What is Objectivity?
The December 5, 2011, issue of Scientific American ran an article titled "New Theory Explains How Objective Reality Emerges from the Strange Underlying Quantum World". In it the author describes how the classical world arises from the quantum world, how he and his research colleagues at the Centre for Quantum Technologies at the National University of Singapore conducted experiments to measure the fabric of reality by applying quantum correlations and found that "Whatever quantumness is present can never be strong enough to contradict local realism [objective, mind-independent reality in the macroscopic world]. It is, after all, reassuring to know that the moon is there when you don’t look at it." [Berkeley notwithstanding]
Physics is not philosophy, to be sure; although physics offers philosophers a window into the mysteries of the universe. But how are we to interpret the empirical data of science? How do we know what we know? Indeed, what is knowledge? And can we know anything at all about the real world in which we live? These are the central questions of epistemology.
Is there an objective reality behind what we see and experience? Was Einstein right when he wrote in a letter to Langevin on December 16, 1924, that Louie de Broglie had "lifted a corner of the great veil" in his PhD thesis on the discovery of matter waves? Or when he said during an intellectually riveting discussion he had with the Indian philosopher Rabindranath Tagore in July 1930, in his home on the outskirts of Berlin: "I cannot prove scientifically that Truth must be conceived as a Truth that is valid independent of humanity; but I believe it firmly. I believe, for instance, that the Pythagorean theorem in geometry states something that is approximately true, independent of the existence of man"?
Is there such a thing as "objective truth", i.e. the belief that truth is objective, independent of us, of our beliefs, and of the operations of our minds? The notion that regardless of what we believe, some things will always be true and others will always be false? If not, then Nietzsche must have been right when he said there are no facts, only interpretations.
But if there is, can the human mind ever grasp it? Or is there an impenetrable Kantian barrier between what reason can comprehend in the phenomenal world of appearances and the world in itself, the world of objective reality not immediately accessible to our senses?
In practical terms, is there an objective reality behind our interpretations of experience? Do we experience the objective world in which we live? When we claim to be "objective", what exactly do we mean?
In short, what is objectivity?