Why is SETI unsuccessful?

[stevebowers]

AFAIK nobody has worked out the reason for the existence of spiral arms in many galaxies. Maybe they are a common type of engineering project?

That question was the heart of Greg Matloff's recent article at Centauri Dreams. He reckons it is possible that stars themselves are conscious, and move themselves by volition around the galaxy to produce the various location anomalies. This seems to be directly inspired by Olaf Stapledon's Star Maker.

Sentient structures might be too massive to recognise as such, or they might be too small (entire civilisations in a warp bubble) or they might be simply too weird.