I just finished, and really enjoyed this book. I'm a pretty big reader, but I'm not ashamed to admit that a lot of the time subtleties and even broad themes in fiction kind of go over my head - I'm just along for the ride. With Klara and the Sun, though, I was finding all sorts of ideas and connections popping into my head as I was reading it and I just felt like jotting a few down for the sake of my own memory. Whether this is simply a testament to these themes being particularly interesting to me, or the deft touch of the author, I have no idea.
This is by no means an exhaustive, well-researched essay, I'm sure there are many other characters and themes which could be delved into much more deeply. Just a handful of points which sprung to mind when I started thinking about writing this down.
One of my favourite takeaways from the book, although this is by no means a point which is laboured or made explicitly, is the idea that no matter how well we think we have developed/trained an AI, we can never really know its "thoughts" or how it will view the world. I think it's safe to assume that whoever created Klara did not intend for her to worship the sun as a god-like figure, although it is possible that seeking out the sun was programmed into her as a goal since this is how AFs gain energy, which has had this unintentional side effect.
This god-like worship of the sun led to a range of risky behaviours, such as her treks out to McBain's barn, and her personal sacrifice to destroy the Cootings Machine. Both fairly low stakes in the grand scheme of things, but it makes the point nevertheless that the development of AI can have wildly unintended consequences which are inscrutible to the developers of said AI. This made me think of the thought experiment of an AI Stamp Collecting Robot which ends up destroying the world, excellently described in this Computerphile video.
A slightly more explicit theme on the topic of AI is the question of sentience - what is or is not sentient and what implications does sentience have. We obviously empathise with Klara and so it feels unfair to the reader when Helen compares her to a vacuum cleaner. This is developed in a further interesting way right at the end of the book when we discover Klara has been dropped off at a scrapyard once she has outlived her usefulness. This makes the reader think not only about the disposable nature of objects in our society in general, but especially how this brushes up against objects which are sentient. There are clear allusions here even to how we treat our elderly in our own society, left alone in a care home with nothing but their own memories.
Klara and the Sun is clearly set in a somewhat dystopian society, however world-building is very much not of foremost importance to the author here. We just get glimpses of certain areas of society through the conversations of characters, such as:
The loneliness which is clearly prevalent throughout society. Most of the characters have extremely small friend groups and strained relationships. Artifical Friends are commonplace for young and teenage children to keep them company, and children are coerced (in Josie's case, against her will) into socialising with other humans in quite stilted and standardised ways.
The rich/poor or educated/uneducated gap is extreme in this society. We find out that Josie's dad, and many other high-flyers of traditional industry, have been replaced by machines, returning them to an impoverished, clan-based civilisation exhibiting large amounts of very surface-level prejudice. Exagerrating this is the concept of "lifting", a gene altering process which children can undergo to make them more intelligent from a young age. This not only creates a class division in the sense that presumably only the wealthy can afford to go through with the lifting process, but also creates a prejudice with the lifted arbitrarily looking down on non-lifted, as we see with Rick, despite the fact he appears to be extremely intelligent without having been lifted.
Dystopian societies in fiction are often used to hold a mirror up to our own culture and civilisation, to make us think about how things are and the way things are going. I believe this is very apparent in Klara and the Sun.
Religion and worship
While religion isn't a major theme in the novel, it's clearly touched upon in one key area - Klara's relationship with the sun.
I found the two scenes of her "praying" (for want of a better term) in McBain's barn to be particularly clear cut examples of this. Here we see Klara internally pleading with the sun to carry out a benevolent act for her. Not only that, but Klara constantly interprets and extrapolates from the sun's actions, inferring responses which we as the reader know are just the normal actions of the sun setting.
It's clear to see that this could easily be transferred to the act of a human praying to god, and taking things which do or do not then happen as "signs" from god. I haven't looked it up, but I would imagine that Kazuo Ishiguro is not religious here based on what I read as a fairly cold depiction of the futility of prayer, but perhaps he's just self-aware.