Consider the anthropic principle in its most basic form: that the conditions of the universe must be that which allow for observers to exist. It's a truism by definition, if the universe couldn't harbour the kind of life observing it then there would be no observations of it. We know the universe can support us because we are here.
Various forms of fine-tuning are inevitably proposed to explain just why were are here. Certain types of fine-tuning can be explained already. For example, that we are so suited to the planet we live on can be explained by evolutionary theory. Or that the planet has a stable orbit and is the right distance from the sun can be explained by the huge number of planetary systems that there would be. etc. But there are some things that seem yet unexplained.
While there are non-controversial explanations for particular aspects, there are still aspects of nature which we don't understand. There is not yet a theory of everything, so it's no surprise to see a whole host of arguments based around seemingly improbable aspects of the universe. I think it's quite silly, because there are so many things critical to our existence it means that any any change means we don't exist.
I think the problem stems from our vantage point. We are looking at a universe 13.7 billion years old, we aren't seeing the process but the result. Like us being a result of 3.5 billion years of evolution, that evolution produced us does not mean that evolution was designed to produce us. Likewise, us existing in the universe does not mean the universe is the way it is for our existence.
I want to illustrate this using a thought experiment, invoking the principle of stability. Another truism, the principle can be stated as stable forms last longer than unstable forms. We can understand this function already in terms of stable and unstable isotopes. Nitrogen-14 is a stable atom, but when bombarded with cosmic rays in the atmosphere transforms into Carbon-14. Carbon-14 is an unstable form of carbon and decays back into the stable Nitrogen-14.
Imagine rolling a die 1000 times and recording the sequence. A simple procedure but one that will generate a sequence of immense improbability 1.4x10778. Each role has a 1 in 6 chance of being any value yet the number you end up with is beyond all human comprehension of improbability. It produced a huge number, one that wasn't by any means inevitable but it did result through the series of chance rolls. It's only a problem to explain if you're expecting the outcome to be a particular 1000 roll sequence. This is why instead of looking backwards we should look fowards and ask whether a process could allow for the possibility of our existence instead of looking for improbable things in order to invoke
If we go back far enough in time, we are going to do away with a lot of things. Life on this earth is but a few billion years old, our solar system only 4.6 billion years old. The heavy elements that we see in great amounts would eventually go to, for we know they are forged in stars and distributed by supernovae explosions. Eventually we get back before there's galaxy formation, to a universe where there's only light atoms (hydrogen, helium and a tiny bit of lithium) then before atoms can form, then before before there were particles like protons. Going back further we see elementary particles then back further a place before elementary particles where there were no fundamental forces.
Like the die experiment, look at the process going forward. It's not an aim to get what we have now, but to see what would happen if we took the process on the principle of stability. Stable things last longer than unstable things, so in the most unstable state imaginable, some form of structure should emerge. Consider this initial structural states as elementary particles. Now that there is a basic form of structure. With those particles interacting, there's always further possibility that bigger particles could be made. Not all interactions need to lead to bigger particles, but if only a small percentage of particles could form stable structures they should emerge on account of stable structures being more stable than unstable structures.
On the principle, this should continue until there are no more possible increments in complexity. So now we have a whole host of particles, some composites of many iterations of smaller particle collectives colliding, and some that are still elementary particles. Some of these particles may only be able to exist when the universe is energetic enough and should not be seen in the latter universe except through high-energy collisions. And some states of interactivity might not be able to happen until the universe is sufficiently cool enough to allow for them. Atoms might be a good example of this, not being able to form until 100,000 years after the big bang.
Perhaps now you have a state where you can have structural formations, composites of atoms interacting together in a new structure - like for example in stars. And in those new states, in turn new forms of structure might emerge, like atoms fusing together to form heavier atoms. And from there perhaps those atoms by their interaction will come together to form spherical structures, and on some of those spherical structures, organising principles there will allow for complex chains of molecules. Which in turn might serve as templates for creating copies of the complex chains. That process might become better at doing so, creating a new means of generating complexity. And so on...
By now the principle should be illustrated, that is to say that if we take the events looking through time instead of back at them we should tend to see the gradual emergence of more complex structures by pure necessity.
I'm not saying this is the way that it happened, or even that it could happen this way. It's a means to think about the problem in a different way. That we look backwards means we aren't seeing the process, instead seeing a whole lot that needed to be the way it is for us to exist. But why shouldn't there be a whole host of things necessary for our existence? We exist, therefore the universe must have the conditions necessary for our existence.
A parallel argument is invoked by those who support biological fine-tuning called Irreducible Complexity. This suffers from the same process, it's looking backwards at what there is instead of considering the process by which to get to it. Can evolutionary theory account for irreducibly complex structures? It can! Any mutation that is advantageous may through later mutation make it necessary. Thus the structure looks like it is evidence against a gradual process, but only because it's looking after the fact instead of considering how the process works.
And I think the same error in thinking in all fine-tuning arguments. It's looking for that which is hard to explain by conventional thought without giving consideration as to what can explain it. By attaching huge improbabilities to that particular structure, it makes it seem like it needs a grand explanation.
One final thought is that perhaps this line of argument falls into irrelevancy if humans aren't treated as a necessity. That it could result in observers doesn't mean that the goal of the universe was to have observers. Likewise that evolution created sapient beings doesn't mean that evolution was made to create sapient beings. That we did evolve and that we do have the capacity to observe the universe says nothing about the laws of nature other than they have to be that way necessarily. It's because we are here to observe that we know that, but they are not that way so that we can be here to observe. Putting us as the focal point generates the improbability because we are very improbable - just like everything else!
1 comment:
That evolution created sapient beings doesn't mean that evolution was made to create sapient beings.
Indeed. Given that all species on the earth are insects (to a first approximation) it would appear that evolution was made to create them. The rest of us (including poor H. sapiens) are but accidents in the glorious realm of our chitinous overlords.
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