Phillip Goff writes in Aeon
Suppose we walk into a casino and the first person we see, call her Sammy Smart, is having an incredible run of luck, calling the right number in roulette time after time. I say: ‘Wow, the casino must be full tonight.’ Naturally, you’re puzzled and you ask me where I’m getting that idea from. I respond: ‘Well, if there are a huge number of people playing in the casino, then it becomes statistically quite likely that at least one person in the casino will win big, and that’s exactly what we’ve observed: somebody in the casino winning big.’
This is silly. If we walk into a casino and see lots of people, then we think it is crowded. Seeing one guy winning or losing tells us nothing at all.
Everyone agrees that the above is a fallacious inference, and the reason it’s fallacious is that it violates the total evidence requirement. There are two ways of construing the evidence available to us as we walk into the casino:generic evidence: someone in the casino has had a great run of luck; or
specific evidence: Sammy Smart has had a great run of luck.
Nonsense! Sammy may be a 'shill' or else this casino is a front for money laundering. Total evidence means total relevant evidence. The evidence of the casino being crowded is given by finding lots of people squeezed around its gambling tables. Suppose we can't get into the Casino. Then we may have to be content with observations re. how many are entering and leaving it. True, we can't be sure they are gambling in the Casino rather than visiting a secret brothel they may have built in the basement.
In the above scenario, my strange reasoning essentially involved working with the generic way of construing the evidence: it is indeed more likely that someone in the casino had a great run of luck if we hypothesise that there are many people playing well in the casino.
No it isn't. If you saw lots of people crowded around the very first table in the casino, then you might think the casino must be crowded though you would still want to sample more rooms in it.
But, again, the total evidence requirement obliges us to work with the more specific way of construing the evidence – Sammy Smart had a great run of luck – and, once we do this, the inference to a full casino is blocked: the presence or absence of other people in the casino has no bearing on whether or not Sammy Smart in particular will play well. The reasoning employed by the multiverse theorist makes exactly the same error. To respect the total evidence requirement, we need to work with the specific version of the evidence – that this universe is fine tuned – and the presence or absence of other universes has no bearing on whether or not this universe in particular turns out to be fine tuned.
How do you know you have walked into a Casino or that Sammy Smart is playing roulette? The answer is it is because you know there are many Casinos and roulette wheels all over the world. If you see a guy winning big on the very first table, you may suspect that the thing has been staged so as to put punters in an optimistic frame of mind.
The multiverse theory is like Darwin's theory of evolution. I say 'God created us in his image. That's why my fingers are so suited to typing this on my key-board.' You reply that keyboards were invented to fit our fingers and those fingers evolved from those of some type of ape. God had nothing to do with it. Similarly, if a physicist says 'God must have 'fine-tuned' our Universe', other physicists can reply, 'not necessarily. The thing could have happened by chance. Just as there are planets without life, so there may be other Universes without life.'
Many argue that this is where the anthropic principle kicks in. While we could have entered the casino and observed someone rolling badly, we could not have observed a universe that wasn’t compatible with life.
We can observe planets without life. It may be that some galaxies are too young or too old or have some other property such that astronomers will declare them to be devoid of life. Why should the same not apply to other Universes which coexist with our own? The fact is, we can't interact with stuff in our own Universe which is outside our 'light cone'. What's so wrong with saying there may be universes separate from our own?
But isn’t there independent scientific evidence for a multiverse? Yes and no
It is of course trivially true that we could not have observed a universe incompatible with the existence of life.
We have observed planets without life. Why should there not be Universes without life? What is relevant is the Maximum Uncertainty Principle- viz for any event, if there are multiple reasonable values that an uncertain measure may take, then the value as close to 0.5 as possible is assigned to the event. Currently we think we can have no evidence of the existence of other universes (though this may be changing) and so we are obliged to say the thing is as probable as it is improbable.
But no theoretical justification has ever been given as to why this would make it OK to ignore the total evidence requirement.
There can be no evidence. So the maximum uncertainty principle applies.
Moreover, we can easily insert an artificial selection effect into the casino example by imagining there’s a sniper hidden in the first room of the casino, waiting to kill us as we enter unless there is someone in the first room having an extraordinary run of luck.
But that sniper has already been poisoned by the evil cocktail waitress and so he dies before he can squeeze off the shot.
With this in place, the casino example is relevantly similar to the real-world case of fine-tuning: just as we could not have observed a universe with the wrong numbers for life, so we could not have observed a player rolling the wrong numbers to win. And yet, nobody disputes that the casino example involves flawed reasoning, reasoning that, in my view, is indiscernible from that of the multiverse theorist.
The two are wholly unconnected. It is crazy to think a Casino is crowded if all you have observed is one punter. It is irrelevant whether he is winning or losing or trying to seduce the cocktail waitress. The multiverse theorist is more likely to be right than wrong because we now know there are planets without life. It is possible there are galaxies without life. Moreover our galaxy may cease to support life. It is no big stretch to say there may be other Universes without the 'fine tuning' for life.
But isn’t there independent scientific evidence for a multiverse? Yes and no. There is tentative support for what cosmologists call ‘inflation’, the hypothesis that our universe began with a short-lived exponential rate of expansion. And many physicists have argued that, on the most plausible models of inflation, the exponential expansion never ends in reality considered as a whole, but ends only in certain regions of reality, which slow down to become ‘bubble universes’ in their own right. On this model, known as ‘eternal inflation’, our universe is one such bubble.
There may be entanglement between such bubbles. It would be cool if we could import energy from some such empty bubble.
The problem is that there are two possible versions of eternal inflation: heterogenous eternal inflation – when a new bubble forms, probabilistic processes determine that the values of the constants, and so the vast majority of bubble universes, are not fine tuned; or
homogenous eternal inflation – the values of the constants do not vary between bubble universes.
If we have no evidence either way then the Maximum Uncertainty Principle applies. However, there does seem to be some evidence for the heterogenous hypothesis. This is because cosmic inflation appears to have been irregular which is why there are fluctuations in cosmic background radiation.
Pretty much all multiverse theorists assume heterogenous eternal inflation, which is probably because only this version can have a hope of explaining away fine-tuning. Only if there’s enough variety in the ‘local physics’ of different bubble universes does it become statistically likely that the fine-tuning is just a fluke. But there is zero empirical evidence for this.
In which case 'total evidence' is zero and maximum uncertainty applies. What tips the balance in favour of the multiverse theory is the fact that no mechanism for fine-tuning has been suggested. Thus we may as well believe that chance determines everything.
Moreover, if we respect the total evidence requirement, then the fine-tuning itself is powerful evidence against heterogenous eternal inflation.
The fact that I can type this on my keyboard proves God is a blogger- right? Fine-tuning is merely something some of us discern and find remarkable. God must wear spectacles because what are the chances our faces would have noses and ears so conveniently located for spectacle frames?
Remember that the total evidence requirement obliges us to work with the specific way of construing the evidence of fine-tuning: specific evidence: this universe is fine-tuned.
Why stop there? My farts are very fine tuned indeed. They have destroyed my social life- which is what God wants because he can't get enough of my blog.
According to our standard mathematical way of defining evidence – known as the Bayes theorem –
Nonsense! Evidence in maths is a deductive proof from axioms. There may be evidence for axioms and this is important in applied fields. Bayes is about conditional probability. But probabalistic reasoning can be discarded once we have empirical confirmation. After the Eddington expedition, mathematicians had to accept that Einstein was right.
we ought to go for the hypothesis that makes our evidence most probable.
No. We accept evidence once repeated experiments arrive at the same conclusion.
If heterogenous eternal inflation were true, it would be incredibly unlikely that our universe would be fine tuned, as the probabilistic processes that fix the constants of each universe are entirely random.
This is like saying it is incredibly unlikely that life exists. Therefore we don't exist. Statistically speaking, it may be that a few billion years from now, there will be almost zero evidence that we ever existed. But we did exist.
But if we combine homogenous eternal inflation with some form of cosmic goal-directedness towards life, then it becomes massively more likely that our universe will be fine tuned.
Why stop there? Why not speak of the goal directedness of the atoms which constitute my farts? You can't tell me God didn't intend me to fart so frequently and so foully that everybody would run away from me and thus I'd be doomed to blogging stupid shite.
In other words, even if we adopt the eternal inflation multiverse, the evidence of fine-tuning still pushes us towards cosmic purpose.
My farts will push you away from God's cosmic purpose for my existence.
The Christian philosopher William Lane Craig has argued that, if the universe has no purpose, then life is meaningless.
If my farts aren't God's way of securing me the solitude and boredom required for the pursuit of Socioproctology, then my life is indeed meaningless. You may disagree. My life serves a purpose if I die horribly of some new disease which my autopsy reveals. In death, I may help advance medical science. Anyway, it is this forlorn hope which has me ignobly cling to a wholly worthless life.
Along similar lines, the atheist philosopher David Benatar proposes that, in the absence of cosmic purpose, life is so meaningless that we are morally required to stop reproducing so that the human race dies out.
I've stopped reproducing. This is because I am poor, very ugly, and fart incessantly. Will Benanart give me a medal?
At the other extreme, it is common for humanists to argue that cosmic purpose would be irrelevant to the meaning of human existence.
Every type of purpose is meaningful for us. This computer wants to fuck me up. That's why I've ordered a new one.
I take a middle way between these two extremes. I think human life can be very meaningful even if there is no cosmic purpose, so long as we engage in meaningful activities, such as kindness, creativity and the pursuit of knowledge.
Farting can be a very meaningful activity. Indeed, on occasion, it is the only humane response to a tedious procedure- e.g. a committee meeting.
But, if there is cosmic purpose, then life is potentially more meaningful. We want our lives to make a difference. If we can contribute, even in some tiny way, to the good purposes of the whole of reality, this is about as big a difference as we can imagine making.
Sadly, what we imagine is irrelevant. It is what other sentient beings think or feel about us which matters.
There are no certain answers to these big questions of meaning and existence. It’s possible the abundant evidence for cosmic purpose in our current theories will not be present in future theories. Even if there is a fundamental drive towards the good, without an omnipotent God, we have no guarantee that cosmic purpose will ultimately overcome the arbitrary suffering of the world.
A lot of arbitrary suffering has been ameliorated by people doing smarter and smarter things.
But it can be rational, to an extent, to hope beyond the evidence.
It is entirely rational to have Faith. Beliefs are another matter.
I don’t know whether human beings will be able to deal with climate change; in fact, a dispassionate assessment of the evidence makes it more likely perhaps that we won’t. Still, it’s rational to live in hope that humans will rise to the challenge, and to find meaning and motivation in that hope. Likewise, I believe it’s rational to live in hope that a better universe is possible.
Rationality is about opportunity cost. Having Faith, like feeling Happy, doesn't have an opportunity cost and is beneficial. Living in the hope that x happens has the opportunity cost of not hoping for some y. It is rational to minimize opportunity cost. Have Hope, Faith, Love, and Joy by all means. But why bother to stipulate for some x rather than some y as being your raison d'etre?
In economics, one consequence of 'Knightian Uncertainty' is that it is 'regret minimizing' to have ontologically dysphoric goods and services- some of a positional type. Why should an epistemological principle of 'economia' as opposed to 'akreibia', not arise in the natural sciences- at least as interpreted by philosophers and theologians?
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