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Questions tagged [anthropic-principle]

This can be used for the strong or weak anthropic principle. Please be sure to mention in your question which you are talking about.

There are two forms of the anthropic principle; however, the overall idea is the philosophical consideration that the Universe must be compatible with the sapient life that observes it. Some proponents of this principle say that this explains the age and fundamental physical constants necessary to accommodate conscious life.

Strong Anthropic Principle

Proponents of the strong anthropic principle state that this is the case because the universe is somehow compelled to have sapient, intelligent life emerge in it.

Weak Anthropic Principle

Some critics of the Strong Anthropic Principle argue in favor of the weak anthropic principle, which states that the universe's apparent fine-tuning is the result of selection bias (i.e., only in a universe capable of supporting intelligent life will there be intelligent beings able of reflecting on fine-tuning).

Most often these arguments draw on the supposed existence of some type of a multiverse for there to be a statistical population of universe so our selection bias (of only seeing this universe) can occur.

There is more information about the anthropic principle here.

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Why do universal constants have the values they do?

This is meant to be a generic question of the type that we get repeatedly on this site, in different versions: The origin of the value of speed of light The gravitational constant G theoretically? What if Planck's constant were smaller or bigger…
user4552
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Where does the $10^{500}$ estimate for the number of stringy vacua come from?

This number is thrown around a lot so I'd like to understand its origin. I know that it counts compactifications of string theories on (not only) Calabi-Yau manifolds and probably also some other ingredients. 1. What precisely are those ingredients…
Marek
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Earth still exists - does this fact tell us anything about LHC safety?

When LHC was about to be launched there were many fears that it would destroy the world. To counter them scientists tried to carefully examine all possibilities and concluded that there is nothing dangerous. While most of their arguments sounds fine…
user40492
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The measure problem in the anthropic principle

The anthropic principle is based upon Bayesian reasoning applied to the ensemble of universes, or parts thereof, conditioned upon the existence of conscious observers. That still leaves us with the problem of determining the prior probabilities.…
Greg
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Is it a coincidence that Big Bang nucleosynthesis lasted about one free neutron half-life?

The free neutron half-life is about 10 minutes. Big Bang nucleosynthesis, which mostly involves protons and neutrons interacting, lasted about 20 minutes. Question: Is it a coincidence that these are basically the same time scale? I'd be interested…
tcamps
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Why aren't we Boltzmann brains in an infinite universe?

Either space is finite or it is infinite. a) - If space is infinite in extent, either it is thermal over an infinite volume, or it is in the vacuum state for most of it. If it is thermal, infinity is a large place, and random statistical…
Mad scientist
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Are many-worlds and the multiverse really the same thing?

Are many-worlds and the multiverse really the same thing? Not too long ago, Susskind and Bousso uploaded the article "The Multiverse Interpretation of Quantum Mechanics" with the thesis that the many-worlds interpretation and the multiverse of…
Vincent
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Undergraduate-friendly reading material on the multiverse?

I'll be teaching a seminar for first-year undergraduates next year. The idea of my university's first-year seminar program is to expose students to exciting ideas and important texts in a somewhat interdisciplinary way. My course will focus on three…
Ted Bunn
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Can (or How) Anthropic Principle be made into a scientific theory?

Anthropic Principle says physical Universe must be compatible with the conscious life that observes it. I thought it is just philosophy mumbo-jumbo and it's not physics. But I could be wrong; I wonder whether is it possible to formulate it…
Graviton
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Is the muon superfluous?

When the muon was discovered, it was so unexpected that Rabi's reaction was, "What? Who ordered that?" The muon doesn't play any obvious role in the behavior of protons, neutrons, and electrons. Does the muon substantially affect the functioning of…
rob
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Fine Tuned Universe

Is the fine tuning that cosmologists talk about (that our Universe is fine tuned for intelligent life) is the same as the fine tuning of the squared mass parameter of the Higgs in the Standard Model? And that in SUSY models? Also, could anyone refer…
stupidity
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Is the only diffeomorphism invariant anthropic principle the final anthropic principle?

Quantum gravity is a gauge theory with the gauge symmetry spacetime diffeomorphisms. Presumably the quantum state of our universe is invariant under spacetime diffeomorphisms, including timelike diffeomorphisms. But I believe that these…
green pigs eat eggs
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Why do we need the anthropic principle?

I've read debates about the anthropic principle (strong, weak, take your pick) but do not understand why it is even a subject of discussion. What observation is it meant to explain? For example: does it explains why our universe has the fundamental…
pferrel
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A finer tuned universe

I was reading about the idea of the fine-tuned universe and the anthropic principle. It is stated how small changes in some of the physical constants would render life as we know it impossible. My question is to do with the opposite of this idea,…
sooggzz
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Do matrix models capture the string landscape?

Essentially what the title asks-- are matrix models, such as BFSS, believed to capture in any way the large possible space of false string vacua, for instance as saddles in the action with nonminimal energy, in such a way that the dynamics of…
Panopticon
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