This one in particular started out rather poorly, not only not starring John Carter (it'd be a Tarzan book without Tarzan, although not the first time Burroughs has done it thus far), but not even a person related to him or introduced in a previous story. But from there it goes on to what I'm writing about, which is science, religion, and extremism.
Our protagonist who comes to be named Vad Varo arrives on Mars and comes into the care of one Ras Thavas, master of the science of life and physiology. But Ras Thavas practices and studies his science in a very self-serving manner, purely for the intellect and the advancement of his science. Coldly, Ras Thavas says, "Sentiment is indeed a bar to all progress." Truly, in the pursuit of knowledge, he would sacrifice all save himself.
On the other hand, we have the Phundalians who blindly worship Tur, the scripture of the Turgan, and the high priestess Xaxa. From the book:
"He said that the Phundahlians maintained that Tur still created every living thing with his own hands. They denied vigorously that man possessed the power to reproduce his kind and taught their young that all such belief was vile; and always they hid every evidence of natural procreation, insisting to the death that even those things which they witnessed with their own eyes and experienced with their own bodies in the bringing forth of their young never transpired.As you can see, it's quite blunt in its analogy to Christian Fundamentalism. It's probably no coincidence that "Phundalians", phonetically, bears resemblance to "fundamentalism".
Turgan taught them that Barsoom is flat and they shut their minds to every proof to the contrary. They would not leave Phundahl far for fear of failing off the edge of the world; they would not permit the development of aeronautics because should one of their ships circumnavigate Barsoom it would be a wicked sacrilege in the eyes of Tur who made Barsoom flat.
They would not permit the use of telescopes, for Tur taught them that there was no other world than Barsoom and to look at another would be heresy; nor would they permit the teaching in their schools of any history of Barsoom that antedated the creation of Barsoom by Tur, though Barsoom has a well authenticated written history that reaches back more than one hundred thousand years; nor would they permit any geography of Barsoom except that which appears in Turgan, nor any scientific researches along biological lines. Turgan is their only text book--if it is not in Turgan it is a wicked lie.
Much of all this and a great deal more I gathered from one source or another during my brief stay in Phundahl, whose people are, I believe, the least advanced in civilization of any of the red nations upon Barsoom. Giving, as they do, all their best thought to religious matters, they have become ignorant, bigoted and narrow, going as far to one extreme as the Toonolians do to the other."
As the book draws to a close, Ras Thavas is ordered under Vad Varo's suggestion to be restored to his laboratory "Only on condition that he devote his great skill to the amelioration of human suffering". Xaxa is deposed and dead, replaced by one of Vad Varo's friends, and the puppet statue of Tur is operated by Vad Varo's friends as well.
So what is Burroughs saying? Vad Varo and company appear to be people of sound judgement, so leaving the country and followers under their rule doesn't sound like a bad idea. A well-run monarchy is supposedly the best form of government. Clearly he says that science should be conducted with human interests at heart.
On religion, though, he appears to be saying that there is no harm as long as the right persons are in charge. Throughout the series, religion (of course not Christianity directly) is treated largely as superstition and flimflammery; a tool of those in power to keep people in control. It's not just in this book, but "The Chessmen of Mars", and the other books as well, to a lesser degree.