this notion of a proof is completely unrelated to the authors' ideas. The hypothesis claims that the conditions for creating complex life are rare; but we know for a fact that at least in one case, all the required conditions were met. Additionally, anyone who insists on taking the ideas of this book as a proof for god's existence will also have to accept the authors' prepositions about the age of the universe, the age of planet Earth, and more importantly, the theory of evolution.

[...]

The theory's weakest point, however, is obvious. The authors admit (after 281 pages of discussion) that their base assumption was that every complex life-form would be similar in many ways to life on Earth: We assume in this book that animal life will be somehow Earth-like. We take the perhaps jingoistic stance that Earth-life is every-life, that lessons from Earth are not only guides but also rules. We assume that DNA is the only way, rather than only one way (p. 282).

I am willing to concede even with the weaknesses of the Rare Earth arguments, that advanced life forms may be incredibly rare. Maybe as rare as one in every million galaxies. It still proves nothing about God.

[otseng]

It is a good thing I don't make that claim.

Good in the sense that it would be hard to defend that aliens do exist.

But, since you do not make any claim at all regarding the existence of aliens, you likewise cannot strengthen any position. It would be like someone coming to the witness stand and saying, "I do not know if he killed her or not". That testimony would not strengthen or weaken either side's position.

Those devices are all from fiction. As far as we know, they all violate the fundamental laws of physics. It is like saying that there are no advanced forms of life because none of them can do magic.

Pretty much anything regarding intergalactic travel would be classified as science fiction from our perspective.

There are a few answers to the Fermi paradox that I can think of:

Yet, all these rest on extraterrestrials actually existing or could exist. If you do not claim that they do exist, then these explanations would not follow.

We have evidence that life came to be in the universe once. Is it reasonable to conclude that it only happened once, just because we don't see any of the others?

On this alone, we cannot argue for much. But, coupled with the fact that it is highly improbable for life to arise in the universe, it would be reasonable to conclude that we are alone.

And my point is that sometimes the aggregate of lots of random events appears to be an intentional process.

I would not describe air flow as an intentional process. An arrow travelling through air to hit a bullseye 100m away I would classify as being intentional.

This is denied by the example of anaerobic life forms, thought by biologists to be the oldest forms of life.

I've thought more about the Black smokers. I have not found any confirmation that it is in an anaerobic environment.

I am willing to concede even with the weaknesses of the Rare Earth arguments, that advanced life forms may be incredibly rare. Maybe as rare as one in every million galaxies. It still proves nothing about God.

This plus the fact that no evidence for aliens exist, then it is reasonable to conclude that we are special in the universe. This would then disprove the mediocrity and the Copernican principles. And an intelligent creator would be a better explanation than the alternatives.

[McCulloch]

It is a good thing I don't make that claim.

Good in the sense that it would be hard to defend that aliens do exist.

But, since you do not make any claim at all regarding the existence of aliens, you likewise cannot strengthen any position. It would be like someone coming to the witness stand and saying, "I do not know if he killed her or not". That testimony would not strengthen or weaken either side's position.

That would be the case if I made no claims at all. However, I do claim that the probability that life has developed somewhere else in the universe is closer to 1 than it is to zero. I further claim that it has no bearing on this debate. If I am wrong and the probability is non-zero, then that does not prove or disprove God.

Those devices are all from fiction. As far as we know, they all violate the fundamental laws of physics. It is like saying that there are no advanced forms of life because none of them can do magic.

Pretty much anything regarding intergalactic travel would be classified as science fiction from our perspective.

from our perspective is redundant. There are no other perspectives available to us. But it is not just science fiction, but a violation of the known laws of physics.

Otseng raised the Fermi paradox as if it somehow lends strength to his argument. However, the Fermi paradox has a number of valid answers that do not involve any deities, so I don't see how it strengthens his side.

On this alone, we cannot argue for much. But, coupled with the fact that it is highly improbable for life to arise in the universe, it would be reasonable to conclude that we are alone.

But we still have not established this alleged fact. What has been established is that it is highly improbable for life to arise in any particular place in the universe. Fallacious attempts have been made to show that the smallness of that probability overcomes the vastness of the universe. But it is not an established fact that life is highly improbable in the universe.

I would not describe air flow as an intentional process. An arrow travelling through air to hit a bullseye 100m away I would classify as being intentional.

Are you not begging the question? Life arose at least once in this universe, but we cannot assume that life was the intentional purpose. You are painting the bullseye after the arrow has landed.

I am willing to concede even with the weaknesses of the Rare Earth arguments, that advanced life forms may be incredibly rare. Maybe as rare as one in every million galaxies. It still proves nothing about God.

This plus the fact that no evidence for aliens exist, then it is reasonable to conclude that we are special in the universe.

No, that is not a reasonable conclusion.

This would then disprove the mediocrity and the Copernican principles. And an intelligent creator would be a better explanation than the alternatives.

Well, not according to even the proponents of the Rare Earth Hypothesis. Even if it threw over the mediocrity and Copernican principles, it does not overthrow science for supernaturalism.

[otseng]

However, I do claim that the probability that life has developed somewhere else in the universe is closer to 1 than it is to zero.

So, are you saying there is close to a 100% chance that extraterrestrials exist?

from our perspective is redundant. There are no other perspectives available to us. But it is not just science fiction, but a violation of the known laws of physics.

Certainly I would agree that those intergalactic travel methods would violate the laws of physics. And they would most likely remain as science fiction for all eternity.

The reason I put "from our perspective" is that if aliens did exist, and if they had superior technology to ours, then they could possibly have some sort of technology for fast space travel.

But, I don't think scientists are placing too much hope on actually being able to shake hands with an alien. The only way really that we'd be able to detect them is through analyzing (radio) signals that they would generate.

Otseng raised the Fermi paradox as if it somehow lends strength to his argument. However, the Fermi paradox has a number of valid answers that do not involve any deities, so I don't see how it strengthens his side.

Because a rational conclusion from the Fermi paradox is that we are alone.

What has been established is that it is highly improbable for life to arise in any particular place in the universe. Fallacious attempts have been made to show that the smallness of that probability overcomes the vastness of the universe. But it is not an established fact that life is highly improbable in the universe.

I've already presented one calculation of having a habitable planet with the odds at 10^-20 assuming 10²² planets in the universe. But having a habitable planet is just one factor. The other even more remote possibility is for life itself to arise from non-living matter by random processes. As a matter of fact, this would violate the law of biogenesis which would put the odds at zero.

"The principle stating that life arises from pre-existing life, not from nonliving material."
http://www.biology-online.org/dictionar ... biogenesis

You are painting the bullseye after the arrow has landed.

Actually, even if there were no life at all (including us) in the universe, it would still be finely-tuned for life to possibly exist. Thus, the bullseye was painted even before we got here.

Even if it threw over the mediocrity and Copernican principles, it does not overthrow science for supernaturalism.

The issue is comparing the explanations. What explanation do you have then if the mediocrity and the Copernican principles are proved false?

[McCulloch]

However, I do claim that the probability that life has developed somewhere else in the universe is closer to 1 than it is to zero.

So, are you saying there is close to a 100% chance that extraterrestrials exist?

No, I won't go any further than to guess that it is somewhere higher than 50% but less than 100%. That range is every probability closer to 1 than zero.

Certainly I would agree that those intergalactic travel methods would violate the laws of physics. And they would most likely remain as science fiction for all eternity.

Others might disagree, but I agree with you. Thus, we must both agree that if there is another highly developed civilization beyond the capacity for us to detect, due to the laws of physics, we will never detect them. Even within our own galaxy they might remain beyond detection, and how many galaxies are there?

The reason I put "from our perspective" is that if aliens did exist, and if they had superior technology to ours, then they could possibly have some sort of technology for fast space travel.

Not if they live in the same universe as us. They don't have a different set of laws of physics.

But, I don't think scientists are placing too much hope on actually being able to shake hands with an alien. The only way really that we'd be able to detect them is through analyzing (radio) signals that they would generate.

Making the grand assumption that they would use radio signals and that they would be distinguishable by us from white noise.

Otseng raised the Fermi paradox as if it somehow lends strength to his argument. However, the Fermi paradox has a number of valid answers that do not involve any deities, so I don't see how it strengthens his side.

Because a rational conclusion from the Fermi paradox is that we are alone.

Yes, the rational conclusion from the Fermi paradox is that we are alone in our corner of the universe. It stretches any rational interpretation of the Fermi paradox to extend that conclusion to the vast recesses of the universe which will be forever beyond our capacity to examine in any detail. The Fermi paradox would not be violated by, for example, advanced forms of life occurring with a distribution of about one per every thousand galaxies.

What has been established is that it is highly improbable for life to arise in any particular place in the universe. Fallacious attempts have been made to show that the smallness of that probability overcomes the vastness of the universe. But it is not an established fact that life is highly improbable in the universe.

I've already presented one calculation of having a habitable planet with the odds at 10^-20 assuming 10²² planets in the universe. But having a habitable planet is just one factor.

[addressed separately]

The other even more remote possibility is for life itself to arise from non-living matter by random processes.
As a matter of fact, this would violate the law of biogenesis which would put the odds at zero.

"The principle stating that life arises from pre-existing life, not from nonliving material."
http://www.biology-online.org/dictionar ... biogenesis

The spontaneous generation that Pasteur and others disproved was the idea that life forms such as mice, maggots, and bacteria can appear fully formed. They disproved only a form of creationism. There is no law of biogenesis saying that very primitive life cannot form from increasingly complex molecules. Creationists and Intelligent Design proponents describe the law of biogenesis as stating that life cannot come from non-life, it can only come from other life. This is a misunderstanding or misrepresentation of the law.

You are painting the bullseye after the arrow has landed.

Actually, even if there were no life at all (including us) in the universe, it would still be finely-tuned for life to possibly exist. Thus, the bullseye was painted even before we got here.

I found some mold on a grape in the refrigerator the other day. It was only on one grape, there was no other mold in the fridge, as far as I could tell. If I had set the temperature lower, it would not have occurred. If I had eaten all of the grapes, there would be no mold on the grape. Mold only grows when conditions are compatible for the growth of mold. The existence of mold on only one grape would lead any reasonable person to conclude that such a rare event must have been deliberately planned by the owner and manufacturer of the fridge. Clearly it was designed with the intent of providing a place for this one particular mold to grow. I am sure that you could not come to any other reasonable conclusion. Right?

Even if it threw over the mediocrity and Copernican principles, it does not overthrow science for supernaturalism.

The issue is comparing the explanations. What explanation do you have then if the mediocrity and the Copernican principles are proved false?

Several of the laws of physics, those that seem the most universal and profound, are in fact little more than statements about the simplicity of nature that can almost go unsaid. The so-called laws of conservation have been shown to be statements about the homogeneity of space and time. The first law of thermodynamics, the conservation of energy, results from there being no unique moment in time. Conservation of momentum follows from the Copernican principle that there is no preferred position in space. Other conservation laws, such as charge and nucleon number, also arise from analogous assumptions of simplicity. A homogeneous universe, one with a high level of symmetry, is the simplest of all possible universes, just the kind we would expect to happen by accident. In such a universe, many conservation laws will automatically exist.

[with material from Talk Origins]

So, if you are suggesting that we abandon the mediocrity principle and the Copernican principle, then you are also suggesting that we abandon all of the laws of physics based on the assumption of a homogeneous universe.

I am happy to report, however, that we need not be that extreme simply because life is a rare perhaps even a unique event. Let's say that we have a homogeneous universe where the probability of life is exceedingly low. The simple fact that life shows up once does not change the fact that the universe is homogeneous.

[McCulloch]

Hugh Ross has given a ballpark guess at the necessary requirements for life to exist (not to mention the odds of life arising).

Galaxy type - .1
Star location - .2
Number of stars - .2
Star birth date - .2
Star age - .4
Star mass - .001
Star luminosity - .0001
Star color - .4
Supernova rates - .01
White dwarf rates - .05
Distance from star - .001
Inclination of orbit - .8
Axis tilt - .3
Rotation period - .1
Orbit eccentricity - .3
Surface gravity - .001
Tidal force - .1
Magnetic field - .01
Albedo - .1
Density - .1
Thickness of crust - .01
Oceans-to-continent ratio - .2
Asteroidal collision rate - .1
Atmospheric transparency - .01
Atmospheric pressure - .1
Atmospheric discharge rate - .1
Atmospheric temperature gradient - .01
Carbon dioxide level - .01
Oxygen quantity - .01
Ozone quantity - .01
Oxygen to nitrogen ratio - .1
Quantity of greenhouse gases - .01
Seismic activity - .1

Total probability: 10^-42

(Source: The Creator and the Cosmos, Hugh Ross, pg 134)

These values are quite conservatives estimates.

Please provide support for the following assertions:

1. Galaxy type only one in ten galaxies could support life
2. Star location In the galaxies that could support life, only one in five stars are located in a place where life could be supported.
3. Number of stars Explain what this number means and why it is one in five
4. Star birth date Of the stars selected by galaxy, location and number, only two in five are of a suitable star birth date for life support
5. Star age of the stars selected by the above factors, including star birth date, only two in five stars have a suitable age to support life
6. Star mass
   Of the stars selected above, only one in 1,000 have a suitable mass to support life
7. Star luminosity Of the stars otherwise selected, including suitable mass, only one in 10,000 have a suitable luminosity to support life
8. Star color of the stars with suitable luminosity and the other factors, only two out of five are the right color
9. Supernova rates of all the stars already selected, ninety nine out of one hundred will be unsuitable due to supernova rates.
10. White dwarf rates of the remaining stars, nineteen out of twenty cannot support life due to white dwarf rates
11. Distance from star Of the remaining stars, only one in one thousand will have a planet the correct distance from it
12. Inclination of orbit Of those planets, one fifth will have an inclination of orbit that is not suitable to supporting life.
13. Axis tilt Of the remaining planets, only 30% will have an axis tilt appropriate to life.
14. Rotation period of the remaining planets, only one in ten will have a day of the correct length of time for life.
15. Orbit eccentricity Of these planets, only 30% will have an orbit eccentricity appropriate to life.
16. Surface gravity of the the planets, otherwise acceptable, only one in one thousand will have the right amount of gravity at the surface.
17. Tidal force even with the correct gravity and everything else so far listed, only on in ten will have a correct level of tidal force to sustain life
18. Magnetic field The magnetic field for ninety nine out of one hundred planets otherwise suitable, would prevent the development of life.
19. Albedo I don't even know what this means. Please explain why it knocks out nine of the remaining ten possibilities
20. Density Please explain why the density removes nine of the ten remaining planets with the correct surface gravity and other features
21. Thickness of crust Of the otherwise suitable planets, only one in one hundred have a crust of an appropriate thickness to support life.
22. Oceans-to-continent ratio Four out of five otherwise suitable planets have either too few or too many oceans for life to have arisen.
23. Asteroidal collision rate nine out of ten otherwise suitable planets have too many asteroids hitting it.
24. Atmospheric transparency only one in one hundred otherwise suitable planets have the correct atmospheric transparency
25. Atmospheric pressure only one in ten otherwise suitable planets have the correct atmospheric pressure suitable to sustain life.
26. Atmospheric discharge rate only one in ten otherwise suitable planets have an atmospheric discharge rate suitable to support life
27. Atmospheric temperature gradient the atmospheric temperature gradient is out of order in ninety nine of one hundred otherwise suitable planets.
28. The Carbon dioxide level is right in only one in one hundred otherwise suitable planets
29. the Oxygen quantity is insufficient in ninety-nine of every remaining hundred planets
30. Even when the oxygen quantity is correct the Ozone quantity is toxic to life in ninety-nine of one hundred planets, otherwise suitable
31. the Oxygen to nitrogen ratio is appropriate for life in only one in one hundred planets that are otherwise suitable.
32. The Quantity of greenhouse gases rules out ninety-nine out of one hundred remaining possibilities.
33. And even if everything else is right nine out of ten will have too much Seismic activity
34. Total probability: 10^-42
    When I multiply these probabilities I get 9.216 10^-48. Can your guy even be trusted to do basic math? Allowing for rounding, the number has to be between 4.2 10^-43 and 1.6 10^-55.
35. Please show that these values are quite conservatives estimates.

You may, if you wish, choose to withdraw your claim as not being supportable. This is a very long list of unsupported assertions you have made for yourself. If you show that the top one third of the least likely are reasonable values and independent, I will graciously concede the others. Those would be

• Star luminosity .0001
• Star mass .001
• Distance from star .001
• Surface gravity .001

and any seven of the following (all listed at .01)

• Supernova rates
• Magnetic field
• Thickness of crust
• Atmospheric transparency
• Atmospheric temperature gradient
• Carbon dioxide level
• Oxygen quantity
• Ozone quantity
• Quantity of greenhouse gases

[otseng]

No, I won't go any further than to guess that it is somewhere higher than 50% but less than 100%. That range is every probability closer to 1 than zero.

So, you state that there is a greater than a 50% chance that extraterrestrials exist, even though there is no evidence for their existence, that they are also undetectable by us, and that it is acknowledged that advanced life is incredibly rare?

Others might disagree, but I agree with you. Thus, we must both agree that if there is another highly developed civilization beyond the capacity for us to detect, due to the laws of physics, we will never detect them. Even within our own galaxy they might remain beyond detection, and how many galaxies are there?

I'm not saying that they would be undetectable, but simply that we cannot visit them if they are in another galaxy. They would still be theoretically detectable by EMR signals.

Not if they live in the same universe as us. They don't have a different set of laws of physics.

I'm not saying they would have different laws of physics, but that they would have a different level of technology.

100 years ago, we didn't even have space travel technology. If another civilization is 1000 years more advanced than us, they would most likely have some sort of space travel technology that is better than our current methods of space travel.

Making the grand assumption that they would use radio signals and that they would be distinguishable by us from white noise.

And also making the assumption that they do actually exist.

It stretches any rational interpretation of the Fermi paradox to extend that conclusion to the vast recesses of the universe which will be forever beyond our capacity to examine in any detail. The Fermi paradox would not be violated by, for example, advanced forms of life occurring with a distribution of about one per every thousand galaxies.

There is no scientific evidence (either direct evidence or indirect evidence) that extraterrestrials exist, so it is well within rationality. It would go beyond empirical evidence to state that extraterrestrials in fact do exist.

The spontaneous generation that Pasteur and others disproved was the idea that life forms such as mice, maggots, and bacteria can appear fully formed.

The first cell would also have appeared fully formed from non-life.

There is no law of biogenesis saying that very primitive life cannot form from increasingly complex molecules.

It is similar to maggots forming from rotten meat, only the scale is smaller and it would be from soup instead of from meat. Just because the scale is smaller and the ingredients are different doesn't mean that the law does not apply.

What makes it a law is that we have not observed any exception to this law. We have never observed any life coming from non-life. Even at the microscopic level.

The existence of mold on only one grape would lead any reasonable person to conclude that such a rare event must have been deliberately planned by the owner and manufacturer of the fridge.

Refrigerators are not designed so that mold can grow on grapes.

So, if you are suggesting that we abandon the mediocrity principle and the Copernican principle, then you are also suggesting that we abandon all of the laws of physics based on the assumption of a homogeneous universe.

Depends on what you mean by homogeneous. If you mean that the laws of physics are the same in every part of the universe, I would agree with you. But, saying that the laws of physics apply everywhere does not prove the mediocrity or the Copernican principles are true.

To restate the principles:

"The assumptions of mediocrity principle is the notion in philosophy of science that there is nothing special about humans or the Earth."
http://en.wikipedia.org/wiki/Mediocrity_principle

"In physical cosmology, the Copernican principle, named after Nicolaus Copernicus, states that the Earth is not in a central, specially favored position. More recently, the principle has been generalized to the relativistic concept that humans are not privileged observers of the universe."
http://en.wikipedia.org/wiki/Copernican_principle

You may, if you wish, choose to withdraw your claim as not being supportable. This is a very long list of unsupported assertions you have made for yourself.

I did not make the assertion and I did not generate those values, but I simply provided what one cosmologist has proposed. Simply because I cannot justify his calculations does not mean it is inadmissable as evidence.

Whereas you have stated (without reference) that life is possible in one in a thousand/million galaxies. How do you justify those figures?

[McCulloch]

No, I won't go any further than to guess that it is somewhere higher than 50% but less than 100%. That range is every probability closer to 1 than zero.

So, you state that there is a greater than a 50% chance that extraterrestrials exist, even though there is no evidence for their existence, that they are also undetectable by us, and that it is acknowledged that advanced life is incredibly rare?

Yes. Any evidence that they exist, beyond the distance of our own galaxy (and even in some places within our galaxy) would be undetectable by us, so the lack of evidence is hardly an issue. The probability of advanced life is incredibly rare, but the size of the universe is incredibly vast. I am of the view that the vastness of the universe offsets the rareness of the event. You calculate that the rareness of the event offsets the vastness of the universe. I have asked for some validation of your calculation.

My reasoning is thus. Advanced life has occurred at least once. Given the vast size of the universe, there is no apparent reason why it should not have occurred again.

I'm not saying that they would be undetectable, but simply that we cannot visit them if they are in another galaxy. They would still be theoretically detectable by EMR signals.

Do you have any idea how far away some of those other galaxies are? A signal from some very distant galaxy, even if it did reach us (remember the universal speed limit) would be faint and perhaps indistinguishable from white noise.

I'm not saying they would have different laws of physics, but that they would have a different level of technology.

100 years ago, we didn't even have space travel technology. If another civilization is 1000 years more advanced than us, they would most likely have some sort of space travel technology that is better than our current methods of space travel.

Of course, in a thousand years we might have space travel that is much better than our current methods. Let's be wild in our speculation and imagine that they could travel at the fabulously unrealistic speed of half the speed of light, even though acceleration to that speed would be incredible and the relativistic effects significant. They would still only be able to explore a small corner of their own galaxy. The Whirlpool Galaxy is located at a distance of approximately 23 million light-years away. It has a radius of about 38,000 light-years. IOK-1 is a galaxy that is 12.88 gigalight-years away. Their inhabitants are not going to communicate with us any time soon.

There is no scientific evidence (either direct evidence or indirect evidence) that extraterrestrials exist, so it is well within rationality. It would go beyond empirical evidence to state that extraterrestrials in fact do exist.

And neither of us have stated that they do exist. You have stated that they do not exist, an assertion not supported by any evidence. I have stated that they might exist and have offered a very rough guess at the probability of their existence.

The first cell would also have appeared fully formed from non-life.

The first cell-like structures would have developed from non-cellular self-replicating molecules.

We have never observed any life coming from non-life.

No that part is still a mystery. We know that life did somehow come from non-life, since at one time there was no life and now there is. Scientists are searching for a naturalistic explanation. Some theists claim that such a search will forever be fruitless. One difficulty is that we have run into a small problem defining what is life.
Wiki: biological definition of Life
there is no unequivocal definition of life
[...]
some have proposed other biological definitions of life:
[...]
Viruses are most often considered replicators rather than forms of life. They have been described as "organisms at the edge of life", since they possess genes, evolve by natural selection, and replicate by creating multiple copies of themselves through self-assembly. However, viruses do not metabolise and require a host cell to make new products. Virus self-assembly within host cells has implications for the study of the origin of life, as it may support the hypothesis that life could have started as self-assembling organic molecules.

Refrigerators are not designed so that mold can grow on grapes.

The universe is not designed so that humans can grow on Earth. Thank you.

You may, if you wish, choose to withdraw your claim as not being supportable. This is a very long list of unsupported assertions you have made for yourself.

I did not make the assertion and I did not generate those values, but I simply provided what one cosmologist has proposed. Simply because I cannot justify his calculations does not mean it is inadmissable as evidence.

I have shown in more than one way that this creationist's calculations are flawed. Without addressing those flaws, his calculations cannot be admitted as evidence. How about you show that there is some level of consensus among cosmologists with regard to these calculations?

Whereas you have stated (without reference) that life is possible in one in a thousand/million galaxies. How do you justify those figures?

I have not.

I am willing to concede even with the weaknesses of the Rare Earth arguments, that advanced life forms may be incredibly rare. Maybe as rare as one in every million galaxies.

Here I state that I am willing to concede that life may be as rare as one in every million galaxies. However, I don't know how rare life is. You have not shown how rare life is. One occurrence in every million galaxies is incredibly rare, so it does agree with the evidence thus far presented. I am not willing to concede that it is lower than that very very rare level without some evidence. I wait for the evidence to be presented.

[McCulloch]

I've already presented one calculation of having a habitable planet with the odds at 10^-20 assuming 10²² planets in the universe.

There may be 1.710¹¹ galaxies in the observable universe.
And 410¹¹ stars in our galaxy.
Assuming our galaxy is typical, then there would be about 6.810²² stars in the universe. Are you assuming that stars on average have 0.15 planets? Our star has 8.

If the only a few numbers in your admittedly rough calculation are off significantly or a few of the assumptions are false, the expected number of advanced life forms in the universe would be significantly more than one.

[otseng]

Any evidence that they exist, beyond the distance of our own galaxy (and even in some places within our galaxy) would be undetectable by us, so the lack of evidence is hardly an issue.

Yet, it is always raised as an issue in regards to God. What I'm trying to point out is the inconsistent standards being applied to aliens and to a creator. If no evidence of aliens exist and they are completely undetectable, then it can still be assumed that they must exist. Yet, if no evidence for God exists and it is undetectable, then it is concluded it must not exist. And even when evidence is presented for God's existence and evidence is presented that the probability for alien life is quite low, it is still asserted that God does not exist and aliens do.

The probability of advanced life is incredibly rare, but the size of the universe is incredibly vast. I am of the view that the vastness of the universe offsets the rareness of the event. You calculate that the rareness of the event offsets the vastness of the universe. I have asked for some validation of your calculation.

Again, I did not generate the values, but if you insist, we can explore justifying the values. But, you first need to provide your calculation of the probability of having a habitable planet.

My reasoning is thus. Advanced life has occurred at least once. Given the vast size of the universe, there is no apparent reason why it should not have occurred again.

Since you have not yet provided any justification for the probability of having a habitable planet, it would be presumptuous to assume that the number of planets would overcome it.

Let's be wild in our speculation and imagine that they could travel at the fabulously unrealistic speed of half the speed of light, even though acceleration to that speed would be incredible and the relativistic effects significant.

I would agree that even going half the speed of light would not be realistic. To do intergalactic travel, it would require some unknown method that is not bound by the universal speed limit.

The first cell-like structures would have developed from non-cellular self-replicating molecules.

Is there any evidence of "cell-like structures developing from non-cellular self-replicating molecules"?

We have never observed any life coming from non-life.

No that part is still a mystery.

Then the law of biogenesis remains a law. And there is no exception to it.

We know that life did somehow come from non-life, since at one time there was no life and now there is. Scientists are searching for a naturalistic explanation. Some theists claim that such a search will forever be fruitless.

And scientists should continue to search for a naturalistic explanation. And if they do, my argument will be falsified. If they do not find a naturalistic explanation, my argument stands.

The universe is not designed so that humans can grow on Earth. Thank you.

I believe the universe was designed for humans to be on Earth. This can also be falsified. If another planet is found to be hospitable for humans, then the universe was not designed for humans to only be on Earth.

I have shown in more than one way that this creationist's calculations are flawed.

I as well have addressed those.

How about you show that there is some level of consensus among cosmologists with regard to these calculations?

I'm not stating it's a consensus figure. It's just one cosmologist's guesstimate.

However, I don't know how rare life is. You have not shown how rare life is.

From the evidence that we do have, there's just one. Here on Earth. So, based on verifiable evidence, life is rare and unique.

There may be 1.710¹¹ galaxies in the observable universe.
And 410¹¹ stars in our galaxy.
Assuming our galaxy is typical, then there would be about 6.810²² stars in the universe. Are you assuming that stars on average have 0.15 planets? Our star has 8.

The number of planets is the estimate provided by Hugh Ross, not myself.

But, let's say there are 10²⁴ planets in the universe, the odds would still be quite small at 10^-18.