When I read this in HHTTG I thought Douglas Adams had gone too far. There can be no such thing as a super-intelligent shade of the colour blue. But I’ve had a rethink over the past few days, caused by reading about what plants think and uncovering an alien race in a Stephen Baxter book characterised by being a shade of blue. Consider.
Many strong-colour dyes are known as aniline dyes. These dyes are organic molecules, not too different to the organic molecules found in all living things on Earth. They contain aromatic rings, like purines and pyrimidines in RNA and DNA, and also contain nitrogen like purines and pyrimidines. Aniline dyes also contain sulphur, like proteins. They contain no atoms other than those commonly present in living things on Earth.
Let’s be more specific and consider Aniline Blue . This is a mixture of two distinct different chemicals known as “water blue” and “methyl blue”. Now let’s suppose that these are strung together, perhaps in a similar way to the way that purines and pyrimidines are strung together in RNA. The string of Aniline Blue would represent a binary code depending on the sequence of the two components in turn. It’s not too much of a stretch to consider this as an RNA-like inheritable template for constructing organisms based on this binary code. This would be a carbon-based lifeform, and therefore more likely than any non-carbon-based (eg. silicon-based) lifeform.
The ratio of the two distinct components of Aniline Blue in the genetic material would give it a very specific shade of blue, and being alive it could develop intelligence.