Can You Prove a Miracle?

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I’m currently taking a week off work, having submitted a draft of my book manuscript (‘The Purpose of Existence: Between God and Atheism’). Sometimes when I take time off, I get lost in a rabbit hole or two. On Easter Sunday, I listened to a debate on my favourite Christian vs. Atheist debate podcast on whether you could demonstrate historically that Jesus rose from the dead. I Tweeted brief thoughts about this, and someone tweeted back at me about a recent six-hour debate on this topic by atheist New Testament scholar Bart Ehrman and Christian New Testament scholar Mike Lacona. I ended up paying $50 to watch all six hours of it, and would like to share some thoughts about it.

I found the debate incredibly frustrating. There was very little disagreement on the historical facts, apart from whether a miracle occurred. Both accepted that after Jesus died several of his followers had experiences which persuaded them that Jesus had physically risen from the dead (Ehrman thinks there’s good evidence that at least Peter, Paul and Mary Magdalen had such experiences). Rather than disputing the history, a lot of time was taken up arguing about whether it is possible for a historian, as a ‘historian’, to argue for a miracle. This seems to me a very silly thing to argue about. We could define the word ‘historian’ however we wish. Surely the interesting question is what we have reason to believe.

Moreover, there was also no mention of our mathematically precise was of understanding how evidential support works, namely Bayes theorem. According to Bayes theorem, the probability of a hypothesis is determined by two things: evidence and prior probability. The ‘prior probability’ is simply how likely the hypothesis is before we take the evidence into account. It seems clear that whether a case can be made for the resurrection is going to hang on the prior probability of the resurrection. Suppose you’re an atheist who thinks the odds of God existing are one in a billion. You’re obviously going to attach an even lower probability than that to God having raised Jesus from the dead. From that starting point, you’re going to need quite extraordinary evidence to get the probability of the resurrection up anywhere reasonable. And even if there is evidence for the resurrection that is fairly strong by the standards of ancient history, it’s clearly not that impressive. For this reason, I don’t think atheists should be worried about conceding to Christian apologists that there is non-negligible evidence for the resurrection. There is strong evidence for all kinds of things that we nonetheless have absolutely no reason to believe, precisely because the prior probability is so low.

Bayes theorem tells us that if a hypothesis renders the evidence less improbable than it would otherwise be, then the evidence supports that hypothesis. Suppose, for example, that Joan’s DNA was found on the body, and that that’s really unlikely unless Joan is the murderer. It follows that we have evidence that Joan is the murderer, as that hypothesis renders the DNA evidence less improbable than it would otherwise be. On the face of it, it is fairly improbable that several people would hallucinate Jesus being back from the dead, especially when one of them (Paul) was a zealous and violent opponent of the Christian movement. Whereas if Jesus really did rise from the dead and appear to people, then it’s not so surprising that those people would have experiences that persuaded them that he was risen from the dead. It’s pretty plausible, then, that the resurrection hypothesis renders the evidence less improbable that it would otherwise be, and that’s all that’s required, according to Bayes theorem, for there to be evidence for the resurrection hypothesis.

But that doesn’t mean, by any stretch of the imagination, that we should believe in the resurrection. Perhaps the evidence for the resurrection is strong enough to get the probability up from one in a trillion to one in a billion; this still ends up not being a hypothesis we should take seriously. Both Ehrman and Licona agreed that a skeptic about the resurrection needs to have some alternative hypothesis to explain the evidence. That’s simply not true. If we’re dealing with an event that ends up, even after the evidence has been taken into account, being very improbable, then it’s quite rational to say ‘I don’t know what happened, but that didn’t happen.’

To be fair, Erhman did press the old Carl Sagan line ‘Extraordinary events require extraordinary evidence’, arguing that the resurrection is very improbable because it would require violating a law of nature.* But without bringing in Bayesian notions, this is just a rhetorical slogan, and it ended sounding like Ehrman took naturalism to be unfalsifiable. The only mention of Bayes in the whole six hours was Licona saying that evidence can overcome low prior probabilities. That’s right, in principle. But given that, what this debate should have been about is:

(A) What is the prior probability?

(B) How strong is the evidence?

(C) What probability do we end up with as a function of (A) and (B)?

Because they didn’t engage with the Bayesian framework, this discussion spent six hours getting nowhere.

Improbable things happen. And when they do, we often end up with evidential support for whacky hypotheses. If Christian apologists want to make a case for the resurrection of Jesus, then they need to argue for a worldview in which the resurrection of Jesus should be assigned a non-negligible prior probability.

*Actually, I was more on Lacona’s side on the specific point of whether a miracle would violate the laws of nature. That’s because I follow my colleague Nancy Cartwright in conceiving of the the laws of physics as ‘ceteris paribus’ laws, which tell us what would happen in the absence of other causal factors. I’m to be arguing with Sean Carroll about this (again!) on next month’s Mind Chat.

Are There Objective Values?

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A lot of my Twitter debating time recently has been spent defending the claim that there are facts about value that hold independent of our desires. The example I always press is that there is an objective distinction between things that are worth doing (e.g. pursuing pleasure, learning, being creative) and things that are pointless (e.g. counting blades of grass, for its own sake, when you don’t enjoy it or get any further good from it). In order to set out my case and debate it a bit, I cheekily invited myself on Kane B’s YouTube channel (he has the opposing view) and we had a really good chat about it:

In hindsight, I think there’s one argument I briefly raised that I should’ve pressed more. I have two kids. Suppose the older one of them grows up to hate philosophy and love football. Now, I hate football and love philosophy. Suppose I really worry about my elder child’s preferences, even though she’s clearly very happy, and I try to talk her round, even suggest therapy to try to align her preferences to mine. I think we’d all think my behaviour would be deeply unreasonable: I’d just be imposing my personal preferences on her.

But now suppose my younger child grows up to have the basic goal of counting how many yellow cars there are in our neighbourhood every day. Suppose this really makes her really unhappy (t takes several hours) and often unwell (it’s very tiring, and she does it even when the weather is really bad), but it’s her only main freely chosen goal in life, and it’s not among her life-goals to be healthy or happy. Now in this case, if I really worry, try to talk her around, maybe suggest therapy, I think we’d think my behaviour was understandable and reasonable.

Why the difference? In both cases, the child is pursuing a freely chosen goal. The younger child is miserable and unhappy, but if there are no objective value facts, then pursuing health and happiness are just as arbitrary goals as counting yellow cars. Surely, then, my concern with the younger child should be seen as me imposing my values on her just as much as in the case of the older child? Or at least, that is what we should think if we deny the existence of objective value.

Kane claimed not only that he doesn’t believe that some goals and more worthwhile than others, but that he just doesn’t even feel the intuition. I suggest that someone who differentiates between these two cases in a normal way is implicitly committing to objective values. They are effectively committing to the idea that there’s something objectively problematic about not being concerned with your own health and happiness; it’s this implicit assumption that explains why we think concern and intervention is reasonable with the younger child but not the older. If we totally don’t feel the pull of the intuition that there are objective values, then we should be mystified by the intuition that my treatment of the younger child is somehow ‘more reasonable’. But is anyone really mystified by this?

We could put the argument like this:

  1. Anyone who would judge concern and intervention is reasonable in the case of the younger child but unreasonable in the case of the older child implicitly believes in objective values.
  2. Almost everyone would judge concern and intervention reasonable in the case of the younger child but unreasonable in the case of the older child.
  3. Almost everyone implicitly believes in objective values.

It’s a further question as to whether this belief is justified (I try to argue that it is in the video), but the case I’m trying to make here is that many people who think they don’t believe in objective values, in fact do.

Genuinely interested in hearing from value anti-realists on what they think about this case.

A Surprise Point of Agreement With Sean Carroll

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I’ve had some great philosophical interactions with Sean Carroll, of late. I was on Sean’s podcast a while back, and more recently he kindly contributed to a volume of essays responding to my book Galileo’s Error: Foundations for a New Science of Consciousness (I counter-responded to all of the essays, including Sean’s, here). We then debated this for three hours on the Mind Chat podcast I host with Keith Frankish. Finally, Sean wrote this blog post summarising his reflections on the Mind Chat discussion.

At the end of the post, Sean conceded that, if panpsychism is true, consciousness underlies my behaviour in the same way that the hardware of my computer underlies its behaviour. However, he then went on to make a surprising statement: because of substrate independence, the panpsychist can’t claim that ‘consciousness gets any credit at all for our behavior in the world.’

Why not? I really don’t get where Sean’s coming from here. The term ‘substrate independence’ just means that the same function can be realised by different hardware. It certainly doesn’t mean that hardware doesn’t do anything! If my consciousness underlies my behaviour in the same way the hardware of my laptop underlies Microsoft Word, that’s as much of a causal role for consciousness as anyone could reasonably want.

I’m so glad Sean and I ended on a point of agreement: consciousness does ground behaviour on a panpsychist worldview.

Can Calculators Add? Can Brains Add?

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Suppose you had a rubbish that calculator that could only deal with numbers below 100. Assuming that, apart from that limitation, it behaved as calculators normally behave, you’d naturally interpret it as performing the addition function when you type in ‘1+1’ and get the answer ‘2’. But is it? Consider the following mathematical function, which, following the philosopher Saul Kripke, I will call ‘quus’:

QUUS: The quus function is just like the plus function when the numbers inputted are below 100, but when any of the numbers inputted are above 100, the output of the function is 5.

Given that the rubbish calculator can’t deal with numbers above 100, there’s no fact of the matter as to whether it’s performing the plus function or the quus function. So we can’t really say that the calculator is adding. Rather, it’s indeterminate whether it’s adding or quadding.

Okay, but we can still say that normal calculators add, right? I’m afraid not. Once we’ve conceded the above, essentially the same point is going to apply to all calculators. That’s because, for any calculator, there’s going to be some number N that is too huge for that calculator to deal with. And so we can just define the quus function in terms of N, yielding essentially the same problem:

QUUS*: The quus* function is just like the plus function when the numbers inputted are below N, but when any of the numbers inputted are above N, the output of the function is 5.

For the calculator in question, given that it can’t deal with numbers bigger than N, there’s no fact of the matter as to whether it’s performing the plus function or the quus* function. We cannot definitely say that the calculator is adding rather than quadd*ing!

Does any of this matter? As long as we get the right answer when we’re doing our accounts, who cares about the deep metaphysics? I don’t think the above would be of deep interest if it was just a problem for calculators. Things start hotting up when we ask whether the same problem applies to us. Can our brains add?

You might see where this is going. There is going to be some number so huge that my brain can’t deal with, and if we define the quus function in terms of that number, we’ll reach the conclusion that there’s no fact of the matter as to whether my brain is performing the plus function or the quus function.

The trouble is there certainly is a fact of the matter as to whether I perform the plus function or the quus function. When I do mathematics, it is determinately the case that I’m adding rather than quadding. It follows that my mathematical thought cannot be reducing to the physical functioning of my brain. We could put the argument as follows:

  1. If my mathematical thought was reducible to the physical functioning of my brain, then there would be no fact of the matter as to whether or not I performed the plus function or the quus function when I do maths.
  2. There is a fact of the matter as to whether or not I perform the plus function or the quus function when I do maths.
  3. Therefore, my mathematical functioning is not reducible to the physical functioning of my brain.

The problem is that conscious thought, e.g. about mathematics, has a specificity that finite physical mechanisms cannot deliver.

This is just one of the deep problems raised by what philosophers call cognitive phenomenology: the distinctive kinds of experience involved in thought. It’s broadly agreed that there is a ‘hard problem’ of consciousness. But when people think about consciousness, they tend to think about sensory consciousness, things like colours, sounds, smells and tastes. But consciousness also incorporates conceptual thought and understanding, and these forms of experiences raise distinctive philosophical challenges of their own. I believe that we’re not even at first base in appreciating, never mind addressing, the challenges raised by cognitive consciousness. If you thought it was hard to explain the feeling of pain, you ain’t see nothing yet!

Happy Christmas!

Materialism Remains the Majority View…But Only Just!

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The 2020 PhilPapers Survey of Anglophone academic philosophers’ views has just been published. On the philosophy of mind, physicalism (AKA materialism) remains the view of the majority, but only just, with 51.9% of philosophers professing to accept/lean towards physicalism about the mind. However, a very large minority of 32.1% align with non-physicalism about the mind (15.9% are undecided, accept an alternative to both, or think the question is too unclear to answer*). There was also a more specific question on ‘Consciousness’ which allows us to dig a bit deeper. Among those who accept/lean towards non-physicalism, approximately 3/4 are dualists and 1/4 are panpsychists.

How do I feel about these results? I didn’t doubt that materialism would come out the most popular position, although I hoped it would be under 50% this time. I was also hoping that, among non-physicalist positions, panpsychism and dualism would be a bit closer to 50/50. However, panpsychism did not even feature in the 2009 survey: it’s gone from being a view that hardly anyone took seriously option to being one of the standard options to consider.

There’s a prima facie inconsistency in the data. The ‘Other Minds’ questions asks which things are conscious, and only 2% accepted/leaned towards particles being conscious, a much lower percentage than accept/lean towards panpsychism in the ‘Consciousness’ question. I suspect this is because when addressing the ‘Other Minds’ question, people were generally considering what is suggested by the empirical data concerning the neural correlates of consciousness, whereas when addressing the ‘Consciousness’ question, people are giving their opinion on the best solution to the hard problem. The case for panpsychism is built on the latter not the former.

Of course, ultimately this isn’t a popularity contest. I think there are good reasons to take panpsychism to be the most plausible option, and those reasons would still be there even if nobody accepted them. But it’s nice to see that the Anglophone philosophical community is very slowly inching its way towards the truth 😉

Incidentally, the only view of consciousness less popular than panpsychism was eliminitivism, the view of Daniel Dennett and others that consciousness doesn’t really exist.

*A smaller % of the ‘other’ accept a combination of the two, think there is no fact of the matter, or reject all of the above.

The Multiverse for Breakfast

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I’m really looking forward to my first in person philosophy talk since the start of Covid, which will take place at the ‘How the Light Gets In‘ festival’ Sunday 19th March. It’s a festival of philosophy and music, which is going to be held in the glorious grounds of Kenwood House on Hampstead Heath in London. I’m going to talk about the science of consciousness, and how the supposedly ‘easy problem’ of establishing neural correlates of consciousness is actually harder that the ‘hard problem’. I’ll also outline a couple of ways forward.

I used to sing in a band in my teens and 20s, performing ‘guitar explorations of the human condition’. But then everyone had babies and we haven’t played for ages. Because this festival does music as well as philosophy, I tried my luck and asked if my band could play. To my surprise, they said yes! So we’re hurriedly trying to remember the songs…worried I’m too old for this caper…

I’m also doing a few other events on the Sunday: breakfast chatting about fine-tuning and the multiverse, a neuroscience and consciousness school with Joanna Bryson, and a panel on the small topic of ‘Life, the Universe and Everything’. I’ve listed all the events I’m doing below.

Most of all, I’m really looking forward to chatting about philosophy in person again…come along if you can!

Saturday 18th

– 6:30pm: ‘Number and Number’ (my band) will perform in the ‘Stage’ venue

Sunday 19th

– 9am: Philosophy Breakfast on Cosmological fine-Tuning and the Multiverse

– 12pm: IAI School with Joanna Bryson – Neuroscience and Consciousness

– 2pm: Solo talk – The Many Voices of Consciousness

– 5.30pm: Life, The Universe and Everything panel

Tickets available here:

19 Essays on ‘Galileo’s Error’

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In October, there will be a special issue of the Journal of Consciousness Studies consisting of 19 essays responding to my work (by scientists, philosophers, and theologians) and one essay in which I respond to these essays. My response also discusses what a post-Galilean science of consciousness might look like. Ten of these essays (including the introduction, which gives an overview) are already online, and are linked to in the contents below:

  1. Introduction, by Philip Goff and Alex Moran

The Scientists

  1. Carlo Rovelli – ‘Relations and Panpsychism,’ Centre de Physique Théorique de Luminy, Aix-Marseille University.
  2. Sean Carroll – ‘Consciousness and the Laws of Physics,’ California Institute of Technology and Sante Fe Institute
  3. Lee Smolin & Clelia Verde – ‘Physics, Time and Qualia,’ Perimeter Institute of Theoretical Physics
  4. Anil Seth – ‘The Real Problem(s) with Panpsychism,’ Sackler Centre for Consciousness Science, University of Sussex, Programme for Brain, Mind and Consciousness, Canadian Institute for Advanced Research
  5. Christof Koch – ‘Reflections of a Natural Scientist on Panpsychism,’ Allen Institute for Brain Science in Seattle
  6. Jonathan Delafield-Butt – ‘Autism and Panpsychism: Putting process in mind,’ University of Strathclyde
  7. Robert Prentner – ‘Dr Goff, Tear Down This Wall! The interface theory of perception and the science of consciousness,’ Center for the Future Mind, Florida Atlantic University
  8. Chris Fields – ‘What is a Theory of Consciousness For?,’ independent researcher

The Philosophers

  1. Luke Roelofs – ‘Is Panpsychism at Odds with Science?’ New York University
  2. Annaka Harris – ‘A Solution to the Combination Problem and the Future of Panpsychism,’ New York Times bestselling author.
  3. Keith Frankish – ‘Galileo’s Real Problem,’ Sheffield University.
  4. Michelle Liu – ‘Qualities and the Galilean view,’ University of Hertfordshire
  5. Alex Moran – ‘Grounding the Qualitative: A New Challenge for Panpsychism,’ Oxford University
  6. Alyssa Ney – ‘Panpsychism and the Limits of Physical Science,’ UC Davis
  7. Damian Aleksiev – ‘Missing Entities: Has Panpsychism Lost the Physical World?’ Central European University
  8. Ralph Weir – ‘Can Post-Galilean Science of Consciousness Avoid Substance Dualism?’ University of Lincoln
  9. Galen Strawson – ‘Oh, You Materialist!’ University of Texas at Austin

The theologians

  1. Joanna Leidenhag – ‘Why a Panpsychist Should Adopt Theism: God, Galileo and Goff,’ University of St Andrews
  2. Sarah Lane Ritchie – ‘Panpsychism and Spiritual Flourishing: Constructive Engagement with the New Science of Psychedelics,’ University of Edinburgh

Replies from Philip Goff

  1. Putting Consciousness First’ University of Durham

The ‘Free Speech Union’ opposes the right of athletes to take the knee. You’d almost think they didn’t really care about free speech.

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As a philosopher, I like to use thought experiments. Suppose a BBC newsreader tweeted that there were more and more black families moving into their area and it was really bringing down the tone of the neighbourhood. I don’t know about you, but I’d be outraged. I’d probably want to express my outrage through social media, and I’d enthusiastically sign a petition to get that newsreader sacked from their job. This seems like a totally normal reaction to someone in a position of public responsibility making such an abhorrent statement.

Would that make me part of the ‘woke mob’ intent on destroying free speech that many on the right of politics have been railing against of late? The intro video on the ‘Free Speech Union’ (FSU) website presents the firing of Danny Baker for tweeting an image of a couple with a chimp to accompany the birth of the first mixed race royal baby as an example of suppressing free speech. But was Baker’s tweet any less abhorrent than the tweet of my imagined newsreader? I suspect Toby Young – Secretary General of the FSU – would argue that it is. He’d be free to do so. But those who do find that tweet deeply morally abhorrent are also free to express their view and to lobby for consequences. That’s how free speech works. What is singularly lacking from the FSU is a consistent and principled policy on when moral outrage is and is not warranted.

The right-wing free speech warriors are also pretty inconsistent about real world cases of free speech infringement. There wasn’t much to be heard from these valiant heroes when the General Secretary of the Labour party barred MPs and Labour party members from discussing Jeremy Corbyn’s suspension – a literal ban on free speech. Nor when an outraged mob of 26 MPs and 2 peers took their pitchforks to the National Trust for daring to produce a report on the links between the Trust’s properties and the slave trade. And when the government took the scarily authoritarian step of ordering schools not to use resources from organisations opposed to capitalism? Not a peep. It seems that their concern with free speech is conditional on what is being said.

This blatant lack of consistency was also apparent recently when Deputy Research Director of the Free Speech Union Emma Webb went on Talk Radio to express her support for the decision of the International Olympic Committee to ban athletes from taking the knee. Webb seemed not even to register the tension in a campaigner for free speech advocating the quashing of free expression. I tweeted about this, and actually received a polite response from Webb. For some reason, however, Webb deleted her response to me a short while later. In the absence of someone to talk to on twitter, I decided to write this article instead.

Webb defended her position by saying that her point was that rule 50 – that ‘no kind of demonstration or political, religious or racial propaganda is permitted in any Olympic sites, venues or other areas’ – was being consistently applied, and that what she had said was consistent with thinking that rule 50 should be scrapped. However, what Webb actually said in the interview was that the committee’s action was the ‘right decision’, not merely that it was a consistent application of rule which may or not be a good one. If I said that the Taliban’s decision to stone a particular individual for adultery was ‘the right decision’, it would be reasonable to interpret me as asserting not merely that they were consistently applying a law, but that that law was appropriate. Why would anyone bother to praise the consistent application of a rule they didn’t agree with?

Indeed, Webb went on to defend rule 50, on the basis that 70% of athletes surveyed wanted to keep the rule. Do the FSU decide all of their policies based on surveys of non-members? Wouldn’t it be better to defend a principled stance of their own? Perhaps the Free Speech Union could develop a consistent policy that there should be safe spaces where sensitive souls can be protected from certain kinds of speech. But it would take some work to make that consistent with Toby Young’s attack on a workplace in which football talk was banned from the work environment. It’s all a bit of mess.

If at any point the FSU is interested in formulating a coherent statement on what they stand for, I’d recommend taking some time to reflect on the important distinction between ‘freedom of speech’ and ‘having a platform.’ Most of the so-called infringements of free speech they focus on are actually just instances of people being declined a platform. The fact that I don’t have as many twitter followers as Toby Young doesn’t mean my speech is being curtailed. That’s not to say there aren’t important ethical issues regarding who gets a platform. We surely want a range of views to be aired, and minority voices to be heard. But if that’s really your concern, then you’d make better use of your time focusing on issues of media plurality. You might, for example, be concerned with the fact that there are hardly any trans columnists at our national newspapers. And you would certainly be worried that exploitation of the UK’s antiquated libel laws might be about to destroy the only radical left print magazine left in this country.

It’s not for me to look into the hearts of Young and Webb, to judge whether their motives are pure. But my job is to spot incoherence and inconsistency, and I can see a mile off that the policy platform of the FSU needs a lot of work. I wish them well and would be happy to offer philosophical consultancy at a modest fee. But if they are serious about developing a consistent stand on free speech, then they should be prepared to find themselves in a very different Free Speech Union from the one that exists today.

The Lottery Fallacy, Fine-Tuning, and the Multiverse

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Our best current science suggests that our universe is fine-tuned for life. That is to say, certain numbers in basic physics – e.g. the strength of gravity, the mass of electrons, etc. – are, against improbable odds, exactly as they need to be for life to be possible. Many scientists and philosophers think this is evidence for a multiverse, but I disagree. What we have evidence for us that our universe is fine-tuned and postulating a huge number of other universes doesn’t explain this.

I recently wrote a Scientific American article on this, and there have been two blog posts from Skeptics Guide to the Universe in response. Earlier this week, host Steve Novella and I got together to discuss the issue, and an edited version of our discussion will be going up on their podcast tomorrow. The discussion prompted me to clarify my argument in my own mind, and I’d like to share here how I’m thinking about it now.

Steve accuses me of committing the lottery fallacy. But what is the lottery fallacy? Suppose against improbable odds my lottery numbers come up. Clearly there’s something going wrong if I think there needs to be some special explanation of the fact that I won. Steve suggests that the error consists in focusing on the particular person who won – Philip Goff – rather than merely the fact that someone won. Similarly, by focusing on the fact that our universe – rather than just some universe – is fine-tuned, he thinks I’m committing the same fallacy.

I don’t think this is the right explanation of the lottery fallacy. Sometimes a focus on the particular person is appropriate. Suppose, for example, that the partner of the person who picked the numbers wins on a billion to one odds. Then it does seem we want to focus on the particular person who won.

What’s the difference between the two cases? The fact that Philip Goff won the lottery is improbable, but it’s not improbable that it happened by chance. Why is that? Because there’s no (non-ad hoc) non-chance hypothesis that would render it much more probable. Whereas when it comes to the fact that the partner of the person who picked the numbers won, this is just as improbable as Philip Goff winning, but in this case it’s not only improbable but improbable that it happened by chance. Why? Because there is a (non-ad hoc) non-chance hypothesis that would render it more probable, namely the hypothesis that there was collusion between the person who chose the numbers and her partner. Assuming that hypothesis, it’s much more likely that the partner would win that it is on the hypothesis that the numbers were picked randomly.

What about the fine-tuning case? I think we’re struck by the fine-tuning not because it’s improbable – whatever numbers had come up would be equally improbable – but because it’s improbable that it happened by chance. And, again, this is because there’s a non-chance hypothesis that would render it much more probable, namely the hypothesis that considerations of value were involved in determining the values of the constants. If the process that determined the constants was sensitive to the value of the resulting universe, then it wouldn’t be surprising that the constants would end up fine-tuned, much less surprising that it would be if they were selected at random.

So I don’t think the lottery fallacy is anything to do with focusing on the particular individual rather than the general fact; rather it’s a matter of fallaciously inferring from the fact that something is improbable to the fact it’s improbable that it happened by chance. But the fact that our universe in fine-tuned is not only improbable, it’s also improbable that it happened by chance. Therefore, focusing on the fact that our universe is fine-tuned – rather than that some universe is fine-tuned – does not commit the lottery fallacy.

So that’s why I don’t agree with Steve’s argument against my position. Let me try a different way of making the case for my position (this is a modified form of the argument White defends in the postscript to a reprint of this article). We can only gain support for a hypothesis with the evidence we in fact have. We can either think of evidence as our actual observations, or as the concrete, physical states of affairs we know about through observation. Whether you think of the fine-tuning evidence as our actual observations, or you think of it as the concrete fine-tuned physical universe we live in, in either case our evidence is not made more probable by the multiverse hypothesis. Yes, the existence of some fine-tuned universe is made more probable by that hypothesis. But we have to work with the evidence we in fact have, and the evidence we in fact have is constituted by the properties of this concrete, physical universe (or our observations of it), and this is not made more probable by the multiverse hypothesis

Many people have worried about the Joker analogy I make in my Scientific American article, on the grounds that, in this thought experiment, you pre-exist the flukey event. In the discussion I had with Steve, I got around this with a different thought experiment. Suppose your conception came about through IVF. And suppose you discover as an adult that when the doctor fertilised the egg, she rolled twenty dice to see whether she’d do it, committing only to fertilise the egg if they all came up sixes. Does your discovery that your birth was dependent on this improbable event provide you with evidence that the doctor did the same in many other IVF cases, rolling dice to decide whether to fertilise the egg? I don’t think so; all you have evidence for is that your conception was decided in this way, and whether or not the doctor did this in other cases has no bearing on how likely it was that the right numbers would come up with your conception. By analogy, all we have evidence for is that the right numbers came up for our universe, and whether or not there are other universes has no bearing on how likely it was that the right numbers came up for our universe.

In correspondence after our discussion, Steve proposed tweaking the thought experiment: suppose I’m considering whether the doctor rolled dice many times or only once to decide whether to fertilise the egg that made me. I agree in that case you would have evidence for that hypothesis, as that hypothesis makes *your* existence more likely, and your existence constitutes your evidence. But that modified IVF hypothesis corresponds to a sci fi scenario in which our universe had a number of shots at fixing its constants (i.e. random processes reset them numerous times) and the Guardian of the Universe only allowed it to proceed if they came up fine-tuned. That hypothesis would make our evidence (our fine-tuned universe) more likely. But that’s not the multiverse hypothesis. According to the standard multiverse hypothesis (eternal inflation + string theory) our universe had only one shot at fixing its constants. That corresponds to a scenario in which there is only one dice roll to determine whether the egg that produced you gets fertilised.  

In our discussion, Steve came up with another thought experiment. Suppose the mischievous god Loki has just brought you into existence, and he tells you that he rolled twenty dice to decide whether or not to create a person, committing only to create a person if they all came up six (I’ve modified the example a little to make it similar to mine, but the substance is the same). Do you have grounds to think Loki has done this many times, on the assumption that each time he creates a person it’s a distinct person? I admit I did have to think about this one, and my intuitions are less firm that in the IVF case. So we need an explanation of why intuitions are different in these two cases. I suggest it’s because in the IVF case, it’s totally clear that the hypothesis I’m considering is one in which other babies would be born who aren’t me, whereas in the Loki case, it’s easy to slip into thinking he’s been having lots of shots at creating me. If I’m considering the scenario in which Locki had numerous shots at creating me, then I do find evidential support. But this is analogous to the tweaked IVF thought experiment in which the doctor rolled dice numerous times to decide whether to create me, and, as I argued above, this does not mirror the real-world fine-tuning case.

In summary: the fine-tuning is very puzzling, but it’s not evidence that we live in a multiverse.

Does Quantum Mechanics allow for Free Will?

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Do the laws of physics rule out free will? Neuroscientist Kevin Mitchell has a recently argued (paper and blog post):

  • If the laws of physics are deterministic, then free will is ruled out
  • If the laws of physics are indeterministic, then this makes room for the reality of free will.

It’s a really interesting paper but I have some disagreements, which I would like to outline here.

A quick preliminary remark: there is a huge debate in philosophy as to whether or not human freedom is compatible with determinism (we can define determinism as the thesis that the initial state of the universe, in conjunction with the laws of nature, determine everything that will happen subsequently). Compatibilists believe is that free will and determinism can happily co-exist. Mitchell is well aware of this debate, and briefly motivates his commitment to incompatibilism: that view that if the universe is determined, we’re not really free. For the purposes of this blog post I will assume incompatibilism.

Given the assumption of incompatibilism, Mitchell argues that the way to avoid the clash between freedom and indeterminism is to embrace the indeterminism entailed by many interpretations of quantum mechanics. Now, many have pointed out that mere randomness isn’t what we need to make sense of freedom, and Mitchell acknowledges this. But he thinks that the absence of total determinism in fundamental physics provides some ‘causal slack’ that mental processes at the neurophysiological level can then take advantage of:

“The inherent indeterminacy of physical systems means that any given arrangement of atoms in your brain right at this second, will not lead, inevitably, to only one possible specific subsequent state of the brain. Instead, multiple future states are possible, meaning multiple future actions are possible. The outcome is not determined merely by the positions of all the atoms, their lower-order properties of energy, charge, mass, and momentum, and the fundamental forces of physics. What then does determine the next state? What settles the matter?”

Mitchell’s answer this posed question is the agency of the organism: physics leaves certain options open, the organism then decides from among those options.

It sounds intuitive, but I don’t think this strategy ultimately works. Even among indeterministic interpretations of quantum mechanics, although the physics doesn’t conclusively settle what will happen, it does determine the objective probability of what will result from any given physical circumstance. Although we can’t predict with certainty, say, where a given particle will be located when we make a measurement, the Born rule tells us, for any given location in the universe, precisely how likely we are to find the particle in that location. It’s not determinism, but it’s not a ‘free for all.’

Mitchell worries that if the physics determines what I’m going to do, then I’m not really free. But physics determining the objective probability of what I will do is no less constraining. If whether I water Susan (my Madagascan dragon tree) is really up to me – in the strong incompatibilist sense – then surely the physics can’t fix how likely it is that I will water Susan. If it’s just totally up to me, then it could go either way depending on my radically free choice.

Here’s a little thought experiment to make the point clear. Take the moment when I’m about to decide whether or not to water Susan. Let’s say the Born rule determines that there’s a 90% change my particles will be located in the way they would be if I watered Susan and a 10% chance there’ll be located in the way that corresponds to not watering Susan (obviously this is a ludicrously over-simplistic example, but it serves to make the point). Now imagine someone duplicated me a million times and waited to see what those million physical duplicates would decide to do. The physics tells us that approximately 900,000 of the duplicates will water Susan and approximately 100,000 of them will not. If we ran the experiment many times, each time creating a million more duplicates and waiting for them to decide, the physics tells us we would get roughly the same frequencies each time. But if what happens is totally up to each duplicate – in the radical incompatibilist sense – then there ought to be no such predictable frequency. The number that do and don’t water the plant should change each time, as the radically free choices of each individual varies.

In other word, indeterministic quantum mechanics doesn’t provide the kind of causal slack Mitchell is seeking. The problem is that objective probabilities constrain our choices as much as deterministic laws. After all, a deterministic law is just a law that yields an objective probability of 1 that a given outcome will occur.

All is not lost, however. I think Mitchell is conflating two claims:

  • The laws of physics are deterministic
  • The universe as a whole is deterministic

How could these come apart? They come apart if the laws of physics are ceteris paribus laws, i.e. laws that tell us what will happen in the absence of other causal influences. On this interpretation of physical law, the probabilities yielded by the Born rule are the objective probability of what will occur in the absence of some other causal influence. Such other causal influences might include the kind of irreducible causal powers Mitchell believes reside at the level of neurobiology. Mitchell seems to be concerned to avoid a violation of the laws of physics. But if the laws of physics are ceteris paribus laws, then higher-level causal powers should be thought of as complementing the laws of physics rather than contradicting them. If physics basically tells us ‘X will happen unless there are some higher-level causal forces,’ and X doesn’t happen precisely because there are higher-level causal forces, then nothing occurs that is inconsistent with physics.

It does not follow that there are no empirical challenges for a proponent of incompatibilist free will. Some philosophers have argued that we have strong empirical grounds for thinking there are no irreducible causal influences of the kind Mitchell believes in, that everything that happens at higher levels can be reduced to the causation we find in physics. But this is an empirical question about neurobiology. My point here is just that the question of whether the laws of physics are deterministic has no bearing on the question of whether the universe as a whole is deterministic, and hence no bearing on the question of whether or not we have free will.