I've read a number of Brian Aldiss' books over the years. While I've never really been taken with any of them, they've left behind a memory of intellectual musing - of a submerged quality of writing that should come out on closer examination. Actually reading the books, unfortunately, doesn't bring it out. To steal inspiration from Aldiss, it's a bit like reading Origin of Species, to find that while convincing and intellectually stimulating in overall concept, the individual passages are extremely dry. Finches of Mars is said to be Aldiss' last SF book, and I'm afraid it submerges his good qualities even further than usual.
The finches of the title refer to Darwin's findings in the Galapagos - finches with widely differing beaks that proved a catalyst for his thinking about natural selection and evolution. The finches in Aldiss' book are the humans of a small Martian colony, who have, in part, consciously evolved beyond religion, at least. That's about as far as the metaphor goes before descending into muddle. The human reaction to a series of still births, a constant topic, is not so much evolution as application of technology.
There's a subsidiary theme about 'an intensity of regret and delight' in considering what is and what could have been and what is missing, especially in the context of failed reproduction and the personal costs to colonists of their travel. While touched on repeatedly, and a frequent topic of character dialogue, Aldiss' message never really goes beyond 'humans feel this'.
Beyond those intellectual elements, the story offers remarkably little of interest. The structure and sequencing are not terribly coherent. The dialogue is wooden and unnatural. The setup and many other aspects are far from credible. Most of the book reads like a (dull) historical study followed by one non-sequitur after another. The ending is jolting. The science is thin, inconsistent, and partly nonsenical, the human motivations even thinner. There are traces of sexism and bigotry. The characters claim that 'important questions engage' them, but thy don't, really. I searched for subtle, clever connections, allusions, allegories. They're just not there, and the whole book is so thickly wrapped in mumbled philosophical fragments that it's difficult to make much of.
In some ways, this book is the antithesis of Andy Weir's The Martian. Where that book was all about optimistic, can-do pragmatism, this one is all about pessimistic despair and ennui. Weir's book observes an individual in a situation that could actually happen. Aldiss describes the entire species through events that never could. Where Weir's book succeeded at simple, matter of fact narrative, this one reaches for intellectual, philosophical complexity and fails. If you're looking for a book about Mars, read The Martian; pass this one up.
I can't recommend this book to anyone but serious Aldiss completionists. His message is good - humanity is screwing up badly. Aside from that, Finches is simply not a good book, and not the memory you want to have of a writer considered one of SFF's masters.