Why did it take so long to produce us?

Johninch

Since writing the OP I have realized that I forgot to define intelligence. I wrote. “There have been many long periods of excellent conditions for intelligent life, but all we ever got was a huge amount of unintelligent diversity, until now, after 4 billion years. If brain based intelligence is only a further development of the sense organs, I wonder why it took so long to evolve large sophisticated brains, considering the advantages of intelligence for survival and proliferation.”

Indeed, as you imply, it is not proven that the degree of intelligence now existing on this planet assures survival and proliferation. If our type and degree of intelligence within the context of a few million years is unstable, then from the point of view of an intelligent universe, we are irrelevant.

What we have is a particular (perhaps better phrased “peculiar”) physical development which may well be described as including intelligence from our point of view, but this is egocentric.

The possibility which you suggest “that we are essentially alone in a galaxy teeming with life” does imply the probability of higher intelligences, but the degree of intelligence which should exist elsewhere is difficult to formulate without a definition of intelligence and without knowing the full range on the upside.

Most people assume that we are a long way off the upper limit, which gives rise to the probabilistic assumption that we have a lot of intelligent and super-intelligent co-existents in this galaxy.

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Evo

Don't forget there were a number of extinction events and if it wasn't for the last one, we might not be here. You might say we're an accident.

etudiant

Surely that further strengthens the argument that intelligence is very rare.
Extinction events happened every few hundred million years, so several different life forms got their turn at bat here on earth. Life popped up fast on Earth, intelligent life not so much, even though competition was always driving and presumably favored intelligence.

It may be that there are other forms of intelligence, maybe whales and dolphins just can't be bothered with our kind of thought, but again that makes human style intelligence pretty special. This capability, which took about a third of the age of our universe to develop, might well be entirely unique, as Fermi's pointed comment suggested.

Johninch

So far as I can see, all species are accidents.


Perhaps to answer the question, we should define intelligence. I don’t mean in human terms such as in the debate about IQ, I mean what does intelligence mean in the context of the universe? Competition is an interesting term too.

What we do is to look at earth-bound biology and then go looking for it elsewhere, as if earth-bound biology is the standard for the universe. That could be the explanation of why we don’t find it. If we would rather first define intelligence, we would know what we are looking for and would have a much better handle on the chances of finding the different sorts of intelligence and how to go about finding them.

When I look at the biology of the brain, I get the impression that it is very fortuitous how it works.

So can someone define intelligence for me, without taking homo sapiens type intelligence as the starting point?

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phungus420

We should be using humans as a starting point. An organism could be highly cognizant, able to process huge amounts of information, but it's all irrelevant from a fermi paradox/drake equation perspective if that organism doesn't have the ability to produce communication or transportation technologies that can be carried into interstellar space.

In my opinion it's all about language. Human intelligence is unique not solely due to our cognitive abilities. Human brains are designed to take concepts, encode them as auditory signals, and then process these auditory signals to create unique concepts - that in itself is powerful solely for it's ability to categorize and compartmentalize concepts for further processing. What makes it really special though is that we are compelled to communicate and share these auditory signals in mutually understood structures and syntax (known as language) which allows for further and unique as well as parallel processing by multiple brains. This and our innate use of technology (the species evolved from technologically dependent organisms and has all sorts of hard wired behaviors, such as kinesthetic projection to efficiently utilize technology) is really what makes humans special. It's not all about smarts.