(In which I make fairly uncontroversial points about evidence using controversial examples, thus providing my own red herring.)
There is a logical fallacy known as appealing to authority, which goes like this.
1. X believes Y
2. X is very clever / a well known expert / a professor / a reliable person …
3. Thus, Y is true
This is a fallacy because people can be wrong, even smart people.
However, we all believe things because someone told us so. We would make impossibly slow progress in life if we had to verify every belief for ourselves. There are people we usually trust – not blindly but because they’ve proven trustworthy.
Modern science has a rather strained relationship with authority. On the one hand, much of science’s early progress came from following the maxim: “don’t believe everything Aristotle said”. If you want to know what the natural world is like, go ask the natural world. Go into the lab, go get a telescope, go find out for yourself. Experiments shouldn’t just be repeatable. They should be repeated.
On the other hand, science has made so much progress, collected so much data, published so many papers that no one person can have checked it all out for themselves. The astronomy preprint archive posts about 100 new astronomy papers per day. We are reliant on the honesty and competence of other scientists who provide us with measurements, constants, equations, simulations. We can check some of it but not all.
The layman is in an even worse position, as they may not have the training, time and skills to verify the conclusions of science even if they wanted to. Should Jo(e) Public believe that the universe is expanding because scientists say so? Or should they build their own telescope, invent the spectrometer, locate and observe distant galaxies, measure atomic emission spectra, calculate the recession velocities of the galaxies, observe Cepheid variable stars, discover their period-magnitude relation, use this relation to measure the distance to galaxies, note the linear dependence of velocity on distance, discover general relativity, solve for an expanding spacetime, derive the linear dependence of velocity on distance, and then (and only then) conclude that the universe is expanding?
The truth, of course, is somewhere in the middle: Jo(e) public can understand how scientists have reached the conclusion that the universe is expanding, so that this central pillar of the Big Bang theory is not pure assertion. They can follow our path on a map, as it were, even if they do not tread every step again themselves. Science ultimately appeals to observations of the natural world, even if they are usually someone else’s observations.
So when should we believe an authority? When does quoting an authority commit the aforementioned fallacy? The key is to be specific about what is being claimed.
Authority as evidence
We mustn’t confuse knowledge with certainty. We need to reason using probabilities. Bayes theorem teaches us how to update our probabilities when new, relevant information comes to light. Learning that a particular expert believes something is new, relevant information. It may not be decisive, but shouldn’t be ignored.
1′. X believes Y
2′. X is in a position to assess the evidence for and against Y. X is informed, competent, experienced, has a reputation for honesty, has no conflict of interest etc.
3′. Thus, the probability of Y being true has increased.
A belief is justified or warranted if it was formed using reliable methods, which can be counted on to produce true beliefs most of the time. Recognising those methods in another person adds weight to their opinion.
Authority as establishing the burden of proof
I really shouldn’t choose such a hot-button topic to make a point like this, but it’s such a good example that I can’t resist. Take climate change. The majority of the climate science community has concluded that the evidence supports the hypothesis that human activity has and will lead to substantial, detrimental changes to our planet’s climate.
Does that prove that climate change is real? No. Proving is something that mathematicians do. It does, however, set the standard for those who believe that climate change is not real. The scientific consensus is prima facie evidence of the truth of climate change. Jo(e) Public is justified, in the absence of the time and skills to investigate for themselves, in believing that climate change is more likely to be true than false. Those who wish to believe that climate change is probably not real have the burden of showing that the scientists are wrong.
This is an application of my last point – authority as evidence. The consensus of an expert, informed community tips the scales in favour of climate change. The pronouncements of scientists are not infallible, but should not be rejected without good scientific reasons. Political conservativism, conspiracy theories and a desire to be viewed as an “iconoclast” are not good reasons.
Authority and Relevance
A key idea in the previous section was relevance. When an climate scientist reaches a conclusion about the state of the Earth’s climate, he is commenting on exactly the thing that s/he studies. There is a danger of experts being viewed as generically clever and thus authorities in any field they care to address. As usual, xkcd summarises the point beautifully.
Another controversial example. I once saw someone on TV (possibly a news vox pop), when asked about life after death, cite as conclusive evidence the fact that Stephen Hawking doesn’t believe that there is life after death. Now, I have every respect for the prodigious talents of Professor Hawking, a scientist above whom the superlative “greatest” justifiably hovers. But none of the things that Hawking has done to gain his reputation have anything to do with life after death. He is an expert on quantum gravity, black holes, general relativity, and the cosmology of the very early universe.
Is there any evidence for life after death? Near death experiences, religious revelation, philosophical (metaphysical) arguments for the immateriality of the soul, and widespread belief in life after death around the world and throughout history are the factors usually cited. So the relevant areas of expertise are medicine, especially neuroscience, as well as a familiarity with the claims of witnesses, the psychology of human beings (e.g. fear of death), philosophy, comparative religion, etc. Life after death is usually taken to be incompatible with philosophical materialism, so philosophical arguments for materialism are also relevant. Prof. Hawking is not an expert in any of these areas. There are, I assume, plenty of doctors, neuroscientists, psychologists and philosophers with the relevant expertise who discount near death experiences and the afterlife. If you want to cite an authority, cite them. Hawking’s opinion in this area is worthy of consideration, of course, but not authoritative.
Beware of 8 out of 10 Authorities
The previous point applies a fortiori to surveys of experts. For example, the fact that a larger-than-average percentage of scientists do not believe in God would seem to explain itself. But there is a possible selection effect. It’s the same selection effect that one may suspect is behind the fact that, while (roughly) 80% of philosophers are atheists, this drops to just 20% of those philosophers who specialise in philosophy of religion.
It’s the same old correlation vs. causation story. Did a random sample enter both fields, and thereafter have their views moulded by their respective subject matter? Or did a prior belief in God lead some to be philosophers of religion, while a lack of belief led others to become scientists? A survey of 1,646 scientists by Rice University sociologist Elaine Howard Ecklund led her to conclude that (from here):
Ecklund concludes from her research that most scientists do not become irreligious as a consequence of their becoming scientists. “Rather, their reasons for unbelief mirror the circumstances in which other Americans find themselves: they were not raised in a religious home; they have had bad experiences with religion; they disapprove of God or see God as too changeable.” The disproportionately high percentage of nonbelievers among scientists (as compared to the general population) would appear to be the result of self-selection: the irreligious seem more likely to become scientists in the first place.
I’m not a sociologist, so I can’t critique Ecklund’s work. The point is that individual biases don’t necessarily average themselves out over a population of experts, so appealing to lots of authorities isn’t necessarily an improvement.
Authority as a counterexample to the accusation of ignorance
The defender of the Kalam cosmological argument for the existence of God claims that the universe has a beginning. One argument goes as follows:
Premise 1. An actual infinite cannot exist in reality.
Premise 2. An infinite temporal regress of events is an actual infinite.
Premise 3. Therefore, an infinite temporal regress of events cannot exist.
Reasoning with actual infinites requires knowledge of mathematics, specifically transfinite arithmetic. The argument’s best known defender is William Lane Craig.Craig is not a mathematician, and so one might wonder whether he is sufficiently familiar with the relevant mathematics. We all know of arguments that reveal more about the ignorance of the arguer than about the subject at hand.
There are two ways for Craig to counter the accusation that a greater knowledge of mathematics would lead one to reject Premise 1. The long way is to demonstrate his own proficiency in transfinite arithmetic. That would take a while. He discusses the topic at length in his book “The Kalam Cosmological Argument” if you want to take that route. There is a shortcut, however. Craig could provide an example of someone whose mathematical credentials are unquestioned and who affirms Premise 1. Craig can do this, and so usually does so in shortened presentations like debates. The authority is David Hilbert, who was one of the greatest mathematicians of the 20th century and who argued that “the actual infinite is nowhere to be found in reality”.
This is a valid appeal to authority, so long as we are clear on what is being claimed. Obviously, we cannot claim that Premise 1 is true because Hilbert thought so. But we can counter the accusation that anyone who believes Premise 1 is ignorant of mathematics and doesn’t understand the idea of infinity.
(Note well: I’m not defending premise 1. I’m planning a series on the cosmological arguments, so stay tuned. I’m not convinced by “Hilbert’s hotel is metaphysically absurd” style arguments. And, as Jeff Shallit has pointed out, mathematical knowledge of transfinite arithmetic is a necessary but not sufficient qualification as we are dealing with the applicability of mathematics to reality, which is physics. The accusation that “greater knowledge of physics / cosmology / relativity would lead one to reject Premise 1” can also be countered: George Ellis. The main utility of these authorities, I contend, is to take our attention away from the claimers and focus attention on the claims. We won’t get stuck in a useless debate about whether Craig really understands maths.).
Authority and hostile witnesses
A particularly useful form of appealing to authority is the use of a hostile witness. In this context, a hostile witness is one who attests to a fact in the teeth of their own biases. If someone who hates the defendant’s guts nevertheless corroborates his alibi, then this has greater weight as evidence than such corroboration from a friend of the defendant. It works in reverse as well: if the defendant’s loving wife testifies that he was out of the house between 10pm and 1am, knowing that this was the time of the murder, then this is weighty evidence. She has every reason to give him an alibi, and so the most likely reason for her statement is that it is true.
This is one of the reasons that the study of history is not paralyzed by the inevitable bias of those who write history. Is the New Testament useless as a historical record, because its writers were followers of Jesus? Not necessarily, because this bias can be used in our favour. If the gospel writers admit something about Jesus that was an embarrassment to them, then we have good reason to believe that they did not invent this story to suit their own ends.
For example, Mark 13:32 has Jesus saying “But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father”. If we can establish that the early Christians believed that Jesus was divine, then there is a strong bias against inventing a saying of Jesus that says that he didn’t know something. It’s not proof, but it is evidence.
As before, we must be clear about the claim that the authority is supporting. A hostile witness can be used to counter the claim that only those biased in favour of a position believe its claims. I’ve come across this in the context of the fine-tuning of the universe for intelligent life. This subject is so popular with theists that I often encounter the claim that it is the product of Christian apologetics, and believed only by “religious types”. Actually, much has been written on fine-tuning in peer-reviewed scientific journals and I can (and have) give many examples of non-theist physicists who affirm that life-permitting universes are rare in the set of possible universes.
But don’t take my word for it …
I can (and have) give many examples of non-theist physicists who affirm that life-permitting universes are rare in the set of possible universes.
Except that you and the other physicists literally have no idea what the entire set of possible universes is. You, and the others, reason on the basis of the one particular universe we see, assuming that any universe must be built in approximately the same way, ignoring the vast number of other possibilities. For example, I asked before, where is Conway’s Life model (certainly a possible universe) represented in your probability distributions?
What I find interesting about Conway’s Game of Life is this, from Wikipedia: “Conway chose his rules carefully, after considerable experimentation”. This throws serious doubt on the claim (made a couple of paragraphs earlier on Wikipedia) that “The game can also serve as a didactic analogy, used to convey the somewhat counter-intuitive notion that “design” and “organization” can spontaneously emerge in the absence of a designer”.
You’ve raised this objection twice before and I’ve answered it twice. You haven’t replied either time. So here we go again. (https://letterstonature.wordpress.com/2012/05/02/in-defence-of-the-fine-tuning-of-the-universe-for-intelligent-life/ and https://letterstonature.wordpress.com/2010/04/11/what-chances-me-a-fine-tuned-critique-of-victor-stenger-part-1/, incidentally.)
A “universe” is possible if it is self-consistent. So it’s not just a matter of declaring that a universe is possible. We investigate its mathematical description to see if it is free from contradiction. In most cases, the case for logical consistency is as strong as one could possibly hope for – the equations in question are known to describe our universe, and only differ in the constants we plug into them. The mathematical consistency of the equations is not dependent on the value of these constants (within limits – for example, a particle with mass larger than the Planck is probably not possible, since our concept of mass simply doesn’t make sense in such a regime). The same is true for initial conditions – the laws of nature describe a set of solutions, subject to the same laws but with different boundary conditions. (E.g. the set of orbits around the sun consistent with Newtonian gravity). Thus, the laws of nature carry with them a set of physically possible universes in their parameters and solutions. They represent the best scientific information we have on what if physically possible.
As a concrete example, consider the equations that describe the cosmic microwave background (CMB). These equations contain a term describing the density of baryonic (a.k.a. ordinary) matter, Om_b. We can solve the equations for a range of values of Om_b, as shown here: http://ned.ipac.caltech.edu/level5/March10/Garrett/Figures/figure3.jpg . One of these lines, at most, represents the actual universe. What are the other lines? The most straightforward interpretation is that they represent conditions in universes other than ours, universes which are possible but not this universe. If we want to know which one describes our universe, we have to go and measure CMB. There isn’t the slightest trace of logically consistency helping us out.
Perhaps you think that a universe could turn out not to be possible for some other reason, other than logical consistency, Well, what? If that other reason is another, deeper physical law, then fine-tuning asks what properties that law needs to have in order for a universe described by that law to be life-permitting. A good example is string theory. Even if string theory contains no free parameters, there are a huge number of solutions characterised by hundreds of parameters. The metalaw exchanges constants for initial conditions. We still have a parameter space to explore and a life-permitting range to identify.
so the most likely reason for her statement is that it is true.
No, this does not follow. One could reasonably argue that the most likely reason for her statement is that she believes that is true, but that is an entirely different matter.
I think a reasonable case could be made from inferring from her bias for her husband and her belief that he was out of the house to the truth of her belief. The most likely cause of the belief is the truth of the belief, given her bias against inventing the belief.
Some of the points you make here, Luke are very good. But I think you have over looked a few others.
The argument from authority might be valid not because a respectable authority holds a certain opinion, but do the vast majority of authorities hold a certain opinion. Also are those opinions based upon sound evidence or something else?
There are respectable medical scientists that think HIV does not cause AIDS, Kary Mullis has a Nobel Prize in medicine and argues this. Yet I doubt the vast majority of researchers agree with him. If so his authority isn’t worth much.
Let us suppose a consensus existed in astronomy that quark stars exist or that life exists outside of the Earth. I suspect the latter is the case. We may ask what evidence would there be for such a consensus, if the authorities admit none, this can’t be treated in the same way that neutron stars exist. Most of us can’t check the existence of neutron stars but we can ask the authorities how do they know they exist? They will say they’ve observed them and then the layman have to ask how likely is it these observations are wrong and still got past the whole community. Not very likely I think..
David Hilbert was certainly one the great mathematicians of his day, but his day was a hundred years. Ago. Perhaps the field has moved on. What is the consensus of mathematicians now? is the important question; not what did one mathematician say a hundred years ago.
Craig’s use of authority quotes is slippery and misleading in the extreme. In particular he will quote an authorities opinion when a consensus does not exist and then pass it off as consensus. Alex Vilnekin thinks the universe must had a beginning and came from “nothing”. But plenty of other authorities such as Roger Penrose, Sean Carroll, Anthony Aguirre, Abhay Ashtead, Paul Frampton, etc disagree. They are not less qualified than Vilenkin. There a genuine disagreement amongst authorities on this question. So to quote one whose arguments suit you is extremely misleading. Perhaps that needs a mention when discussing Craig and arguments from authority.
The problem of rogue authorities is a tricky one. Perhaps the most you can prove from the existence of scientists like Kary Mullis is that the case for AIDS denialism lies somewhere between “ridiculous and dismissible” and “a genuine competitor to the paradigm”. Enjoy placing your favourite theory on that continuum.
Mathematical theorems don’t go out of date. Hilbert’s comments came in a 1926 article “Über das Unendliche”. Cantor died in 1918, and by then the basics of transfinite arithmetic were in place. The mathematical results relevant to the Kalam argument were well known to Hilbert, so his opinion is still relevant. At the very least, the onus is on the critic of Hilbert to show what relevant mathematical results invalidate his opinion.
Certainly, I’m not advocating every authority that Craig has quoted. Craig and Sinclair’s article in the Blackwell Companion to Natural Theology is his most complete engagement with the cosmological literature. As Sinclair says: “If one addresses all the possibilities rigorously, I think one CAN come to a conclusion that our universe has a beginning. Those that seek to refute this conclusion are going to have to grapple with the full rigorous essay and its implications. No shortcuts.” (http://www.reasonablefaith.org/current-cosmology-and-the-beginning-of-the-universe). I’m planning a closer look at Kalam soon.
“University sociologist Elaine Howard Ecklund led her to conclude that (from here):
Ecklund concludes from her research that most scientists do not become irreligious as a consequence of their becoming scientists. “Rather, their reasons for unbelief mirror the circumstances in which other Americans find themselves: they were not raised in a religious home; they have had bad experiences with religion; they disapprove of God or see God as too changeable.” The disproportionately high percentage of nonbelievers among scientists (as compared to the general population) would appear to be the result of self-selection: the irreligious seem more likely to become scientists in the first place.
I’m not a sociologist, so I can’t critique Ecklund’s work. ”
Sure you can. You don’t need to be a sociologist to see that this is deliberately written to paint atheist physicists as being negative, and only atheists because of some unfortunate event(s) in their lives, whereas the truth is that many physicists (and other scientists) are atheists simply because that is what makes most sense to them. The final conclusion is more than likely true, but the way it is expressed sheds doubts on the author’s motives.
I liked this post until it Christianity and Craig came up. It really makes you look like you’re just pushing an agenda.
I, also liked you post Brendon, until you refused to look at the best explanation of the data due to its conflict with your worldview, looks like your pushing an agenda instead of following the science where it leads.
I don’t see how the problem of rogue authorities is a relevant one if we stick to a good procedure for accepting authority. That procedure is not to accept the authority of any single scientist. But instead to respect the authority for a scientific consensus and even then only if it’s built on something solid like multiple observations. This procedure answers the serious point that you rise that no one can replicate the finding of the millions of papers that are out there. It also answers the problem of the rogue authority. There’s plenty of people who are qualified to talk on a subject but still might bend things for their own ideological/religious/financial/career or even aesthetic reasons.
Hilbert’s comment was not about mathematical theorems; his comment was about what exists in nature. So arguably Hilbert can acclaim no authority here at all. But even if it were just a question of mathematic; it’s a human endeavour and humans can make mistakes which are only noticed later by others or maybe not at all. This is certainly possible in mathematics as it is in any field. That’s why the relevant questions are, not what did one mathematician say a hundred years ago, but what is the consensus of mathematicians today. Also how is that consensus formed? Maybe most mathematicians might happen to simply dislike infinity, rather than they have proved it doesn’t exist in nature. Again we need to know is there a consensus and what is that consensus based upon. These are the questions the layman should ask, not is that person qualified in the field?
I’m glad your not advocating every authority Craig is quoting otherwise we would have to agree the multiverse exists and it came into existence without a cause which is what Alex Vielnkin explicitly states.
The Blackwell piece is a clever piece of propaganda; it’s a trick that’s easy to see through. They claim the universe began to exist; the burden of proof is on them as they are making the claim. But instead of proving this they go over models which potentially avoid a beginning and find some problems with those models. Having found problems with each of those models they then declare the universe began to exist. But not so fast any astute reader should say. You now have to see if there are similar problems with beginning models. If there are; they’ve proved nothing. And of course there are loads of similar problems. Did you watch Steindhart’s recent lecture at Perimeter?
http://pirsa.org/displayFlash.php?id=13030079
He very forcefully points out serious problems with the current cosmology. It’s easy to find problems with cosmological models, really easy, quite frankly. The hard part is proving one model is correct, no one has done that which is why there’s no consensus as to what the big bang really is (other than the start of an expansion, we all agree on that).
As far I’m not concerned we don’t know if the universe began to exist. It is not up to us to prove it didn’t, it’s up to them to prove it did, they have to deal with the problems raised by Steinhardt and others. They have to deal with the problems of believing in singularities with all its infinities, they have to show the beginning still remains in quantum gravity. Can it survive holography? Nomura at Berkley says no http://arxiv.org/pdf/1104.2324.pdf
http://arxiv.org/abs/1205.5550
Is he right? I don’t know, but I doubt Craig and friends haven’t proven him wrong. Again it’s a clever trick to pick out the holes in one idea and ignore the holes in the opposite view. Perhaps Craig’s followers fall for it. Fortunately cosmologists aren’t interested in such clever rhetoric. They are happy to wait until wee get something more definitive from science; so far we are still waiting.
I don’t see how Luke is pushing an agenda. I find him quite balanced to be honest. While people uncomfortable with religion might balk at Luke bringing Christianity with Craig into his talking points (he did say controversial) I do find most of his points reasonable.
And I have to disagree with dougaj4, if that were the case, then every scientist/mathematician would be materialist atheists. But that’s not the case for Francis Collins, Kurt Godel, Werner Heisenberg, Georges Lemaître, Ahmed Zewail, Atta ur Rahman, John Polkinghorne, Freeman Dyson, Arthur Eddington list goes on and on and on.
Zeke – eh?
How does what I said imply that every scientist/mathematician should be a materialist atheist (whatever “materialist” means in this context)? Those that find atheism makes most sense will be atheists; those that find it doesn’t will not. In most cases this decision will have been made before they knew an awful lot about science/mathematics, but it hardly seems surprising that people who are attracted to the study of science are more likely to be sceptical about religious belief than average, whereas those who choose to study the relationship of science and religion are more likely to have religious beliefs than average.
When you look at Ecklund’s conclusion, yes she says it’s a selection effect. But where did that conclusion come from? It was her own opinion based on interviews, not from the data. If you look at the data (Table 4 in her book) you see that scientists come from religions homes on the whole (86.6%) . Roughly 90% of the US population believes in god (the figures vary depending on the survey but its roughly around this level). If there were a selection effect you should see a similar level of non belief in elite scientists rather than the average scientist. But in fact elite scientists (members of the National Academy or Royal Society) are less religious. Did Ecklund consider this? No, perhaps because she gets millions of dollars from the religiously motivated Templton Foundation.