Apologies (for any who noticed) for the recent hiatus, but thanks to both Michele and Ironspider for their recent comments.
It might seem odd to talk about 'Novel of ideas' in SFF as a great deal of SFF is based very clearly on a hypothetical or an idea from science and/or philosophy. Obviously, some are just flights of pure fantasy or space opera, but many aren't.
But just the other day I finished reading Jo Walton's "The Just City" which is a remarkable book - basically, the Greek God Apollo is confused by something that has happened and is trying to understand the reasons why. To help him in this, Athena and he agree to create a City State on a remote island populated by real figures from history such as Plotinus, Cicero, and Marsilio Ficino in order to see whether or not Plato's 'Just City' is possible. It's a great read if you haven't come across it before.
So my question is - what other books or stories in the SFF tradition have really tried to explore a complex scientific and/or philosophical ideas? And which have been your favourites and why? There are many to choose from of course - H.G. Wells is a good example, for instance. So let us know below.