Things that can be tested, measured, calculated, repeated and predicted form our reality. Reality is also defined in terms of existence and substance, as opposed to things that are abstract, imaginary or fictional. Yet another definition of reality is things that can be known factually, as opposed to mere conjecture and speculation.
The body and brain are physical objects that exist in time and space. They are real until they die and disintegrate, then they are reduced to atoms and molecules. Memories of the dead continue to live on in the minds of the living, until they too die and disintegrate. All real things–every animal, tree, mountain, river, continent, planet, star and galaxy–will eventually be destroyed and reduced to atoms and molecules. This is the realm of classical physics.
Metaphysics differs from natural science in that its scope extends beyond the visible and the natural to encompass the invisible and the supernatural. The term metaphysics is derived from the Greek Ta Meta ta Physkia, which means “the books after the books on nature.” When a librarian was cataloging Aristotle’s works, he did not have a title for the material he wanted to shelve after the material called “nature” (Physkia) — so he called it “after nature.” In contemporary culture, metaphysics has come to mean everything that exists outside the realm of science. For many scientists, metaphysics means non-science and is a close cousin to non-sense. For many atheists, metaphysics is synonymous with all irrational beliefs from leprechauns and goblins to ghosts, souls and gods.
The materialist philosophy of modern science is built upon the foundations of philosopher David Hume (1711-1776) and physicist Ernst Mach (1838-1916). Hume denied the existence of a supernatural realm, therefore any appearance of supernatural or miraculous activity must necessarily have a natural explanation, even if that explanation was inaccessible to current scientific knowledge. Mach limited the realm of true science to statements about the world that can be verified by experiment or observation. Therefore, speculations that are intrinsically not verifiable are not scientific. Mach’s definition would exclude quantum physics, multiverses, black holes and dark energy from the realm of science.
Decades later, evolutionary biologist Steven Jay Gould (1941-2002) described science and religion as non-overlapping magisterial (NOMA). The scientific magisterium covers “the empirical realm: what the universe is made of (fact) and why does it work in this way (theory). The magisterium of religion extends over questions of ultimate meaning and moral value.” Gould was criticized by fellow scientists for being overly generous to religion by removing meaning and moral value from the ‘real’ world of natural science. Gould was following the logic of Mach and other positivists whose determination to reduce the influence of religion on science created a polarized, dysfunctional model of reality.