Category Archives: Philosophy

Still Not Living in a Computer Simulation

A couple of commentators on a previous post pointed me to an Arc Digital article by Thomas Metcalf which contends that the Simulation Argument (SA) ought to be taken more seriously. (Metcalf’s article wasn’t written in response to mine, although it appeared a week or so afterward: post hoc sed non propter hoc.)

I don’t think there’s anything in the article that poses any problems for the arguments I gave in my post. Rather than respond to every point, I’ll just quote a few sections and make some comments.

Brain in a Vat

Metcalf observes that the SA has two key premises:

The Empirical Premise: Most of the “people” who think they’re real, flesh-and-blood humans are actually conscious computer programs.

The Indifference Premise: If most people are simulated, then you are probably simulated.

As I explained in my earlier post, I think the first premise is false, and necessarily so. It’s not metaphysically possible for a computer program to be conscious, assuming that the computer in question is a purely physical mechanism. (I think Metcalf actually commits a category error in his statement of the Empirical Premise. A computer program is abstract in nature; it’s a set of instructions that can be run by one or more physical computers. So a computer program wouldn’t be conscious; it would be the computer running the program, if it were possible for a computer to be conscious.)

The second premise looks problematic too. Metcalf elaborates:

The idea behind the Indifference Premise is simple: If most people have some feature, then absent other evidence, you should guess that you probably have that feature.

Most people have the following feature: not being me. Should I therefore guess that I’m probably not me too? Perhaps the “absent other evidence” clause is supposed to foreclose such trivial counterexamples. But what kind of evidence is in view here? Observational evidence? Surely that’s not the kind of evidence that would confirm my self-identity. Self-identity is known a priori. Couldn’t I also know a priori that I’m not a computer simulation? Well, if I can know a priori that no purely material object can be conscious, then I can know a priori that I’m not a computer simulation. All this to say, both premises of Metcalf’s SA seem to hang on the controversial notion that a computer can be conscious.

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The Laws of Nature and of Nature’s God

For those interested, the lecture I gave last October on the theological foundations of modern science has been published in the May 2019 issue of Reformed Faith & Practice. Go here to read it.

Are We Living in a Computer Simulation?

(Spoiler: Betteridge’s law applies.)

I’ve been asked several times recently how I would respond to the claim that we are (or might well be) living inside a computer simulation. I don’t think the folk who pose the question to me are themselves worried the claim might be true; rather, they recognize it as a new kind of skeptical challenge and they’re curious to know how Christians might respond to it. Also, I suspect they’ve encountered some unbelievers who use the simulation hypothesis as a kind of nuclear option to derail serious discussions about the evidence for Christian claims. (“How do you know you haven’t been brainwashed into believing Christianity? How do you know you’re not being deceived by a malevolent demon? How do you know you’re not in a dream right now? How do you know the entire universe isn’t just an elaborate computer simulation? Huh? Huh?”)

As it happens, there are some smart people who take the simulation hypothesis seriously: Nick Bostrom, Elon Musk, Neil deGrasse Tyson, and Scott Adams, among others. They don’t necessarily believe it, but they don’t think it’s implausible. So what can be said in response? Can the hypothesis be refuted?

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Grudem’s Christian Ethics and Other Themeliana

My review of Wayne Grudem’s Christian Ethics appears in the latest issue of Themelios. (In case you’re left wondering: yes, I actually used a set of scales.)

The April 2019 issue is quite a treat. Some highlights:

Something for everyone!

Iron-Man Dualism

One common argument against substance (mind-body) dualism runs as follows. We know that consciousness is dependent on the brain, because when the brain is damaged it adversely affects consciousness and mental function. (You can prove this point to yourself experimentally by hitting yourself hard on the head with a brick.) Furthermore, it is argued, when brain function ceases altogether, consciousness disappears. (Don’t try to prove this latter point to yourself experimentally; just take it on trust.) Therefore, contra substance dualism, the mind — if it’s a real entity at all — must be ontologically dependent on the physical structures of the brain. We should be physicalists of some kind.

I come across this argument all the time in the writings of naturalists, but it strikes me as a blatant non sequitur. At most it shows that there’s a causal relationship between the mind and the body, which substance dualists insist upon anyway. (The so-called “interaction problem,” which is concerned with how there can be causation between physical and non-physical substances, is a different challenge to dualism, one I don’t propose to address here.) The fact that increasing damage to the brain leads to increasing mental impairment doesn’t at all imply that the mind cannot exist apart from the brain.

Here’s an analogy to elucidate why that’s so. Imagine a spaceship of the kind familiar from sci-fi movies. In this spaceship, the cockpit doubles up as an escape pod. In normal operation, the cockpit is attached to the main ship; whenever the ship moves, the cockpit moves with it, just as it should. If the ship is attacked with (say) photon torpedoes, the cockpit is buffeted about along with the rest of the spacecraft. When the ship is damaged, all of its systems can be affected; thus the operation of the cockpit can be impaired by damage to the ship in which it is housed.

If the ship becomes so badly damaged that it can’t move at all, the cockpit is stuck along with it, since it’s fixed to the ship. But if the spaceship is completely blown apart, the cockpit functions as an escape pod: it can detach from the doomed ship, and once detached, it can move freely again. (In line with a Christian eschatology, we could even extend the analogy such that if the parts of the ship are recovered and reassembled, the cockpit can be reattached — but that’s not necessary for the point I’m making here.)

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Blaming Sinners and Exculpating God

Some time ago I plugged Guillaume Bignon’s Excusing Sinners and Blaming God. Kevin Timpe wrote a critical review of the book in the journal Faith and Philosophy, and Bignon has now posted a response to the review on his website. His response is useful because it not only rebuts Timpe’s criticisms, but also takes the discussion further in some respects. Check it out.

Faith and Philosophy Journal Now Open-Access

Splendid news: Faith and Philosophy, the journal of the Society of Christian Philosophers, is now open-access. Kudos to the SCP Executive Committee for that decision and its execution. All articles and book reviews from all past issues (dating back to 1984) are freely available for PDF download.

Faith and Philosophy

The journal archive includes many classic articles by luminaries such as William Alston, Robert Adams, Marilyn McCord Adams, Alvin Plantinga, George Mavrodes, Eleanore Stump, Richard Swinburne, Nicholas Wolterstorff, Peter van Inwagen, and William Wainwright, to name but a handful. Happy reading!

Determined to Believe?

Determined to Believe?John Lennox is Emeritus Professor of Mathematics at the University of Oxford and an evangelical Christian with a longstanding concern to defend the Christian faith in the public sphere. In recent years he has risen to prominence as an articulate, well-informed, and winsome apologist, writing books on the relationship between Christianity and science, and engaging in public debates with prominent skeptics such as Richard Dawkins, Christopher Hitchens, and Michael Ruse. His 2007 book God’s Undertaker, which I have often recommended to my students, deftly debunks the myth of conflict between religion and science. I wish I could be so enthusiastic about his recent foray into systematic and philosophical theology, which might well have been titled Calvinism’s Undertaker.

As Lennox explains, his latest book “is written mainly for Christians who are interested in or even troubled by questions about God’s sovereignty and human freedom and responsibility” (15). Having been asked on many occasions to share his views on this thorny issue, Lennox decided to embark upon a book-length treatment of the topic. The primary target of his book is theistic determinism, which Lennox nowhere explicitly defines but apparently takes to be the view that God determines—more specifically, causally determines—every event in the creation, including the decisions and actions of his creatures. The book consists of 20 chapters and is divided into five parts. In this review I will summarize the content of each part, offering some critical comments along the way, before concluding with some concerns prompted by the book’s title.

Read the rest of the review here.

Is Calvinism Unliveable?

It’s sometimes claimed that determinism is irrational because (so the argument goes) one can’t consistently believe that one’s beliefs are determined. Occasionally this is transposed into an objection to Calvinism, since Calvinism is arguably committed to theistic determinism.

Let’s take a look at a recent example from William Lane Craig’s weekly Q&A blog and consider whether the objection has any substance. (Craig’s article was reproduced on Biola University’s blog several months later, so it has had some exposure.)

A correspondent writes to Dr. Craig:

As a former agnostic, one of the most powerful apologetic arguments against naturalism, atheism (and so on) is the idea that nobody strives to be a *consistent* naturalist/atheist/etc. In other words, they fail to act in accordance with the nihilism to which many of these ideas logically lead. Being more than a little curious, I stumbled into the free will position within Calvinism. Doesn’t this lead to a similar problem? In other words, what exactly does a consistent Calvinist even look like?

What does a consistent Calvinist look like? Well, if you’re really curious, you can find out here. But moving on to Craig’s response:

I think that you’ve successfully identified a problem with determinism in general, Leif, of which Calvinism is but a specific instance, given the Calvinist’s view that God determines everything that happens.

Note first that Craig treats Calvinism as merely one species of the genus determinism, taking it that any problem with determinism in general must afflict Calvinism’s theistic determinism. I doubt things are that simple. It’s pretty difficult to generate an argument against determinism as such, which is why most anti-determinist arguments target particular types of determinism (e.g., physical determinism or nomological determinism).

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Snowman Identity Over Time

An exchange with my five-year-old son:

“I just watched the Snowman movie. It’s kinda sad at the end.”

The Snowman“Why’s that?”

“Because the snowman melts. I hope the boy can build him up if it snows again.”

“But what if all the snow completely melts and there’s nothing left of him? If the boy builds up the snowman with new snow, would it be the same snowman or a different one?”

“I think it would be the same one.”

“Why do you think that?”

“Because the boy would use the same stuff to make him.”

“You mean the same hat, scarf, lumps of coal, and all that?”


“I think you could be right. Let’s hope it snows again.”