by Dr. Jason Lisle | Jan 9, 2026 | Theology
We have been critiquing Phillip Dennis’s claims that the one-way speed of light must be c in all directions. Einstein claimed that the one-way speed of light was merely a humanly stipulated convention, something that we get to choose in order to define what constitutes simultaneous events that are separated by some distance. Dennis disagrees but has been unable to construct a cogent argument for his claim that doesn’t beg the question. Why does Dennis disagree with Einstein on this issue? I suggested in my previous response to Dennis that it may stem from Dennis’s philosophy of presentism. But what is presentism? Is it a self-consistent, logical philosophy? Is presentism compatible with Scripture?
by Dr. Jason Lisle | Dec 5, 2025 | Uncategorized
In this article, we will examine a particularly embarrassing mistake made by Phillip Dennis in his fallacious attempt to prove the one-way speed of light in all directions must be the same as the round-trip speed. As with all his previous attempts, we will find that Dennis committed the fallacy of begging the question. Namely, he tacitly assumed an equation that arbitrarily presupposes the one-way speed of light at the start. This was the same error made in his previous attempts that I refuted last year (Lisle 2024). What makes his latest mistake particularly embarrassing is that it has already been refuted over 100 years ago (Eddington 1923)! Moreover, it has been refuted multiple times in the last century – including in my book, the Physics of Einstein (Lisle 2018).
by Dr. Jason Lisle | Nov 7, 2025 | Physics, Refuting the Critics
We have been analyzing the claims of Phillip Dennis and his criticism of the ASC model. In particular, Dennis claims to have refuted the conventionality thesis – Einstein’s claim that the one-way speed of light “is in reality neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which I can make of my own freewill in order to arrive at a definition of simultaneity” [emphasis in original] (Einstein 1916). Conversely, Dennis claims that Einstein is wrong and that the one-way speed of light is necessarily the same as the round-trip speed of light: c = 186,282.397 miles per second in vacuum. However, we have already shown that Dennis’s previous attempts to prove this were fallacious because they begged the question. That is, Dennis had used equations that tacitly assume the one-way speed of light. In his latest article, Dennis claims that the one-way speed of light has been empirically measured in two independent experiments. We will examine the first of these here. We will again show that Dennis has once again begged the question. That is, he unwittingly assumed the one-way speed of light is isotropic in his argument.
by Dr. Jason Lisle | Oct 24, 2025 | Apologetics, Physics, Refuting the Critics
In this article, we review – at a layman level – the original argument that Phil Dennis made against ASC and my refutation of his claims. This is important for two reasons. First, Dennis’s first article contained a great deal of mathematics, and this required me to reply in kind. Therefore, my goal here is to explain the disagreement between us without using any equations so that the layman may understand the essence of the dispute.
by Dr. Jason Lisle | Sep 26, 2025 | Astronomy, Physics, Refuting the Critics
This article series will be very important for those interested in the distant starlight issue. Secular astronomers claim that the light from the most distant galaxies has taken billions of years to reach Earth. We can see these galaxies in our most powerful telescopes. Many people conclude from this that the universe must be billions of years old, and therefore that the biblical description of creation is false. But the notion that light takes billions of years to get from distant galaxies to Earth is predicated upon a particular modern convention of how we choose to define the timing of distant events.
