Readings:“Life in Space: Astrobiology for Everyone” by Lucas Mix, Chapter 5: The anthropic principle
“Science & Religion: An Introduction” by Alister McGrath, pg 182-183: “fine-tuned” constants
Chapter 5 of “Life in Space: Astrobiology for Everyone” is entitled “Well-Behaved Observers?” The question mark in the title is vastly important because it enforces the idea that sometimes we are not well behaved when we observe the universe. In fact, our observations can be biased in different ways, many of which we are often unaware. However, by identifying and acknowledging some of these biases we can attempt to make more impartial observations. Two biases often present in human observations are the anthropic principle and the goldilocks principle.
THE ANTHROPIC PRINCIPLE
The first half of the anthropic principle is that any observation requires an observer, in this case, a human observer. In another world, perhaps the observer is non-human. In either case, any observation will be based on limited data, thus there exists a strong sampling bias.
The other half relates directly to humans and is a question of necesssity vs. contingency. “If we are necessary then the universe must be set up with us in mind. If we are contingent, then we represent one outcome among many…” (pg 60, Life in Space).
With this in mind, we can consider three forms of the anthropic principle.
“Weak” anthropic principle – it would be impossible to observe a universe where carbon-based life could not occur.
“Strong” anthropic principle – the structure of the universe and the value of physical constants make life inevitable.
“Final” anthropic principle – in the universe, intelligent life must occur and will never end.
A note on physical constants:
Many physical constants seem to be at exactly the right value for intelligent life in a stable universe. As stated by B. J. Carr and M. J. Rees in their 1979 Nature article, “the possibility of life as we know it evolving in the Universe depends on the values of a few physical constants – and is in some respects remarkably sensitive to their numerical values.”
From physics we know that there are four fundamental forces – the strong nuclear force, the weak nuclear force, electromagnetism and gravity. If only two of these differed by a mere 2%, the universe would not contain solid matter. For instance, if the strong nuclear force were slightly weaker, hydrogen would be the only element in the universe and carbon-based life forms would never occur. If the strong nuclear force were slightly stronger, all hydrogen would be converted into helium and other larger elements and long-lived stars could never be formed. If the weak nuclear force were slightly weaker, no hydrogen could have formed and if this force were slightly stronger than heavier elements necessary for life would never be ejected from supernovae. If the electromagnetic fine structure constant were slightly larger, stars would not be warm enough to heat planets to a life-sustaining temperature. If smaller, stars would have burned out too quickly for life to evolve. Finally, if the gravitational fine structure constant were slightly weaker, stars and planets would not have formed from their constituent coalescing materials. If gravity were any stronger, stars would have burned out too quickly to allow life to evolve.
In biology, intricate processes such as information storage, photosynthesis and cellular replication could not occur without a fine-tuned balance between energy usage and protein interactions. In this case, evolution gives us an idea of how the fine-tuning might occur. In physics, fine-tuning is not as easily explained, and demands a more philosophical treatment. A possible explanation comes from the ‘many-worlds’ idea, where there are an infinite number of parallel universes of which we experience only one. The one we experience is the one in which we exist, a clear example of the sampling bias intrinsic to the anthropic principle. Unfortunately, we have no way of proving or disproving the many-worlds interpretation because we have no way of observing any of the other parallel universes.
Contrary to the many-worlds interpretation, many proponents of intelligent design argue that the fine-tuning of the universe could only occur at the hand of a fine-tuner, an intelligent designer. Similar to the many-worlds interpretation, however, this cannot be either proved or disproved. In either case, our limited perspective impedes our ability to see the whole picture.
On seeing the whole picture
We discussed two different scenarios for the different views of science and religion in their interpretation of the universe. The first consists of blind monks (science and religion) trying to describe an elephant (the ‘true’ universe). One monk, touching the elephant’s tusk says, “An elephant is a tusk.” Another, touching the elephant’s leg says, “No, an elephant is a leg.” And a third monk, touching the elephant’s tail says, “You are both wrong, an elephant is a tail.” None of them is truly right or wrong; they all describe part of the whole, much like science and religion view different aspects of the universe.
Another similar interpretation is of two underground viewing stations of a whale in an aquarium. A person at one station sees part of the whale, obscured by the defects in their particular piece of glass. The other sees another part of the whale, obscured by different defects in the second sheet of glass. Both are seeing a portion of reality, which is obscured by individual observation biases.
It is interesting that in both examples, the representative of the “whole/true” universe is a large mammal, perhaps another example of the anthropic bias present in human interpretations of the universe.
The Fine-Tuning Observer
Another possible explanation to the problem of perceived fine-tuning is that it is the observer doing the tuning. Much like a radio signal coming in at all frequencies; the listener has the ability to tune the radio so that it produces the audio signal that is most clear to the listener. In much the same way, the universe may not adhere to any fine-tuned laws, but in order for a human observer to make sense of it, we make simplifying assumptions that impose fine-tuning an untuned universe.
Probability to the rescue
Probability provides a happy medium between a fine-tuned universe and a fine-tuning observer. While most observers would like to claim that they observe reality, acknowledging our biases prohibits a purely realist perspective. Instead we can say that universe is uncertain, but most of the time it operates according to rules we assume to be true. Probability is a way to quantify the limits of our knowledge. We can express our confidence in our observations, laws and theories of life without claiming that we ‘KNOW’ something is true. Bayesian inference provides a step-by-step process for fine-tuning our assumptions about the universe, just as evolution provides a step-by-step mechanism for the fine-tuning of biological processes. For a more complete discussion of probability, see the blog for meeting 9.
THE GOLDILOCKS PRINCIPLE
One of the greatest biases of human nature is to favor the familiar. Just as Goldilocks tried the small bed and the large bed before deciding that the medium bed was ‘just right,’ we often normalize our position relative to all other positions. We like to think that we are right and normal. Biologists tend to define life by the evolutionary and biochemical processes we find most familiar. However, different processes may shape life on different planets, so in the search for alternate life forms we must remember that we are possibly, in fact probably, not normal.
Extremophiles are observable examples of this principle. They survive at different pressure, temperature and salinity than most of the rest of life on Earth. Relative to humans, they are abnormal, but many scientists believe that they may have been the first life forms on Earth as the planet’s early climate was quite different that it is today. If that is the case then there it is much more likely that extremophiles are normal and we are the abnormal ones.
Idols of the Mind
Francis Bacon proposed the “Idols of the Mind” as obstructions on the path to proper scientific reasoning. There are four idols.
- Idols of the Tribe (Idola Tribus): This is humans’ tendency to perceive more order and regularity in systems than truly exists, and is due to people following their preconceived ideas about things.
- Idols of the Cave (Idola Specus): This is due to individuals’ personal weaknesses in reasoning due to particular personalities, likes and dislikes.
- Idols of the Marketplace (Idola Fori): This is due to confusions in the use of language and taking some words in science to have a different meaning than their common usage.
- Idols of the Theatre: This is the following of academic dogma and not asking questions about the world.
We ended with a return to our discussion of necessary and contingent and discussed how these relate to questions in cosmology and evolutionary biology. While there was some debate as to where certain questions lie, a general consensus divided questions into those pertaining to initial conditions, such as ‘why is anything here?’ (cosmology) or ‘why is there life?’ (evolutionary biology) versus those pertaining to contingent history, such as ‘why are there spiral bar galaxies?’ (cosmology) or ‘why is there intelligence?’ (evolutionary biology).
Finally, we decided on a more appropriate definition of the word “necessary” as it relates to our discussions. Because the universe is so well set up for us functionally, then it must also be set up for us teleologically and thus, the universe must necessarily be set up with us in mind. From this logic we decided that “necessary” really means “unavoidable” or “essential.”
Blog post contributed by J.L.
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