When it comes to evolution, one of the arguments leveled against it is “How can something so complicated as a human being accidentally evolve? It’s like a watch accidentally coming together by shaking the parts around in a box.” The answer is, of course, “Yes, the chances are extremely unlikely - like 1 in a billion - but the thing is, we have had a billion chances, so to speak. That is, evolution has been going on for about 4 billion years now, and that’s a long enough time for something so unlikely to happen at least once.”
Here’s what I’m wondering. Do scientists or mathematicians have a way of actually calculating the odds of human evolution? How “amazing” are we really? Similar statistics have been attempted for life on other planets. We just take the number of stars, number of stars with planets, number of planets with ideal conditions, etc. What would we have to take into consideration for a calculation of the probability of humans evolving on Earth? How accurate could we expect those calculations to be?
It depends on what you mean. Do you mean the species H. sapiens itself, or do you mean the development of any tool-making, social intelligence similar to that of humans?
If you mean humanity precisely, then the chance was very low. However, the same could be said of any other species, the evolution of which was a low-probability event (or rather, series of events) in competition with other, equally low-probability events, one of which had to actually come true. So no matter what happened, some outcome would have occurred whose probability could be estimated as very low.
If you mean the more general concept, there’s a debate on that, but my own opinion is that it’s pretty high. Given life, and enough time, the development of intelligent life is virtually certain.
So, let’s say that humans share 94% homology with our closest living relative.
Let’s say that each species has diverged the same amount from the ancestor. (So the 6% becomes a 3%)
Let’s say the human genome has 3x10^9 base pairs
Let’s say that the mutations were totally and completely random
Let’s say there haven’t been any changes in genome size
Let’s say humans vary from each other by 1% on average (so 3-1=2%)
So, we a 2% difference from our ancestral species, that is 6x10^7 different base-pairs. Since there are 4 base pairs, that would be (6x10^7)^4, so that would be 1.3^31. that ‘^31’ means One-thousand billion billion billion. So, under these assumptions (some of them correct, some of them not-so-much), the chance is 1:1.3^31. But here’s the clincher: it’s that random for every species, humans aren’t special in that regard.
But this is really a statistical artifact, since you are defining a very specific goal, so it isn’t too meaningful.
Edit: Just realized I had a huge brainfart when I did this. It isn’t (6x10^7)^4, but rather 4^(6x10^7), which is a number so impossibly large, I don’t even wanna think about it.
With what western science endorses now, the odds are precisely zero.
Only entropy is explained, not the opposite, which is obviously necessary for the reproduction of any structure.
Entropy progresses only in closed systems. The earth is an open system: it receives a constant influx of solar energy. The solar system is, more or less, a closed system, and entropy does increase in the solar system as a whole, because the increase in entropy within the sun itself far exceeds the decrease in entropy caused by sunlight falling on the earth.
I mean the latter. But guess that makes the question more or less the same as the “intelligent-life-on-other-planets” question. The planet on which an intelligent species evolves being Earth doesn’t really make a difference. Maybe we could answer the evolution question by answering the life-on-other-planets question.
I like the ideas in this thread, but overall I was wondering if there has been a formal analysis done - something involving prefessional statisticians, biologists, etc. coming up with the best estimate they can on the odds of some intelligent life evolving.
No, because, again, the odds are zero, given the theoretica we accept as valid. It’s vital to understand that, even if in a one to ten billion chance a cell might be produced accidentally, there would be one to ten billion squared that chance of that cell reproducing before it fell apart, and so on. The seductive mistake is to think that once structure has by chance been established, it will logically reproduce and increase. But the chances of that are far smaller than the chances of the structure coming together in the first place. If we go by traditional physics, the universe becomes a quadrillion times unlikelier every nanosecond of it’s existence.
Gib,
I think the problem is that what you are asking for is contingent upon waaaay too many variables for anyone to even think about doing it formally (or in a professional capacity) without fearing that they would be laughed out of their University. The only sort of person who would seriously think that they knew enough to calculate the chance is the same sort of person that is in contact with the Mothership.
In order to even begin answering your question, we would have to have a sample set of planets that had life on them and a few of them with sentient life. Then we could at least start taking a stab at it. With what we know now? We've got no idea.
So granted that the chances of intelligent life forming are next to zero, you must believe there is something else going on besides random chances to produce us… or do you think of this as an extreeeemely lucky break?
An alien race designed our biology, first cell. The race came about in another physical context, universe, parallel universe, or maybe they are intelligent standing waves inside stars.
The universe is not 20 billion years old but many times older, enough so that even the slimest lucky break can occur.
God created the universe. Which God ? Allah, Christian, Maya, Vodoo, invent your deity here.
We live in a simulator matrix; We are a brain in a vat; We are in a multiple universe having many laws of physics; we live in a universe THAT DOES NOT HAVE ANY LAWS OF PHYSICS, but just our small corner appears to have some.
Would it matter which one of these were true ? Unless it could bring some kind of new technical capability in our ability to manipulate matter, any of these possibilities are equal. Then if there were any way to find out which one is true, it would probably be too late to do anything about it.
So maybe we are in a computer simulator, but there is a barrier to our ability to find out. We can’t interact or even ever know if it is true. So maybe there is a god and we find out when we die. I mean all the possibilities are abstract, have barriers to our ability to know. If they were aliens, they could come down and state that we are a product of their design. But until that happens, WE CAN NEVER KNOW, AND MOST OF ALL, WE CAN NEVER EVEN BE ABLE TO KNOW.
I would find it hard enough to believe in random chance when I look at my own life even if I was ignorant about the physical impossibility. Yes, I believe there are some fundamental natural laws that haven’t been formulated yet. This is no secret, though. theoretical physics has been in a deadlock for almost a century now.
"Quantum physics in it’s drive to mechanistically dissect matter ever further in order to finally arrive at the ultimate elementary particle has finally reached a point where it is forced to question it’s own paradigm.
Quantum physicists now question the stability of matter itself and seem to arrive at a concept where elementary particles are seen as mere perturbations “on the surface of an endless sea of energy” which some scientists have agreed to call “Zero point energy” or “Torsion Fields†(Kozyrev et al.)"
Although mutation is random, the guiding principle of evolution is “survival of the fittest”, not “survival of the luckiest”. Standard evolutionary theories do not say that a complicated species like us came about by chance; rather, we came about because of the survival value of our traits. Therefore it’s not the case that a species like us evolved to our “unlikely” state solely because of the long time frame available (though it’s an important factor). More than luck and time were involved.
If I put 1 billion numbers into a hat, your odds of blindly picking out a specific number are extremely low. But your odds of pulling out a number are extremely high. That’s the problem with the question- if you stubbornly cling to the notion that evolution has the goal of creating a specific organism, like homo sapiens, the whole idea of it occuring thru “random chance” seems preposterous. But if you accept that there’s nothing inherently special about our species, and explore the notion that we’re an incremental step down a chain of processes that have occured for billions of years, the whole thing starts to snap into focus.
You are all missing the point; natural selection only occurs when there is structural cohesion in the first place. You all take this as a given, since it occurs. But try to explain how it systematically occurs, and you’re stuck.
Chance would have only occasional cohesion immediately disbanded by entropy. Natural selection doesn’t come into the picture until the system is up and running for a long time.
Membrain’s comment has nothing to do with determinism. The point is that probability can only be assigned to future events based on present knowledge. It is absurd to start with present knowledge and try to assess probabilities for the occurrence of various past events. This is simply not how mathematical probability is used, so your original question is unfortunately based on a confusion on the meaning of the word “probability” or “odds”.
To illustrate, let’s say you measured the time when you woke up this morning. And let’s say you measured it incredibly accurately, say with an error margin of a hundred trillionth of a second. You can say to your self in retrospect “wow, imagine that I woke up at precisely this moment, how incredibly low is the probability of this event!” but that is nonsense. If you say “what are the odds that I will wake up at this exact same time TOMORROW morning?”, then you may rightly conclude that the odds are indeed incredibly low.
I could give more refined arguments, but the main points should be clear: you can only assign probabilities to future events. Not to present events, not to past events. And your assessment of a given probability will depend on your knowledge of the present. This is the basic “epistemology” of probability.
This is nonsense. If I tell you I played a dice poker game and threw six full houses in a row, you can calculate the probability of that precisely in the same way as when I asked you to calculate the odds that I would throw six full houses in a row in a game tomorrow.
