Luke Barnes' Fine Tuning Argument

Luke Barnes complained (rudely) that I did not deal with his actual argument in Terms and Conditions – A Fine-Tuned Critique of Ikeda and Jefferys (Part 1). So let's look at it.

I skimmed over Barnes' restatement of Ikeda & Jeffries argument. I didn't see anything new from the original. I'll skip to Barnes' own argument.

I'll briefly restate his variable definitions, without his digressions on evolution. One problem that Barnes' has in his argument is that he's not crystal clear in his definitions of random variables. Barnes uses the terminology "this universe" without being super-explicit that this universe was randomly selected. There are only two serious problems in his definitions, which I'll get to in a minute.

1. $L$: A randomly selected universe contains life
2. $X$: The physics of a randomly selected universe is sufficient for the existence of life
3. $I$: The causes of the physics of a randomly selected universe were indifferent to whether those physics were sufficient for the existence of life. The complement, $I^C$ (Barnes' $\ov I$, which doesn't render well), is that the causes of the physics of a randomly selected intentionally created life.

The problems come in Barnes' definitions of $N$ and $F$. Barnes defines $N$ as "the natural phenomena of this universe are the causal products of the physics of this universe." It is unclear whether or not this is a random variable. However, Barnes conditions everything on $N$. Therefore, if $N$ is not a random variable, it is just a truth of all universes; if $N$ is a random variable, we can just take our sample space to be $N$.

Note that Barnes correctly states that $P(X|LN)=1$; since we're looking only at the sample space where $N$ is 1, the equivalent is $P(X|L)=1$.

The second, somewhat more serious problem, is his definition of $F$: "in the set of possible physics, the subset that permit the existence (evolution) of life is very small. In other words, the physics of a particular universe must be fine-tuned if that universe is to support the existence (evolution) of life." This does not look at all like a random variable. Instead, it looks like a scalar probability: $f=P(X|I)$. As a scalar, both advocates and critics of the FTA stipulate (arguendo) that $f<<1$. I don't think these quibbles seriously affect his argument, but clearing them up simplifies everything considerably.

(However, Barnes does assert that "IJ’s 'N' slightly misses the point. The question is whether physics is fine-tuned and what we can conclude from this, not whether there are any exceptions to the laws of nature." This is an overstatement. Ikeda and Jeffries might miss Barnes' point, but I think they directly tackle points made by others, especially the non-empty set of theists who assert the possibility of "miracles.")

I think I can skip over Barnes' restatement of Ikeda and Jeffries, and just accept that Barnes is making a different argument from the one that Ikeda and Jeffries make.

Barnes then wants to investigate the ratio:
$$R≡{P(I|LXFN)}/{P(I^C|LXFN)}$$
Given that Barnes $F$ does not seem like a random variable and $N$ defines our sample space, we can simplify:
$$R≡{P(I|LX)}/{P(I^C|LX)}$$
But by Ikeda and Jeffries' extension to Bayes theorem:
$$P(I|LX)={P(X|IL)P(I|L)}/{P(X|L)}=P(I|L) \text " given that " P(X|L)=1$$
$$P(I^C|LX)={P(X|I^CL)P(I^C|L)}/{P(X|L)}=P(I^C|L)$$
By Bayes Theorem again,
$$P(I|L)={P(L|I)P(I)}/{P(L)} \text " and " P(I^C|L)={P(I^C|L)P(I^C)}/{P(L)}$$
Therefore (simplifying):
$$R={P(L|I)P(I)}/{P(L|I^C)P(I^C)}$$
Given that we stipulate $P(L|I^C)=1$,
$$R=P(L|I){P(I)}/{P(I^C)}$$
Again, even if we we stipulate $P(L|I)<P(X|I)<<1$, then $R<1$ iff $P(L|I)<{P(I^C)}/{P(I)}$, which is the point I made in my previous post.

Let's look again at his original argument. Barnes' does fine until he reaches his first problem between iii) and iv):
$$\text "iii) " P(L|IFN)<<P(L|I^CFN) \text " thus, iv) " {P(I|LXFN)}/{P(I^C|LXFN}<<{P(I|N)}/{P(I^C|N)}$$
This conclusion is more or less true, but it is poorly stated. As I noted in my previous post, it is already admitted that $P(I^C|X)>P(I^C)$ and $P(I|X)<P(I)$, regardless of the magnitude of $f=P(X|I)$, so long as $f<1$, and the smaller $f$ is, the more it "swings" the relative probabilities. However, Barnes' use of << in iv) is unwarranted; without knowing the magnitude of ${P(I)}/{P(I^C)}$, we don't know know if ${P(I|LXFN)}/{P(I^C|LXFN}$ is a lot less than ${P(I)}/{P(I^C)}$. But it is less than, again which is already admitted.

Essentially, as I wrote in my previous post, Barnes post is just an overcomplicated version of this post; he's added nothing new.

Even more on Fine Tuning

The central portion of the Fine Tuning Argument (FTA) is valid: Assuming that $P(L|C)=1$ by definition, then $P(C|L)={P(L|C)P(C)}/{P(L)}≥P(C)$. Assuming that $0<P(C)<1$ and $P(L)<1$ then $P(C|L)>P(C)$. Observing that life exists definitely raises the ex ante probability that a creator exists for this world. Life is, in a sense, "evidence for" a creator.

However, to accept this argument as meaningful, we have to assume that $P(C)<1$. This assumption seems to require that we bite a serious philosophical bullet. If we take a frequentist ontology, then $P(C)<1$ means that there exist possible worlds where no creator exists. This contradicts one theistic definition of God as a modally necessary being: if God exists, God exists in all possible worlds. In this case, $P(C)=1$, and $P(C|L)=1$; because we were already certain, by definition, that God existed. Under a Bayesian ontology, $P(C)$ represents our subjective confidence that God exists, and $P(C)<1$ entails that we can reasonably be in doubt that God exists, which contradicts at least Plantinga's argument that God as properly basic: $C⇒P(C)=1$. Thus, if the FTA is rationally persuasive, then God must be neither modally necessary nor properly basic. But suppose we bite these philosophical bullets.

Another portion of the FTA is also valid: Assuming that $P(L|~C)<P(L)$, then $P(~C|L)={P(L|~C)P(~C)}/{P(L)}<P(~C)$: Observing that life exists definitely lowers the ex ante probability that no creator exists for this world.

But so what? We really want to know whether or not $P(C)>P(~C)$. The question is not whether observing life makes the race closer, we want to know if observing life changes the winner. We want to know if $P(C|L)>P(~C|L)$. Because we want to know if this particular inequality is true that we must condition on $L$. The FTA does not, however, help us answer this question. Regardless of how small $P(L|~C)$ is, we do not know whether or not it is less than $P(C)$, and the FTA requires that $P(C)>P(L|~C)$. If we simply assume that $P(C)>P(L|~C)$, then we can just as simply assume that $P(C)<P(L|~C)$ (neither assumption entails a contradiction), so the FTA works only on an arbitrary choice of assumptions, which essentially begs the question. And, according to Ikeda and Jeffries, we have a plausible argument that $P(C|L&F)<P(C|L)$, because $P(~F|C&L)>0$. If we assume that $P(F|C)=1$, then $P(F|C)=P(L|C)$ and we're back where we started.

More on Fine Tuning

Luke Barnes has asked me to look at Part 1 of his defense of Fine Tuning against Ikeda and Jeffries' critique. Part 1 is, unfortunately, over-complicated, and, as best I can tell, the complications obscure rather than explain the underlying point.

We can concede the most basic Fine Tuning argument: The existence of life does indeed raise the probability that a life-designer exists and designed life. At a very basic (not fundamental) level, the existence of life is indeed evidence for a life-designer. This conclusion has absolutely nothing to do, however, with Fine Tuning. Even if we were to conclude that all logically possible physics guaranteed the existence of life, then it would still be the case that the existence of life was evidence for a life designer (or a life-friendly-physics designer). I don't even need to get into complicated probability math. We can simply look at the alternative: if no life existed, then that would absolutely falsify the existence of a life-designer, in just the same sense that the fact that we observe that no hoverboards exists absolutely falsifies the existence of someone who has (successfully) designed a hoverboard.

The problem with defining evidence in this sense is that it's far too broad. I used to play poker. Sometimes I would win, sometimes I would lose. Just the fact that I lost on some particular day is evidence in the above sense that someone was cheating that day. Again, in a similar sense, had I won that day, I would have known with certainty that no one was cheating.* Possibly cheating is greater than definitely not cheating. Similarly, the fact that each star in each galaxy is arranged in the particular positions we observe is evidence that it was done intentionally: had we observed a different arrangement, that would definitely falsify the hypothesis that they were deliberately arranged in the positions we do observe.

*Or if they were cheating, they were cheating to lose, against which I have no objection.

However, the fact that I lost some days and won some days, and that all the stars in all the galaxies are in the positions that we observe are also evidence for the fact that these events happened by chance. Again, observing something different would falsify the hypothesis that the specific event occurred by chance. If a specific event had not happened, then the hypothesis that the event actually happened by chance would be certainly false.

So observing the existence of life is evidence for the hypothesis that life was created, and it's also evidence for the hypothesis that life happened by chance. Wait, what? How can something be evidence for contradictory hypotheses?! Well, the hypotheses are not contradictory. They're mutually exclusive, but neither "life was designed" nor "life exists by chance" is the complement of the other. Logical consistency demands only that evidence for some hypothesis must be evidence against its complement , not against some other event that is merely mutually exclusive.

Thus, that life exists proves that the complement of the union ("life was designed" or "life happened by chance") is definitely false, which implicitly proves that both "life was designed" and "life happened by chance" have a higher ex post probability than they had ex ante. However, we still have to distinguish between the two probabilities. Hence we start doing things like conditioning on the existence of life, and we get Ikeda and Jeffries.

Fine tuning and probability

Luke Barnes criticizes this version of Ikeda and Jefferys' paper, "The Anthropic Principle Does Not Support Supernaturalism." (I usually link to this version; I assume the content is identical.) Barnes' post is five years old, but it's still be referenced by some people, so I guess it's still alive enough to be worth rebutting. In his criticism, Barnes runs afoul of some of probability's conceptual problems.

In general, probability is very philosophically problematic. Definitely with the frequentist interpretation, but also with the Bayesian interpretation, using probability requires us to adopt an ontological commitment to the existence of unknowable things: frequentism requires us to talk about experiments not performed, Bayesianism requires us to talk precisely about what we don't know. It is philosophically respectable to reject probability entirely: the past is fixed and certain, the future is determined by the present, and it is incoherent to measure our ignorance. However, if you're going to use probability to make inferences, you have to bite all the philosophical bullets that probability requires.

To briefly recap, the Fine Tuning Argument (FTA) says that, given relatively unproblematic assumptions about the laws of physics at the most general level, the probability is very low that the (apparently) arbitrary constants of the laws of physics, i.e. those constants whose values cannot be determined theoretically and must be determined observationally, are such that life can exist. We human beings apparently got ridiculously lucky when the universe formed almost perfectly set up for life to evolve. The Weak Anthropic Principle (WAP) rebuts the FTA: if the universe were not "fine tuned" for life, we would not be around to observe otherwise; of course we observe that the universe is "fine tuned." Barnes counter-argues that if we are required to condition on the result (life exists), then probabilistic arguments are generally useless. Barnes is correct: if we are required in principle to condition a probabilistic argument on the result, then probabilistic arguments are useless. However, he is not correct that Ikeda and Jeffries argue that we are required in principle to condition on the result.

We have to make additional assumptions to make probability work. First, we have to be conceptually able to "observe" both success or failures. If we cannot in principle observe failures, then we cannot make any inference at all about the probability of the successes we observe. This is a trick that "psychics" use: they show the hits but hide the misses. Second, we have to be conceptually able to describe success before we actually observe it. In a large probability space, every actual event has a very low probability. Shuffle a deck of cards and then look at it: before you shuffled it, the probability that the deck would end up in exactly that order is $1/{52!}≈1.24×10^{-68}$.

The difference between the FTA and Barnes' example is that in the FTA, we cannot in principle, even conceptually, observe a universe that does not have life in it. In contrast, I personally could in principle have observed Magneto and his grandson being killed by the shrapnel. Furthermore, even though the grandson could not have actually observed that outcome, he could conceptually have "observed" the alternative outcome, e.g. by observing that other people actually died.

Ikeda and Jeffries invert the FTA. Instead of asking the probability of naturalism, they ask the probability of God existing. We first assume first that if God does not exist, then life will exist only in a life-friendly universe. Life existing entails life friendliness $P(F|~G&L)=1$. We don't have to condition on L, but if we do, then if $G$ is false then $F$ must be true.

We then consider two alternative hypotheses. The first hypothesis is that if God₁ exists, then He would have created a life-friendly universe, If that is the hypothesized God, then observing life-friendly universe with life in it (our only actual observation) does not distinguish between the existence and non-existence of God. The second hypothesis is that if God₂ exists, then He would have created life, and might have created life in a non-life-friendly universe. In this case, Ikeda and Jeffries correctly argue that observing life in a life-friendly universe lowers (slightly) the probability that God₂ exists (in the same sense that observing a non-black non-crow raises the probability slightly that all crows are black).

We don't have to condition on life existing. However, we're worse off. We could not conceptually have predicted before observing any universe that life would exist in it. The only reason we have to assume that if God exists, He would have created life is just that we are in fact alive. We are "predicting" the random order of the deck after we've seen it. (Positing indirect attributes of God that entail His creating life just move the problem around.) Just the hypothesis that if God exists, he would have created anything we actually see begs the question: it assumes what we are setting out to "prove." Plantinga would call that an adequate argument, but Plantinga is a doofus who doesn't understand modal logic or probability.

In short, the Fine Tuning Argument for the existence of God is dead. It either provides evidence against the existence of God, or it fails to satisfy the requirements to even make a probabilistic argument in the first place.

Social constructions and Libertarianism

Social constructions are socially and subjectively created facts: a social construction labels some entity that exists only in the minds of (most) people in society. The most obvious example of a social construction is an agreement between two people. The agreement itself does not name any entity in the external, objective world (the physical world that does not include our minds); it names just the fact that some particular mental state is shared between the two people.

There's nothing weird or objectionable about social constructs; we've been creating social constructs since we began speaking. Indeed the primary function of speech is to create social constructs; although of undeniable importance, the utility of speech for communicating information about the external world is only secondary.

Ownership, as distinct from possession, is a social construct. Ownership might reference possession, but ownership and possession are different concepts. Possession is a physical fact; ownership is a shared idea, an idea in the minds of individual members of a society. Even were we to all agree that possession, and only possession, entails ownership, possession would label the physical fact of having some object in a person's physical control, an external fact; ownership would label the ideas in our minds that physical possession was legitimate.

Libertarianism (with absentee ownership) defines a specific social construction of ownership, one that does not correspond to possession. As best I can figure out, Libertarianism establishes ownership as only the unbroken chain of voluntary transfer of property from the original creator to the current owner, and the near-absolute power of the owners of property to use, not use, or destroy that property as they please.

In contrast, non-Libertarian philosophies construct ownership as in some way departing from either or both of the transfer principle or the absolute use principle. Liberal capitalism, for example, permits taxation (i.e. the government may legitimately compel the transfer of some property). Communism, as another example, forbids the private ownership of the means of production; the means of production may no more be privately owned than a human being.

It's more difficult to decide between social constructions than external referents. Both are, in a sense, socially created (e.g. we have simply agreed that the word "mass" refers to an object's tendency to resist acceleration), but a social construction does not refer to anything in the external world, and we cannot distinguish between conflicting social constructions directly on a scientific basis.

Hence the oft-repeated question: why should we prefer to legitimatize the Libertarian social construction of ownership to alternative social constructions of ownership? It cannot be that the Libertarian construction is scientifically determinable, because "ownership comes from the unbroken voluntary transfer from the original creator" does not directly reference anything in the external world, the world we can — if we are to believe the scientists — made decisions about using the evidence of our senses.

We can, of course, always appeal to pragmatism, an indirect scientific justification. We can say that legitimatizing this or that social construction will have specific external, scientifically determinable results, results we find clearly more or less preferable than other results.

The big problem with Libertarianism is that the deontic and the consequentialist justifications for Libertarianism both seem weak. Since Libertarianism is a social construct, not directly scientifically justifiable, I can't see any way to justify Libertarianism deontically by anything but argument by vehement assertion. And the pragmatic justification seems to rely on at best naive optimism and at worst a willful ignorance of facts. (The most administratively efficient* health care systems in the United States, for example, are Medicare/Medicaid and the Veterans Administration.) When the weaknesses in the pragmatic justification become apparent, Libertarians almost always seem to switch instantly to the deontic justification: whether or not it works "better" than current systems, the Libertarian version is intrinsically better because people will have more "choice." Of course, it would be great if any ideology were both deontically and consequentially preferable, but they seem to try to use each justification to shore up weaknesses in the other justification.

The switch between the deontic and pragmatic justification to shore up (and at worst distract) weaknesses in the other justification is most reminiscent of Christian Apologists. (While religious apologists hold no monopoly on fundamental defects of justification, they are the most vigorous and numerous examples.)

To a skeptic, if an argument is good enough to use to support a proposition, then its failure contradicts the proposition, or at least calls the truth of that proposition into serious question. If I believe something because of an argument, then if the argument fails the belief should fail too. If I believe something not because of some particular argument, then it seems dishonest to use that argument to support the belief.

For example, I believe that communism is better than capitalism because I believe the social ownership of the means of production would lead to more happiness and satisfaction in the world. I justify my communism on purely pragmatic grounds. If someone shows me that communism, or some aspect thereof, would lead to a worse outcome, then I will change my conception. For example, we know from experience that while it might be effective at quickly industrializing a poorly-industrialized country, unconstrained political rule by a self-selecting party elite has serious negative consequences when industrialization reaches a certain stage. I therefore abandon the idea of such a party elite. If the theory does not fit the facts, the theory must change.

An apologist, on the other hand, in some sense "just believes." The arguments and reasons proffered really have nothing to do with the foundation of the apologist's beliefs; the arguments are tools only of persuasion, not justification. Either the belief is mystical, revelatory, or the actual foundations of belief are at best subconscious and at worst intentionally covert.

Hence, to a certain extent, arguing with apologists is an exercise in futility. A rebuttal has no effect; they do no believe because of the argument, so even a decisive rebuttal does not undermine the belief. Furthermore, even showing that the argumentation is disingenuous in this sense is such a subtle point that only someone with considerable education, training, and experience in critical thinking and rational belief formation can spot the disingenuity, and those people are already strongly predisposed against mystical or covert belief.

Really, the only value in taking to apologists, religious, political, or ideological, is to try to gain insight into good questions to ask; even though their answers are defective, the questions are almost always valuable. Indeed, a good question is a thousand times better than a good answer. (Happily, there are a thousand times as many good answers as their are good questions.)

The argument from morality

The general theistic philosophical argument from morality* essentially states that without a god, there are no objective (or absolute) moral standards; without objective moral standards, we have no basis to call anything good or bad. There are three important rebuttals to this argument.

*The separate evidentiary argument states that it is impossible to offer a good naturalistic account for observed human moral behavior.

I. Even if there were no god, there might still be objective moral standards. There are, of course, objective physical truths that naturalists can account for without a god; perhaps the same might be true of moral standards. Many non-theistic philosophers (and some theistic ones) have offered natural accounts for objective moral standards, notably moral realism. I think these arguments fail, but they fail on epistemic grounds; there is nothing ontologically outrageous about moral realism.

II. Theism does not offer objective moral standards. In the sense of "objective" as "not a property of a mind", theistic morality is established by the mind of god, and ipso facto subjective. In the sense of "objective" as "rationally determinable" (in the sense that it is objectively true, i.e. rationally determinable, that "2+2=4" is a theorem of arithmetic), theism offers no rational epistemic method to determine properties of the mind of god.

III. Even without objective moral standards, we still have a basis for calling things good and bad: our subjective preferences. Of course, a subjective account of morality fails to offer a basis for calling some moral beliefs mistaken or false, but there's no particular reason to require that the good be the true. It's not false or contradictory to say that I disapprove of slavery, and I disapprove so strongly that I'm willing to employ coercion to eradicate, prevent or punish it. If you believe just as strongly that slavery ought to be tolerated, we'll just have to fight it out. An examination of human history — notably the American Civil War — shows that this is actually how many moral arguments have been settled.

That we can and have settled some moral arguments just by talking about them does not entail that there is some objective truth to moral questions. Moral discourse is substantively different from scientific discourse: science relies on falsifiability and evidence; moral discourse relies on compromise, negotiation and propaganda (in the broadest sense of trying directly to change others' subjective preferences). We've developed preferences at an abstract level: We prefer to compromise some of our concrete moral preferences rather than fight about every moral question.

The contradiction in the argument that we would prefer to have an objectivist account of morality and therefore there actually is an objective account of morality should be obvious.