By Will Barlow
What is fine-tuning?
Fine-tuning is the idea that the existence of life on Earth is due to remarkably precise “settings” in the natural world.
• Example: baking a cake vs. baking a “fine-tuned” cake
• Example: Finding a watch in a forest
Fine-tuning in Scripture
Romans 1:20 For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse.
Categories of fine-tuning
• Properties of carbon and water
• Beauty in math, physics, and nature
Example One: The Balance between forces
• A 1% change in the strong nuclear force would have a 30-1,000 fold impact on oxygen and carbon production in stars
• Small changes to gravity would make large life impossible
• The balance between gravity and electromagnetism allows for gentler yellow stars like our Sun
“The expansion speed, the material content of the universe, and the strengths of the basic forces, seem to have been a prerequisite for the emergence of the hospitable cosmic habitat in which we live.”
-Martin Rees, physicist and skeptic
Example Two: The Balance between other quantities
• The proportion of hydrogen converted to helium
• Nuclear physics is precisely designed to produce enough carbon to support life
• The existence of supernovas lead to second and third generation stars capable of supporting life
• A specific variable, called the “phase-space volume” appears to be fine-tuned to one part in 10,000,000,000^123 (1 followed by 10^123 zeros)
• The expansion rate of the Universe is perfect for life
• The amount of dark energy appears to be fine-tuned to 1 part in 10^120
Example Three: Earth’s place in the Universe
• The size of the Earth is perfect to support life
• The moon supports the Earth’s axial tilt, which makes Earth’s climate stable
• The moon runs the tides, which help moderate the climate
• The moon protects the Earth from asteroid strikes, comets, etc.
• The Sun is the right kind of star to support life
• The Earth is in the right “zone” in its orbit around the Sun to support life
Properties of carbon and water
Example One: Carbon
• Carbon forms stable compounds - is the only element able to produce DNA and RNA
• Carbon can store more genetic information than any other element
Example Two: Water
• Universal solvent
• Frozen water less dense than liquid water, which preserves life in ponds and makes the water cycle more efficient
• The water cycle allows water to moderate the temperature of landlocked regions
• High latent heat allows small bodies of water to exist and support life
• Surface tension allows for water skiing (and more importantly, for capillary action)
Beauty in math, physics, and nature
• F = m * a
• E = m * c^2
• F = (G * m1 * m2) / r^2
Why are these elegant equations true?
Beauty in math, physics, and nature
A powerful example: Eclipses
• The apparent size of the moon and the apparent size of the Sun are essentially identical!
• There is no reason why this must be the case
• Beauty and discovery
The existence of God
How do atheists respond to fine-tuning?
• Richard Dawkins uses the WAP (weak anthropic principle)
• Basically, WAP asserts that we would not be here to marvel the fine-tuning of the Universe, unless the Universe existed as it did.
"In essence, the weak anthropic principle wrongly asserts that the statement of a necessary condition of an event eliminates the need for a causal explanation of that event. Oxygen is a necessary condition of fire, but saying so does not provide a causal explanation of the San Francisco fire. Similarly, the fine tuning of the physical constants of the universe is a necessary condition for the existence of life, but that does not explain, or eliminate the need to explain, the origin of fine tuning.”
• Victor Stenger attacks fine-tuning several ways
• He argues that carbon (for example) is a natural consequence of the scientific order
• He also says that the Universe is mostly uninhabitable - maybe not as fine-tuned as we thought!
How to respond to Stenger?
• Carbon still came from nuclear reactions as given by the conditions of the laws of physics we have - it could have been different
• The Universe is not a waste of space - tells the story of God and is a place for us to explore
Three further objections to fine-tuning:
• Observational Selection Effect
• Problems with Probability
• Naturalistic Explanations
What does fine-tuning say about the existence of God?
I believe that the Universe was fine-tuned for life.
While this is not direct evidence for God, I think the existence of God fits the evidence far better than any other option.