In this article, I will demonstrate that the philosophy of presentism as espoused by Phillip Dennis is not compatible with the physics of Einstein.  Recall that presentism is the claim that “only present things exist.”  In its strong form, it denies the existence of past things and future things.  I have already shown in the last three articles that presentism is unbiblical and illogical, and that arguments against eternalism are fallacious.  Indeed, the Bible affirms eternalism – that the past, present, and future are equally real.  In fact, all events that have ever happened or ever will happen are already fully known to God (e.g., Isaiah 46:9-10).  In this article we will show that the physics of Einstein requires the reality of past and future events and therefore is incompatible with presentism.  Indeed, the physics of Einstein has rightly been seen as a vindication of the biblical view of time.

We have been examining the philosophy of presentism – the claim that “only present things exist.”  In its strong form, presentism would insist that “only present things exist, have existed, or will exist.”  Of course, biblically, presentism is false because past things and future things are real according to Scripture (and are known by God).  Thus, the Bible endorses eternalism – the claim that past, present, and future are equally real.  But Phil Dennis has criticized eternalism and insists that presentism is true.  Yet nearly all of his arguments are strawman fallacies – criticizing a misrepresentation of eternalism as if it claims that past, present, and future all exist now – in the present.  Sometimes a presentist will retreat to a trivial claim that “only present things exist now – in the present.”  But no one would disagree with this.  Eternalists accept that only present things exist in the present.  But we maintain that the past and future are just as real (true to the mind of God) as the present.  Let’s continue to analyze Dennis’s claims.

In the previous article, we examined the concept of presentism – the belief that “only present things exist.”  We found that there are two versions of presentism, two ways of interpreting the claim: a trivial version and a strong version.  The trivial interpretation merely insists that only present things exist in the present.  No one would disagree with that.  The strong version claims that only present things exist at all – in other words, “only present things exist, have existed, or will exist.”  The strong version is clearly false and antibiblical.  There are past things that have existed that no longer exist, such as the Tabernacle.  And there are future things that will exist but do not exist in the present, such as tomorrow’s sunrise. 

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?

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). 

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.