Speakers' corner on the Planet of the Apes.

Ideas about the function of recumbent stone circles have changed over time, from sacrificial altars to celestial observatories. Whilst visiting yet another circle, this afternoon, I suddenly realised that they were probably used as platforms for public speaking back in the mists of time when apes ruled the Earth. Well, it's as good an idea as any other and where's the evidence to disprove it?