Objective reality is what exists independently from Man's consciousness. Stalin and other tyrants also thought that it's a slippery customer and they can create any reality they wish. In fact they only created piles of corpses. I reiterate the principle of primacy of existence. It doesn't depend on what one thinks. But man has volition. He can act rationally, that is -in accordance with reality of nature and man or may ignore it. In the latest case the result is always destruction and death. In order to know what is man should use his senses and mind in to create non-contradictory concepts and non-arbitrary premises. That exactly what sundry mystics of mind and muscle failed to do.