A few more thoughts inspired by Tim Maudlin's remarks in an interview with the Atlantic magazine. I'll quote Tim again first:

The question remains as to how often, after life evolves, you'll have intelligent life capable of making technology. What people haven't seemed to notice is that on earth, of all the billions of species that have evolved, only one has developed intelligence to the level of producing technology. Which means that kind of intelligence is really not very useful. It's not actually, in the general case, of much evolutionary value. We tend to think, because we love to think of ourselves, human beings, as the top of the evolutionary ladder, that the intelligence we have, that makes us human beings, is the thing that all of evolution is striving toward. But what we know is that that's not true. Obviously it doesn't matter that much if you're a beetle, that you be really smart. If it were, evolution would have produced much more intelligent beetles. We have no empirical data to suggest that there's a high probability that evolution on another planet would lead to technological intelligence. There is just too much we don't know.

Certainly it is remarkable that only one technology-using (if you discount a few cases of the most rudimentary use of natural objects, and perhaps a few cases of very rudimentarily modified objects, as tools by other animals) species has evolved on Earth. An interesting question is whether most planets that do evolve life eventually evolve species that produce and use complex technology, and how many such species. My guess, certainly not supported by long consideration, but by a modest amount of offhand thought, is that given enough time, they do. My guess is also that it takes a fair amount of time for evolution to produce such a species, and that this is part of an overall evolution towards increasing complexity, in some sense I'll here leave ill-defined, of the overall web of life on the planet, and in particular, of the most complex species on the planet. (Perhaps the notions of complexity explored by Charles Bennett, Murray Gell-Mann, and Seth Lloyd may be relevant.) Since the environment in which organisms must survive and propagate evolution consists in significant measure of other organisms, evolution itself creates new niches in this environment for organisms to evolve toward filling. As Robinson Jeffers wrote:

What but the wolf’s tooth whittled so fine
The fleet limbs of the antelope?
What but fear winged the birds, and hunger
Jewelled with such eyes the great goshawk’s head?

While I don't see a clear and obvious argument for it offhand, it is plausible to me that this process tends over time to create more and more complexity. In this sense, I suspect there is "progress" in evolution, despite a fair amount of scoffing in some quarters at the notion of evolutionary progress. This looks like a fruitful area for research. It's also plausible that this sort of evolutionary progress may eventually create both a niche for, and an accessible evolutionary path towards, a technology-using intelligent species. Whether the fact that we have only a single such species on this planet is due primarily to their being essentially only one niche for such a species, to the fact that it takes a long time for such a species to evolve due to the many precursor steps necessary (this would need to be a rather tricky anthropic argument, I suspect), or just happenstance, seems even more speculative, but very interesting.

So it seems to me I find myself supporting, at least speculatively, what may seem the naive, knee-jerk view "that the intelligence we have, that makes us human beings, is the thing that all of evolution is striving toward". With allowance for a metaphorical use of "striving", and modification of the definite article ("the thing"), I'm not too unhappy with that characterization. How far things go beyond "the intelligence we have", though, I'm not prepared to say. And it may be that there are very different paths for a planetary ecosystem to take, other than the production of one (or a few?) technology-using species. As Tim says, in the end we really don't know. But I do think there is interesting knowledge to be sought here.