Tam Hunt, UC Santa Barbara, tam.hunt@psych.ucsb.eduThe Lorentz transformations form the mathematical core of the 1905 theory of Special Relativity as well as the earlier version of relativity created by Lorentz himself, originally in 1895 but developed further in the ensuing years. These two theories interpret the physical significance of the transformations quite differently, but in ways that are generally not considered to be empirically distinguishable. It is widely believed today that Einstein’s Special Relativity presents the superior interpretation. A number of lines of evidence, however, from cosmology, quantum theory and nuclear physics present substantial evidence against the Special Relativity interpretation of the Lorentz transformations, challenging this traditional view. I review this evidence and suggest that we are now at a point where the sum of the evidence weighs against the Special Relativity interpretation of the transformations and in favor of a Lorentzian or neo-Lorentzian approach instead.1. IntroductionI’m sitting in a public square in Athens, Greece, biding my time as I write these words. The battery on my phone ran out as I was trying to navigate to my lodgings on my first night in this historic city, forcing me to stop and charge my phone for a little while. I’m waiting for the passage of time.The nature of time has been debated vigorously since at least the age of Heraclitus and Parmenides in ancient Greece. “All things flow,” said Heraclitus. “Nothing flows,” said Parmenides as a counter-intuitive rejoinder, suggesting that all appearances of change are an illusion. How could Parmenides make the case that nothing flows, nothing changes? It would seem, from easy inspection of the world around us that indeed all things do flow, all things are always changing. So what was Parmenides talking about?Parmenides’ arguments illustrate well the rationalist approach that Plato was later to more famously advocate, against the empiricist or “sensationist” approach that Heraclitus and Aristotle too would champion as a contrary approach. Parmenides and Plato saw reason as the path toward truth and they were not afraid to allow reason to contradict what seemed to be obvious sensory-based features of the world. Apparent empirical/sensory facts can deceive and, for these men, Parmenides, Plato and their followers, reason alone was the arbiter of truth. Wisdom entailed using reason to see through the world’s illusions to the deeper reality.Heraclitus and Aristotle, to the contrary, stressed the need to be empirical in our science and philosophy (science and philosophy were the same endeavor in the era of classical Greece). Reason was of course a major tool in the philosopher’s toolbox for these men too, but it seems that reason unmoored from evidence should not be used to trump the obvious facts of the world. The Aristotelian approach is to find a pragmatic balance between empirical facts and reason in attempting to discern the true contours of reality.Einstein was firmly in the camp of Parmenides and Plato (Popper, et al. 1998). He famously considered the passage of time, the distinction between past, present and future, to be a “stubbornly persistent illusion.” This view of time, as an illusory construct hiding a deeper timeless world, was based on his theories of relativity. Einstein and his co-thinkers held this view, of time as illusory, despite the obvious passage of time in the world around us, no matter where we look. The widely-held view today is that Einstein finally won the long war, decisively, between Heraclitus and Parmenides. Despite appearances, nothing flows and the passage of time is just that: only appearance.I suggest in this paper, however, that this conclusion is premature. Einstein’s thinking is indeed an example of rationalism trumping empiricism and it is time for us to take a more empirical approach to these foundational questions of physics and philosophy. Today’s physics lauds empiricism rhetorically, but in practice a rationalist approach often holds sway, particularly with respect to the nature of time.2. An overview of Special Relativity and Lorentzian RelativityIn discussing the nature of time with respect to modern physics, I will focus on the Special Theory of Relativity (SR) and avoid discussion of the general theory. Einstein’s 1905 theory of relativity adopted the Lorentz transformations directly, unchanged from Lorentz’s own version of these equations (Einstein 1905, Lorentz 1895 and 1904, in Lorentz 1937). Einstein’s key difference from Lorentz’s version of relativity (first put forth in 1895, but developed further in later work) was to reinterpret Lorentz’s equations, based on a radically different assumption about the nature of physical reality. Lorentz interpreted the relativistic effects of length contraction and time dilation—which follow straightforwardly from the Lorentz transformations—as resulting from interaction with an ether that constituted simply the properties of space (Lorentz’s ether was not some additional substance that pervades space, as was the case in some earlier ideas of the ether). Einstein, to the contrary, interpreted these effects as resulting from the dynamics of spacetime, a union of space and time into a single notion, and dismissed the ether as “superfluous.”Because Lorentz’s and Einstein’s versions of relativity both use the Lorentz transformations, they will yield in many cases the same empirical predictions. The prevailing view today, then, is that while these two theories are empirically indistinguishable there are other considerations, relating to parsimony primarily, that render special relativity the preferred approach. I discuss below, however, why we now have good empirical reasons to distinguish between these two interpretations—in favor of the Lorentzian approach.Length contraction and time dilation occur as a result of the assumed absolute speed of light because either space or time, or both, must distort if we consider the speed of light to be invariant. This is because speed is measured simply by dividing distance traveled by the time elapsed; and if the speed of light remains the same in all circumstances then space and/or time must distort in order to maintain this invariance. As an object travels closer and closer to the speed of light, its length must decrease (length contraction) and/or the time elapsed must increase (time dilation) – but only from the perspective of an observer in a different inertial frame. In the original inertial frame there is no length contraction or time dilation.“Moving clocks run slow” is a good shorthand for relativistic time dilation, but again only from the perspective of a different inertial frame. Time moves at the same rate for an observer in the moving frame of reference, no matter what one’s speed in relation to other frames. Relativistic effects only occur when considering the relationship between two different frames of reference, not in the same frame.