Absence of Evidence is not Evidence of Absence

The question of the likelihood of life elsewhere in the universe is a hot topic at the moment, and several people have mentioned this particular piece to me.

I will start my reflection by saying that I believe the existence of God is not a question that science can answer, so I am skeptical of any claim that science has proven or disproven the existence of God. Such claims are philosophical or theological arguments that interpret science, but cannot be considered science.
Scholars, at least to my knowledge, are not in agreement over how abundant life in the universe. Some believe that life is very rare, while others believe that there should be plenty of life elsewhere in the universe. There is also a distinction made between microbial life and intelligent life. It seems that more people are willing to accept that microbial life could exist other places. The criticism levied against those who hold that the universe is fertile often takes the form of the Fermi Paradox. In other words, if life is so prevalent in the universe, why have we been unable to find any evidence for it?

Fine tuning
The fine tuning argument presented in this piece is that the natural laws needed for life to exist are so specific, that the universe appears tailor-made for life, and therefore the universe must have been designed for life. It can be considered a statistical argument because proponents say that the odds of all of these things happening purely by chance is astronomically small, that therefore chance alone is not a valid hypothesis.
I do not claim to be an expert in these things, but my proximity to the science and theology dialogue in general has given me glimpses into the conversation. The author of this post quotes Paul Davies as saying that design appears likely. As far as I know, I do not believe that Paul Davies would consider himself a proponent of intelligent design, and while he might agree that SETI is not well served by looking beyond the planet for other life forms, he does advocate continuing the search. He proposes examining extreme conditions on earth to try and identify life that evolved in a way different than we currently know. I believe that he would say life has been able to evolve more than once, which the author of this piece is trying to argue against.

Theology Shaping Science
The author also says that Hoyle’s atheism was shaken by big bang cosmology. What it doesn’t mention, and what physicist and theologian Bob Russell speaks of frequently, is that Hoyle is a prime example of using a theological commitment to influence science. Because he felt that big bang cosmology supported the idea of Christian creation, he used the existing data at the time and constructed the steady state model of the universe, a model in which there was no time of origin. At the time that Bob Russell was working on his Ph.D., graduate students in physics had to choose which model to work with, and both equally fit the data. Bob uses this as an example of theology being a selection criterion between competing theories when competing theories are equally valid, scientifically speaking.

And this, I believe is what proponents of design are attempting to do. They are trying to say that based on the available data, it is just as reasonable, if not more reasonable, to argue that the universe was designed by some kind of intelligence. They are looking at the data and saying there is no evidence of life anywhere else in the universe and our understanding of what it takes to bring about life is much more complicated than when we started looking for life elsewhere.

Time: The universe is over 13 billion years old, life on Earth is at least 3.6 billion years old. Why did life take so long to evolve? Life as we know it requires certain elements, and those elements did not exist in the universe at first. It took at least a billion years for stars to create elements heavier than hydrogen, helium, and lithium. Multicellular life is only 1 billion years old and modern humans are only 200,000 years old. We are an extremely young species, and while life could have began elsewhere earlier, if the conditions are as specific as we believe, the conditions might be met later elsewhere. We’ve been looking for life elsewhere in the universe since roughly 1960 – less than 60 years. Kepler has been trying to identify exoplanets for 5 years and scientists interpreting the data from the close to 1000 verified exoplanets believe that they could number in the billions. The alternative is that time on a cosmic scale doesn’t rule out life elsewhere yet.

Extinct: It is possible that intelligent life did evolve elsewhere but they have gone extinct. The Kardashev scale hypothesizes the kinds of energy that technological civilizations could use. It is possible that in trying to harness energy, or through warfare, natural disasters, etc. other intelligent species have gone extinct. The problem is that there is no evidence of technology in the universe either.

Hiding: Another thought is that there are many intelligent species in the universe, but there are dangers that lead intelligent life to hide their existence from other intelligent life. Stephen Hawking has said that humans should not seeking out intelligent life elsewhere in the universe because they could pose a threat to humans and Earth.

Different kind of life: As the op ed piece makes clear, our understanding of what it takes to have life as we know it exist has expanded and complexified. This is not to say, however, that other kinds of life could exist.

This list is not meant to be exhaustive, but merely to suggest alternatives to the design hypothesis.

Theological Implications
Since it could be its own subject of inquiry I will limit my remarks, but I do think that the prevalence of life in the universe has theological implications. This post is already far longer than I anticipated so I will present only two questions:

If the universe is designed for life, why is life only found on one planet?

I believe that some would see this as emphasizing how important God views humans, and it certainly makes our species appear to be the telos of creation. On the other hand, I believe that some would find it puzzling that a God who desires to be in relationship with creation would create so much that is unable to conceive or relate to God (I’m sidestepping the whole question regarding other species on earth, that’s a whole other issue).

If the universe is designed for life, and Earth is the only place life exists, why will life on Earth cease to exist in five billion years?

The sun will eventually become a red giant star and this expansion would envelop Earth. Now most people believe this will not be an issue whatsoever for a variety of reasons, whether it be the destruction of the planet, space colonization, or the second coming. But it does raise the question often posed to proponents of design. That of optimal design. If the intelligence is God and God is all powerful, why would God choose to create life in this way? Surely God could have devised conditions for life that did not necessitate the destruction of the only planet where life exists.

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