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Is Life From Outer Space a Viable Science Hypothesis?

Currently, panspermia has been rated as “plausible but not convincing.” Marks, Hössjer, and Diaz discuss the issues

Walter Bradley Center director Robert J. Marks has been doing a series of podcasts with Swedish mathematician Ola Hössjer, and Colombian biostatistician Daniel Díaz in connection with a recent co-authored paper on the fine-tuning of the universe for life in the Journal of Cosmology and Astroparticle Physics. In the first portion of this episode, podcast 153, “Why is there fine-tuning everywhere?” they look at one explanation offered for that fact in recent decades: panspermia (life was seeded throughout the universe) by advanced extraterrestrial beings. Prominent scientists who were atheists gave the theory the needed push. What is the science support for it?

This portion begins at 01:53 min. (The simulation theory portion begins at 4:59 min). A partial transcript, Show Notes, and Additional Resources follow.

Robert J. Marks: Everybody agrees — the scientists, the biologists, and the chemists. But why is the universe finely tuned? We have two guests with expertise in fine-tuning to talk with us today. Dr. Ola Hössjer is a professor of mathematical statistics at Stockholm University in Sweden. Our second guest is Dr. Daniel Diaz. He’s a research assistant professor of biostatistics at the University of Miami.

Robert J. Marks: I think I’ve done a good exhaustive search of the theories for fine-tuning. And the first one, Daniel, I’d like you to talk about is Panspermia. We’re fine-tuned because of Panspermia.

Daniel Díaz: Panspermia is the idea that life was seeded on earth from outer space. Then, there is a particularization of that idea that is called directed panspermia. It was, if I’m not mistaken, proposed by Francis Crick, the discoverer of the structure of the DNA molecule in order to explain how life started here on earth. It was the idea that it was seeded on earth by an extraterrestrial civilization.

Robert J. Marks: That’s really strange. What’s the difference between directed and regular panspermia? I think one was done on purpose. The other was accidental. Is that right?

Daniel Díaz: Yeah. Basically, there was an extraterrestrial agent in directed panspermia seeding life here on earth. On the other side, it could be simply accidental that life was seeded on earth, because it was coming, for instance, from an asteroid. And the little unicellular form of life started to develop until we come to this point.

Note: Double helix discoverer Francis Crick (1916–2004) was an atheist who recognized that the irreducible complexity of life called for an explanation that went beyond successful random swishes of molecules. In 1973, along with origin of life researcher Leslie Orgel (1927–2007), he proposed directed panspermia:

“It now seems unlikely that extraterrestrial living organisms could have reached the earth either as spores driven by the radiation pressure from another star or as living organisms imbedded in a meteorite. As an alternative to these nineteenth-century mechanisms, we have considered Directed Panspermia, the theory that organisms were deliberately transmitted to the earth by intelligent beings on another planet. We conclude that it is possible that life reached the earth in this way, but that the scientific evidence is inadequate at the present time to say anything about the probability. We draw attention to the kinds of evidence that might throw additional light on the topic.” – ScienceDirect

They originally proposed the idea “at a conference on Communication with Extraterrestrial Intelligence, organized by Carl Sagan and held at the Byuraka Observatory in Soviet Armenia in 1971. This theory which they described as an “highly unorthodox proposal” and “bold speculation” was presented as a plausible scientific hypothesis. Two years after the conference they published an article in Icarus on 1973.” Scientific American (2013) Science writer David Darling notes one of hteir key arguments: “The universality of the [genetic] code follows naturally from an “infective” theory of the origin of life. Life on Earth would represent a clone derived from a single set of organisms.” Crick later wrote a book about directed panspermia called Life Itself (1982)

Robert J. Marks: Another person that was into and believed about panspermia was Fred Hoyle. Hoyle definitely believed in a fine-tuned universe.

Isn’t the idea of panspermia just kicking the can down the road? It’s just kind of displacing the problem of where we came from to, “Where did this incredible civilization come from?” The planet life here on earth.

Daniel Díaz: Recently, there was a debate, a conversation between Sabine Hossenfelder, a very famous physicist with well-known channel on YouTube and Luke Barnes, who has done extensive research on fine-tuning.

They coincide in explaining why fine-tuning is actually not a scientific question. So Luke Barnes said that basically science ends saying that there is fine-tuning. Of course, different world views are going to produce different explanations for that fine-tuning that we are observing in nature.

Here’s a video debate between Sabine Hossenfelder and Luke Barnes. (2021). Also available as a podcast.

Robert J. Marks: Interesting. Panspermia, again, kicks the can down the road. It leads the question as to the origin of this master people that came here and planted life on earth. It’s just strange.

Note: Astronomer Fred Hoyle (1915–2001) was, like Francis Crick, an atheist — well, mostly. His doubts about atheism derived from the complexity of life compared to the known effects of merely random movements. He and Chandra Wickramasinghe (1939– ) appear to have made the theory discussable in science: “Fred Hoyle’s involvement in panspermia, recasting an ancient idea in a modern scientific framework marks an important turning point in the fortunes of this theory. Panspermia is discussed nowadays as a serious alternative to a purely terrestrial origin of life.” – Panspermia according to Hoyle (2003)

“One of the reasons for adopting panspermia, he [Wickramasinghe] explains, is the ‘superastronomically improbable transition from non-life to life’. The idea that abiogenesis occurred on the cosmically insignificant earth in an awkwardly short amount of time strikes him as improbable, at best.” – Cosmos (2018) The idea of directed panspermia is very much alive. A 2018 open access paper in Progress in Biophysics and Molecular Biology by 33 scientists from a range of disciplines argues for panspermia: “Cause of Cambrian Explosion – Terrestrial or Cosmic?”, citing Crick and Orgel and Hoyle, among others.

At this point, the evidence for panspermia has been rated “plausible, but not convincing” because there is no plausible, purely natural, explanation for life on Earth that would make panspermia unnecessary. That probably accounts for the interest of well-known atheists and near atheists.

Here’s PBS on the topic:

Next: Could advanced aliens have fine-tuned Earth for life?

Here are all of the instalments, in order, of the discussion between Robert J. Marks, Ola Hössjer, and Daniel Díaz on the fine tuning of the universe for life:

The first episode:

Ours is a finely tuned — and No Free Lunch — universe. Mathematician Ola Hössjer and biostatistician Daniel Díaz explain to Walter Bradley Center director Robert J. Marks why nature works so seamlessly. A “life-permitting interval” makes it all possible — but is that really an accident?


Fine-tuning? How Bayesian statistics could help break a deadlock: Bayesian statistics are used, for example, in spam filter technology, identifying probable spam by examining vast masses of previous messages. The frequentist approach assesses the probability of future events but the Bayesian approach assesses the probability of events that have already occurred.

The second episode:

Life is so wonderfully finely tuned that it’s frightening. A mathematician who uses statistical methods to model the fine tuning of molecular machines and systems in cells reflects… Every single cell is like a city that cannot function without a complex network of services that must all work together to maintain life.

Can there be a general theory for fine-tuning? If you make a bowl of alphabet soup and the letters arrange themselves and say, good morning, that is specified. What are the probabilities? Ola Hössjer sees the beauty of mathematics in the fact that seemingly unrelated features in cosmology and biology can be modeled using similar concepts.

The third episode

Was the universe created for life forms to live in? How would we know? We can begin by looking at the fundamental constants that underlie the universe. The constants of the universe — gravitational constant, entropy, and cosmological constant — must be finely tuned for life to exist.

Why did Stephen Hawking give up on a Theory of Everything? Daniel Díaz and Ola Hössjer continue their discussion of the fine tuning of the universal constants of nature with Robert J. Marks. The probability, they calculate, that the fine tuning of our universe is simply random is down to 10 to the minus sixty — a very small number.

The fourth and final episode

Is life from outer space a viable science hypothesis? Currently, panspermia has been rated as “plausible but not convincing.” Marks, Hössjer, and Diaz discuss the issues. Famous atheist scientists have favored panspermia because there is no plausible purely natural explanation for life on Earth that would make it unnecessary.

Could advanced aliens have fine-tuned Earth for life? That’s a surprisingly popular thesis, considering how hard it is to account for life without assuming a creator. As Robert Marks, Ola Hössjer, and Daniel Díaz discuss, some prominent atheists/agnostics have chosen to substitute advanced extraterrestrials for God.

Our universe survived a firing squad and it’s just an accident? According to the Weak Anthropic Principle, if things weren’t the way they are, we wouldn’t be here and that’s all there is to it. Given the odds, a philosopher likens the Weak Anthropic Principle to surviving a firing squad and concluding, incuriously, well… that’s just the way things are.

In an infinity of universes, countless ones are run by cats… Daniel Díaz notes that most of the talk about the multiverse started to appear once it was realized that there was fine-tuning in nature.
Robert J. Marks points out that even 10 to the 1000th power of universes would only permit 3,322 different paths. Infinity is required but unprovable.


If extraterrestrials didn’t fine tune Earth, maybe there is a God. In the face of a grab bag of ideas like creation by ETs or countless universes (some run by cats), why does the idea of a Creator seem far out? Traditional philosophers, not committed to a religion, have thought that deism (and theism) are rational, science-based conclusions, based on fine tuning.

You may also wish to read: No Free Lunches: Robert J. Marks: What the Big Bang teaches us about nothing. Bernoulli is right and Keynes is Wrong. Critics of Bernoulli don’t appreciate the definition of “knowing nothing.” The concept of “knowing nothing” can be tricky.

Show Notes

  • 00:33 | Introducing Dr. Daniel Díaz and Dr. Ola Hössjer
  • 01:53 | Panspermia
  • 04:59 | The Sims Theory
  • 10:40 | Anthropic Principle
  • 18:53 | Multiverse
  • 26:03 | The Creator Interpretation
  • 29:11 | Personal Beliefs
  • 36:24 | Final Words

Additional Resources

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Is Life From Outer Space a Viable Science Hypothesis?