Does it feel any different to be reverse-chiral life?
I will examine the concept of chirality (the difference between a right hand and a left hand, generalized) and its relevance to philosophy of mind. Philosophy of mind often deals with colors: colors of worldly objects and of mental representations of them. Chirality, like color, can be experienced: it feels different to look at a left hand compared with looking at a right hand. Physics treats chirality more directly than it treats color. Parity symmetry is a feature of some physical universes, but not our own. A parity symmetric universe (assuming it is, like ours, 3D in spatial coordinates) has the property that a universal parity inversion (which negates x, y, z coordinates of everything) makes no physically detectable difference. Parity symmetry is broken in our universe; this was shown in 1957. As a science fiction exercise, I imagine a universe much like ours, but with parity symmetry. In another universe... In this parity-symmetric universe, physicists fail to detect any parity violation, concluding that parity symmetry really does hold. They conclude that a possible cosmic state of affairs, and its parity inversion, are physically equal. There is no physical difference between them, only a change in coordinates. The universe needs no absolute chirality, any more than it needs absolute spatial coordinates: chirality is not an intrinsic physical feature of objects. Philosophical attitudes differ. Physicalists believe the physicists' parity-invariant ontology is correct: absolute chirality exists neither in objects, nor in mental perceptions. This ontology is counter-intuitive, because the experience of looking at a normal clock seems different from the experience of looking at a backwards clock. Chiral materialists believe that physicists have left something out of their description of the universe. They believe that objects really do have absolute chiral properties: a forwards clock is intrinsically different from a backwards clock. Chiral materialists hold th