There are also a lot of living beings with no nervous system at all, and there's no confusion either about whether they're classed as living beings or not. I d

There are also a lot of living beings with no nervous system at all, and there's no confusion either about whether they're classed as living beings or not. I don't get why nervous systems should be brought into the discussion. Most living beings on Earth do not have any kind of nervous system, and I don't see any obvious reason for why fungi or plant-like life forms could not be as big as galaxies.