This chapter contains spectacular claims for the Greeks.
Unique and important traits of Greek inquiry:
In this chapter, Thornton's claim is basically that western science started with the Greeks, both literally and in the sense that its driving spirit was imparted by the Greeks. He also claims that science and technology are good things all things considered, but that is a separate claim.
At the end of the chapter, as is usual with Thornton, he points out that the topic of his chapter, human rationality, and his thesis (that the Greeks first set humans on a path which gave supreme importance to rational explanation) came in for criticism from the Greeks themselves. In the past few chapters, I have heard from several students that "Thornton just contradicts what he says in the beginning." That is not true, for Thornton is reporting what the Greeks said, and the Greeks said contradictory things. That there were many eminent Greek thinkers who placed their faith in reason is true. It is also true that many Greeks thought that that faith in reason was misplaced or excessive. The positions that the Greeks took are contradictory, but Thornton is not contradictory to report them accurately. In fact, that the Greeks disagreed openly with each other is one of the greatest strengths of Greek culture over "traditional societies" where disagreements, I think, tend to be resolved and forgotten rather than worked on for many generations. The Greek faith in the power of human rationality, through a competitive effort, to explain the world is on display even here where the Greeks disagree about rationality itself and its value.
As is also usual with Thornton, he compares the Greeks to their contemporaries and finds that none of their contemporaries had such a reverence for rationality and an ability to separate rational inquiry from traditional dogma. In particular, Greek thinkers were not confined by religion, for there was no official state religion and no strait jacket of orthodoxy. Nevertheless, occasionally atheism was made a crime in Greece. Socrates, Euripides, and Anaxagoras may all have been accused of atheism. But there were Greek thinkers who altogether denied the supernatural. Most, however, kept some role for the gods, even if they were completely transformed and no longer recognizable as the gods of traditional Greek religion. The contemporaries to which Thornton compares the Greeks have nothing like the separation of science and inquiry from the state and religion which Greeks had. And that separation is not at all confined to Athens, as is the case with some other claims about the Greeks.
A further trait that separates Greeks is that they thought about the nature of what they were doing. They did not just conduct rational inquiry (all cultures do that to some extent), but they also thought about the nature of rational inquiry itself. They invented epistemology and all the "meta" thought that is such a catchword among the mostly nihilistic sceptics of modern "theory."
One aspect of Greek thought that Thornton does not mention but nonetheless well illustrates is that there is a lot of variety to Greek thought. There is no one predominant orthodoxy about any intellectual issue among the Greeks: they are constantly throwing out competing ideas, and the competition is sustained over hundred of years. That spirit of inquiry coupled with a love of competition is a strong legacy which we see present today too. Combined with the scientific method it has created a formidable engine for scientific progress.
A criticism often leveled at the Greeks is that they did not use experiments. By and large that is true, but occasionally they did. They certainly did not have that bedrock of science, the "scientific method" of attempting to falsify hypotheses. But the creation of that method arose from elements that go back to the Greeks and they had other important elements of science.
I want to close this set of brief observations with one of my own: the "Greek legacy" and "western" civilization are Greek and western only by accident. If I took a baby from the deepest darkest most benighted non-western region on our planet, and raised the child and sent it to university, it would have no problem being a "westerner," participating in democracy or engaging in science. And if I took a cave people baby, it would also have no problems being a "westerner." And what is more, most of those who call themselves "westerners" have no plausible family connection to Greece. This whole culture is not specific to Greece in a strong way: anyone can borrow the tradition and make it their own. There is nothing particularly "Greek" about it: just being a Greek does not make you more rational, better at politics, etc. It's a historical accident where you are born: you can mix and match traditions. Multiculturalism often seems to want to take the tack of finding all sorts of ways to denigrate the Greek tradition, Europe and the US, and to say "the Greeks weren't really first and weren't that great," but that is a pissy and horrible way to approach the matter: they should be saying "all those good things that the Greeks did first and that are so strong in the west can be used and adopted by anyone anywhere: they are human cultural heritage items, not Greek. Who cares if the Greeks did them first? They are done and anyone can now use them." The real problem with the west and its Greek heritage is that it gets things done better than others and along with many good things, much of what it wants to do is not admirable. That is a matter of our ethical abilities failing to keep pace with our intellectual and technological progress. The west and the Greeks are not more power-hungry, self-centered, or destruction-bent than other cultures: they are equally power-hungry, self-centered, and destruction-bent, however, and that, combined with their ability to get things done, is the problem. No, I can't measure power-hungriness, self-centeredness, and destruction-bent-ness.