Monday, March 27, 2017

Voting for Schmitler

Three people are running for election in Germany: Hitler, Schmitler and Bonhoeffer. Bonhoeffer promises just policies but has no chance of being elected. Hitler promises to kill 50% of minorities. Schmitler promises to kill 80% of minorities. You might think that at this point I will raise the difficult question whether it is permissible, all other things being equal, to vote for Hitler. But I won’t raise exactly that question.

Instead, I want to expand on the above scenario in a different way. Schmitler is incompetent and won’t manage to do more than a quarter of the evils he promises, unlike Hitler who is going to exactly what he promises. So, whom should you vote for? Bonhoeffer who has just policies but won’t be elected? Hitler whose policies are less bad than Schmitler’s, but who will do exactly what he promises? Or Schmitler whose policies are much worse than Hitler’s, but who will do much less bad than Hitler?

There is a good utilitarian case for voting for Schmitler. Here’s an argument for this case. Suppose the elections are occurring in the middle of World War II. It seems that a very reasonable thing for Allied spies to do is to ensure that incompetent people run Nazi Germany. One means to that goal is stuffing ballot boxes with votes for Schmitler. And while typically one shouldn’t stuff ballot boxes, this seems to be a case where the stuffing of ballot boxes would be permissible. So, Allied spies, we suppose, are stuffing ballot boxes in favor of Schmitler. Helga is a German resister to Nazism, working for the Allies. She is an excellent prestidigitator and is going to the voting booth with a sleeve full of Schmitler ballots, in order to stuff the box surreptitiously. If the Allied spies are doing the right thing, Helga is doing the right thing.

Now, if Helga can permissibly stuff the ballot box in favor of Schmitler, then she could permissibly do this: put in a vote for Bonhoeffer (or Hitler), then surreptitiously remove that ballot and replace it with a fake ballot in favor of Schmitler. But if that’s permissible for her, then it would be very strange if she wasn’t permitted simply to vote for Schmitler.

So, it seems, it is permissible to vote for Schmitler on the grounds that he is incompetent, despite the fact that his policies are significantly worse than Hitler’s. But if this is permissible, then it would be a fortiori permissible to vote for Schmitler if he promised to kill 5% of minorities, and this would seem to be permissible even if Schmitler were as competent as Hitler. So, we have an argument that it is permissible to vote for a candidate whose policies represent a lesser evil. Of course, one should never endorse an evil, even a lesser one. So, it follows that voting for a candidate is not endorsement of the candidate’s policies.

I am not wholly convinced by the above argument. I feel a certain pull to the strange view that while it would be permissible for Helga to replace her real Bonhoeffer vote with a Schmitler fake ballot, it would not be permissible for her to vote for Schmitler. After all, strange circumstances make for strange conclusions.

Friday, March 24, 2017

Authorless books

I've been imagining a strange scenario. I come across a text that I know for sure was generated by an entirely random process--say, the proverbial monkeys at the typewriter. I look at it. Mirabile dictu, it's coherent and reads just like a literary masterpiece--let's say it's just like something Tolstoy would have written had he written one more novel at the peak of his creative powers.

I think reading this random text could be a disquieting experience. I could read it shallowly, the way one reads some novels for mere entertainment. And in that context, it would work just as well as shallowly reading a real novel. But of course with a masterpiece, one wants to read it more deeply. In doing so, one draws connections between different parts of the texts ("Oh! So that's what that foreshadowed!" or "Ah, so that's why she did that!"), between the content and the mode of expression ("Look at all these short words describing the rapidity of the march"), between what is overtly the text and other texts, ideas, historical events and persons, etc. Drawing such connections, whether explicitly or just as a barely conscious sensation of something there--is a part of the enjoyment of reading a literary masterpiece, when done in moderation. But in our random text, all connections are merely coincidental. Nothing is there on purpose, not even unconsciously. When we read a literary giant like a Plato or a Tolstoy, when we see a compelling connection, we have good reason to think the author meant it to be there, and that sensing the connection is a part of a good reading of the text. But in the random text, there will be no such thing as a good reading or a misreading. And that would have to be disquieting. There is a sense in which we would be inventing all the connections. Reading would be more like creating than like discovering. I suppose death-of-author people think that's already the case with normal novels. But I don't think so. Real connections differ from chance ones.

At the same time, I think that in practice if I were reading this text which is just like a literary masterpiece, I'd end up suspending my disbelief about the author, and just delight in the connections and subtleties, even if they are merely apparent.

But maybe in a world with God there is no true randomness. So maybe the hypothesis of a book where nothing is intended is impossible?

Wednesday, March 22, 2017

More on life

God is alive, angels are alive, people are alive, dogs are alive, worms are alive and trees are alive. What is it that makes them all be alive, while the Milky Way, the Sun, Etna, a car, a Roomba, and an electron are not? I raised a version of this question recently, and since then have had discussions about it with a number of our graduate students, most extensively with Alli Thornton and Hilary Yancey, to whom I am very grateful.

We could say that they are all alive in an analogical sense. But that doesn’t solve the problem, but simply puts a constraint on the shape of a solution. For to solve the problem, we still have to say something about how this particular analogy works.

Here is the best answer I have right now, but it still has some difficulties I will discuss:

  • A living thing is one that can act in pursuit of its own ends.

This indeed covers God, angels, people, dogs, worms and trees. Moreover, it produces a gradation of life in respect of the degree and quality with which the thing can act in pursuit of its own ends and the degree of ownership the thing has over its ends. For instance, God is omnipotent and perfectly rational, and he is his own end, so he is most fully alive. All the living creatures, on the other hand, have ultimate ends imposed on them by their nature, to the realization of which end their activity are ordered. However, angels and people additionally make a rational choice of ways to realize their ultimate ends, adopting which ways involves setting themselves intermediate ends. Higher non-human animals like dogs do something that approximates this. Moreover, angels, people and dogs have a wide variety of ways of pursuing that end. On the other hand, trees only pursue a limited variety of ends with a limited variety of means.

A bonus of this definition is that we get the conclusion, which seems intuitively correct, that anything that thinks is alive. For thinking is an end-directed activity—it is directed at action and/or truth. So if we ever make an artificial intelligence system that really thinks, it will be alive.

The Milky Way, the Sun, Mount Etna, a car and a Roomba do not pursue their own ends, I think, if only because they are not substances, and only substances own their ends.

But electrons… This is what troubles me. I think that the fundamental constituents of physical reality, be they particles or fields, are substances. And I think all substances have a teleology, and hence have an end. The distinction I would like to be able to make, however, is between activity in pursuit of an end and teleological activity more generally. Electrons in their characteristic activity are acting teleologically. But their action is not in pursuit of an end. Rather their end is simply to engage in this very activity and nothing more. The activity is teleological, but it does not pursue a telos.

But what if it turns out that electrons do genuinely act in pursuit of an end? Then, perhaps, we will have learned that electrons are a very primitive form of life.

What about God, given divine simplicity, though? God = God’s telos = God’s activity. Well, I think that even if God’s activity is identical with God’s telos, one can make a conceptual distinction that allows one to say that God acts for the sake of that telos, a distinction that perhaps is not there in the case of the electron.

As you can see, I am still not very happy with the account. But it’s the best I have right now.

If naturalism is true, there is an infinite afterlife

  1. Deontology is true.
  2. A finite being could not have the kind of dignity that deontology ascribes to human beings.
  3. So, human beings are infinite. (1-2)
  4. If human beings are infinite, they are infinite synchronically or diachronically.
  5. If naturalism is true, human beings are finite synchronically.
  6. If there is no infinite afterlife, human beings are finite diachronically.
  7. So, either naturalism is not true or there is an infinite afterlife. (3-6)
  8. So, if naturalism is true, there is an infinite afterlife. (this is a material conditional following from 7)
Of course, there are also arguments that if naturalism is true, there is no afterlife, and if these are sound, then together we get an argument that naturalism is not true.

Tuesday, March 21, 2017

Eternal life and the crucible of character theodicy

Consider the crucible of character theodicy, that we are permitted by God to meet with great evils in order to form a character with virtues like courage and sacrificial love whose significant exercise requires significant evils.

I take it that it’s clear that forming such a character is worthwhile. But there are at least three problems with this theodicy:

  1. While such character formation is valuable, is it valuable enough to justify our suffering great evils? Wouldn’t it have been better if God just gave us the virtues directly, rather than having us pay a great price?

  2. Even if it is valuable enough to justify our suffering great evils, wouldn’t it be better if we suffered fewer or lesser ones?

  3. What about those who suffer and develop a vicious character?

I think these three problems can be overcome if we think about heavenly life as an infinite value multiplier.

Ad 1: There is clearly some additional value to having virtues that were formed through significantly free exercises of them rather than having had these virtues imposed on one. In heaven, on infinitely many days one has and enjoys the value of having virtues. But if one has formed these virtues through significantly free exercise, then on infinitely many days one also has and enjoys the additional value of having virtues that were thus formed. That’s an infinite additional increment. So as long as the disvalue of the sufferings in this life was finite—which surely it was—it’s worth it.

Ad 2: The greater the sufferings that one endured courageously and the greater the sacrifices one made in love, the more fully one owns the resulting courage and love. For in more extreme exercises of these virtues, one has a greater opportunity to abandon the path of virtue, and one’s presence on that path is more truly one’s own. And this deeper ownership over one’s virtue—bearing in mind, of course, that all one has is a participation of God, and that grace is deeply involved—adds an additional value of virtue-ownership throughout an infinite number of future days. Hence, it adds an infinite amount of value, which is surely worth it.

Ad 3: This is probably the most serious worry. Start with this thought. God is choosing whether to snatch Judas up to heaven in the first moment of his existence, imposing on him a perfectly virtuous character, or to give Judas the opportunity to freely develop and own that character. A toy model for this an extended utility calculation. On the first option, we have an expected utility of

  • V(eternal unowned virtue),

where V is value. On the second option, we have an expected utility of

  • pV(eternal owned virtue) + (1 − p)V(Judas chooses vice)

where p is the probability that Judas would come through the crucible well. (Of course, this line of thought requires rejecting theological compatibilism and Molinism.) Here, V(eternal unowned virtue) and V(eternal owned virtue) are each infinite and positive. Plausibly, V(Judas chooses vice) is negative. Is it infinite? That’s not clear. One might think that on orthodox Christian views of hell, it is both negative and infinite. But that need not be the case. It could be that the suffering and vice in hell actually decreases from day to day, so that the total amount of suffering and vice over eternity is actually finite (think of how 1 + 1/2 + 1/4 + ... = 2).

If V(Judas chooses vice), the argument still isn’t over, but I will assume that V(Judas chooses vice) is finite—we could just build that into the theodicy. In that case, we can basically neglect V(Judas chooses vice)—when the other quantities are infinite, a finite subtraction is only going to be a tie-breaker.

So now the question is whether V(eternal unowned virtue) is bigger than or equal to pV(eternal owned virtue). And here it seems very reasonable simply to make a sceptical theist move. We don’t know what was Judas’ probability of coming through the crucible well. We don’t know exactly how V(eternal owned virtue) compares to V(eternal virtue). It could be that a day with owned value is three times as valuable as a day with unowned virtue. If so, then as long as p > 1/3, God’s giving Judas the opportunity for freely choosing virtue was worthwhile.

There are many objections, of course, that one can make. Here’s one that particularly comes to my mind: Wouldn’t it be better for God to first give people the opportunity to freely choose a virtuous character, but then if they refuse to do so, to impose that character on them? After all, at least some infants go to heaven after death. But they haven’t developed a virtuous character through the described kind of crucible. And so it seems that God imposes on them a virtuous character.

There are two things I’m inclined to say to this. First, there is a relevant difference between the case of imposing virtue on an infant and imposing virtue on someone who has chosen against virtue. Second, those who choose virtue own their virtue more fully if they had the possibility of not having that virtue at all.

Monday, March 20, 2017

Three levels of sex/gender

The biological understanding of male and female is something like this. Some species reproduce sexually. Some species that reproduce sexually exhibit a consistent difference in size between the two gametes that come together in sexual reproduction. In those species, the producer of the larger gamete is called “female” and the producer of the smaller gamete is called “male”. We can thus draw a distinction between a species having sexes, namely having respective producers of two different kinds of gametes, each of which is needed for sexual reproduction, and the species having male and female sexes.

Let me speak vaguely but heuristically. Human reproduction has a deep ethical and theological significance because it produces persons. Moreover, humans normally reproduce sexually (the exception of course being twinning). So it’s unsurprising if the existence of two sexes among humans has intrinsic ethical and theological significance. But the difference between male and female seems to have no intrinsic ethical or theological significance. It matters that there are two reproductive kinds, but that one of the two kinds produces a larger gamete than the other has no intrinsic ethical or theological significance.

But of course even though what defines the difference between male and female humans is the difference in gamete size, the actual differences between male and female humans are not in fact limited to differences of gamete size. Those humans that produce smaller gametes produce more of them, while those humans that produce larger gametes produce fewer of them and gestate offspring. Humans have “primary sex characteristics” that support differing ways of reproductive functioning.

Here is a thought experiment. Imagine earth* where there are humans*. To a cursory external examination, humans* live, look and behave just like humans, and have the same kind of sexual differentiation. One sex produces lots of gametes and the other relatively few. The sex that produces fewer gametes gestates offspring for nine months, has mammary-type glands that nourish offspring after gestation, is a little smaller on average, etc. But on earth*, it also turns out that the the sex that produces relatively few gametes produces the smaller gametes. (There may be evolutionary reasons why this is unlikely. But unlikely is not impossible.) Thus, on earth* male humans* fill the same biological roles as female humans do on earth, except at a near-microscopic level where the sizes of gametes become visible.

Now overlay on this the social level. This could go in multiple ways. It is easiest to imagine that on earth*, male humans* have the same social positions, and suffer from the same sorts of discrimination, as female humans do on earth. But it could in principle be reversed: it could be that the social position of male and female humans* is like that of male and female humans, respectively. Or it could be nullified: there could be no significant differences in social position.

This suggests that there are three levels to sex/gender:

  • The definitionally fundamental distinction between male and female in terms of gamete size.

  • Other biological differences—particularly with respect to reproductive functioning.

  • The social distinctions.

The first two tend to be lumped together as “sex” or “biological sex”, while the last gets called “gender”. But there really are three distinct levels. We might roughly call them: “biological gametic sex”, “biological functional sex” and “social gender”. Thus, among humans*, the connection between biological functional sex and biological gametic sex is the reverse of how it is among humans. So we now have three different senses of terms like “man”, “woman”, “male” and “female”.

Friday, March 17, 2017

Some paradoxes of reference


Liar-like:
  • one plus the biggest integer that can be expressed in English in fewer than fifty words
  • one; two; three; one plus the biggest integer mentioned in this list
  • one; two; three; one plus the last integer mentioned in this list
  • one plus the last integer mentioned in this list; two; three; one plus the first integer mentioned in this list
  • one plus this integer
Truthteller-like:
  • one; two; three; the biggest integer mentioned in this list
  • one; two; three; the last integer mentioned in this list
  • the last integer mentioned in this list; two; three; the first integer mentioned in this list
  • this integer
  • the square of this integer

Wednesday, March 15, 2017

Heaven

One of the things that most strengthens my faith is compelling accounts of heavenly happiness. I think there are at least two reasons why such accounts tend to strengthen faith. First, a compelling account of heavenly happiness rebuts the "sounds like fairy tale" objection to Christian faith. Second, a compelling account of heavenly happiness resonates with us in a way that gives us evidence that we are meant for a different kind of life than the one we have hear. I wish there were more sermons on heaven. And we philosophers also should work more on giving good accounts of what heaven might be like.

Tuesday, March 14, 2017

Disjunctive victimization?

Alice, Bob and Carl are suffering from a deadly disease. Alice possesses one dose of a medication necessary and sufficient to cure the disease. She has four relevant options. First there are:

  1. Use the medication on herself.
  2. Use the medication on Bob.
  3. Use the medication on Carl.

Option 1 is permissible. Options 2 and 3 are supererogatory. But what Alice actually does is:

  1. Destroy the medication.

Alice clearly did something wicked by failing to use the medication to save a life. But how do we describe this wicked deed?

It seems that Alice’s action was a fatal negligence of a duty towards herself, and a fatal negligence of a duty towards Bob and a fatal negligence of a duty towards Carl. But that makes it sound like three counts of fatal negligence, which is triple-counting the wrongful act.

I suppose what we can say is something like this: Alice neglected to use the medication to save a life. Whom did she act against? Maybe each of: herself, Bob and Carl. But we shouldn’t look at the action as the violation of three duties, but only of one duty, to use the medication to save herself, Bob or Carl. So she violated a single duty, to the tune of a single life, but that single duty was one she owed to three people.

Question 1: Does it follow that one can have a duty to a group which does not reduce to a duty to each member? For Alice surely doesn’t owe Bob that she save herself, Bob or Carl, and she doesn’t owe Bob that she save Bob, since she can permissibly save herself or Carl.

Answer: I don’t know. Maybe we can say:

  • Alice owes herself that if she doesn’t use the medication to save Bob or Carl, she use it to save herself
  • Alice owes Bob that if she doesn’t use the medication to save herself or Carl, she use it to save Bob
  • Alice owes Carl that if she doesn’t use the medication to save herself or Bob, she use it to save Carl.

And so Alice wrongs each of herself, Bob and Carl. A problem with this solution, however, is that it seems to triple counting Alice’s wrongdoing, by making it seem like she fatally wronged each of three people—but she is only responsible for a single death. Maybe, though, we can say that the duty to the three reduces to the three individual duties, but that the culpabilities don’t sum?

Question 2: Does the case provide an argument that one can wrong oneself? My above description of the case as one one where Alice owes it to herself, Bob and Carl that she save herself, Bob or Carl presupposes duties to herself. What can someone who thinks there are no duties to self say?

Answer: I don’t know. Maybe she can say: Alice owes Bob and Carl that she save herself, Bob or Carl. But it would be a little weird to think that by saving herself, Alice would be fulfilling a duty to Bob and Carl.

Final remarks: I am far from clear how to morally describe the case. I think the neatest description is one where a group is non-reducibly victimized, and where there are duties to self. But that may not be the only admissible description.

Instantaneous Newtonian gravitational causation at a distance?

It’s widely thought that Newtonian gravity, when causally interpreted, involves instantaneous causation at a distance. But I think this is technically not right.

Suppose we have two masses m1 and m2 with distance r apart at time t1. The location of m2 at t1 causes m1 to accelerate at t1 towards m2 of magnitude Gm2/r2. And this sure looks like instantaneous causation at a distance.

But this isn’t an instance of instantaneous causation. For facts about what m1’s acceleration is at t1 are not facts about how the mass is instantaneously at t1, but facts about how the mass is at t1 and at times shortly before and after t1: acceleration is the rate of change of velocity over time. Suppose that a poison ingested at t1 caused Smith to be dead at all subsequent times. That wouldn’t be a case of instantaneous causation, even though we could say: “The poison caused t1 to be the last moment of Smith’s life.” For the statement that t1 is the last moment of Smith’s life isn’t a statement about what the world is instantaneously like at t1, but is a conjunctive statement that at t1 he’s alive (that part isn’t caused by the poison) and that at times after t1 he’s dead (that part is caused by the poison, but not instantaneously). Similarly, m1’s velocity (and position) at times after t1 is caused by m2’s location at t1, but m1’s velocity (or position) at t1 itself is inot.

Let’s call cases where a cause at t1 causes an effect at interval of times starting at, but not including, t1 a case of almost instantaneous causation. In the gravitational case, what I have described so far is only almost instantaneous causation. Of course, people balking at instantaneous action at a distance are apt to balk at almost instantaneous action at a distance, but the two are different.

The above is pretty much the whole story about instantaneous Newtonian causation if one is not a realist about forces. But if one is a realist about forces, then things will be a bit more complicated. For m2’s location at t1 causes a force on m1 at t1, which complicates the causal story. On the bare story above, we had m2’s location causing an acceleration of m1. When we add realism about forces, we have an intermediate step: m2’s location causes a force on m1, which force then causes an acceleration of m1. (There might even be further complications depending on the details of the realism about forces: we may have component forces causing a net force.) Now, when the force-at-t1 causes an acceleration-at-t1, this is, for the reasons given above, a case of almost instantaneous causation. But the causing of the force-at-t1 by the location-at-t1 of m2 is a case of genuinely instantaneous causation.

But is it a case of causation at a distance? It seems to be: after all, the best candidate for where the force on m1 is located is that it is located where m1 is, namely at distance r from m2. (There are two less plausible candidates: the force acting on m1 is located at m2, and almost instantaneously pulls on m1; or it’s bilocated between the two locations; in any case, those candidates won’t improve the case for instantaneous action at a distance.) But here is another problem. The force on m1 is not produced by m2. It is produced by m1 and m2 together. After all, the Newtonian force law is Gm1m2/r2. (It is only when we divide the force by m1 to get the acceleration that m1 disappears.) Rather than m2 pulling on m1, we have m1 and m2 pulling each other together. Thus, m2 instantaneously partially causes the force on m1 at a distance. But the full causation, where m1 and m2 cause the force on m1, is not causation at a distance, because m2 is at the location of that force.

In summary, the common thought that Newtonian gravitation involves instantaneous causation at a distance is wrong:

  • If forces are admitted as genuine causal intermediates (“realism about forces”), then we have almost instantaneous causation of acceleration by force (moreover, not at a distance), and instantaneous partial causation of force at a distance.

  • Absent force realism, we have almost instantaneous causation at a distance.

Monday, March 13, 2017

Life

Accounts of biological life characterize it by lists of features such as “reproduction, metabolism, functional organization, growth, responsiveness to the environment, movement, and short- and long-term adaptations” (SEP s.v. life). But Jewish, Christian and Muslim theists have reason to worry about such accounts of life in the light of the fact that our scriptures present God as the paradigm of a living being.

Here are some options:

Option 1: Modify one’s theology to make God fit with something pretty close to one of the biological accounts of life. Mormonism is a fairly radical example of this. A more moderate version might be some version of process theology, though one may need to jettison some features, like metabolism and growth.

Option 2: Trinitarians have this option available: The Son proceeds from the Father and the Spirit from the Father and/through the Son and these processions could count as reproduction. Moreover, because Trinitarian processions multiply persons but the resulting persons are one God, Trinitarian reproduction has an internality that might count as a kind of growth—not that the divine essence grows, but that the number of persons of the one God grows. This solution would have the important consequence that the Old Testament texts that present God as living are proto-Trinitarian. Obviously, this solution is unlikely to be attractive to Jews and Muslims, though there may be some Kabbalistic analogue that might appeal to some Jews. Moreover, unless one adopts some version of process theology, this solution still requires one to drop a number of the features in traditional accounts of biological life, such as metabolism, movement and adaptation.

Option 3: Replace the biological accounts of life with something radically different which makes God a paradigm instance of life. Here are three such possibilities for characterizing life:

A. Living things are ones that have some mental property like consciousness or purposefulness.

B. Living things have teleology.

C. Living things are ones that have a well-being, that are capable of being well.

Suboption A is pretty radical: it requires either saying that plants have a mental life or that plants aren’t alive. I think it’s not that crazy to say that plants have something like mental life. Maybe they are aware of their environment in a way that goes robustly beyond the mere data processing of a digital thermometer. And it seems plausible that one can ascribe a certain kind of purposefulness to plant processes.

Suboption B is pretty close to the purposefulness variant of suboption A, but teleology is a more general concept than mental purposefulness. For me, the main difficulty with suboption B is that I think all substances have teleology. And I don’t want to extend life to elementary particles. But those who do not think that teleology extends to all substances might like Suboption B.

Suboption C is, of course, related to Suboption B. I have the same worry about C as about B: I think all substances that have teleology have a well-being. Elementary particles have well-being—the only difference between them and organic substances is that as far as we can tell, elementary particles are always well. This is of course very controversial, and those who do not accept it may like C.

There are, no doubt, other options and suboptions. I am attracted to Options 2 and 3A.

Priors, justification and rationalism

The rationalism of Leibniz and Spinoza worked like this: We figure out fundamental necessary metaphysical principles, and these principles determine everything else of necessity (with some qualifications on the Leibniz side as to the type of necessity).

But another rationalism is possible: We figure out fundamental necessary metaphysical principles, and these principles determine the basic probabilistic structure of reality. In Bayesian terms, the fundamental metaphysical principles yield the prior probabilities. A version of this was Descartes’ project in the Meditations.

And there is reason to engage in this probabilistic rationalist project. We cannot get out of the need to have something like prior probabilities. Moreover, priors need epistemic justification. Consider an empirical claim p that we assign a high enough credence for belief to, say 0.99, on the basis of total evidence e. Thus, P(p|e)=0.99. It follows by the axioms of probability that P(p ∨ ¬e)≥0.99. Hence we have a high enough prior credence for belief in p ∨ ¬e. Surely assigning a credence of 0.99 to something requires epistemic justification. Moreover, surely (though people who don’t like closure arguments may not like it) if we have posterior justification when we believe p, we have posterior justification when we believe the obviously entailed claim p ∨ ¬e. But this justification did not come from e. For P(p ∨ ¬e|e)=P(p|e)=0.99 and we have seen that P(p ∨ ¬e)≥0.99, so e is not evidence for p ∨ ¬e (in face, typically e will be evidence against this disjunction). Since e is our total evidence, the justification had to be there in the first place.

Thus we need epistemic justification for our priors. The priors encode genuine information about our world, information that we are justified in possessing. Where do we justifiedly get this information from? We don’t get it through logic, pace logical probability accounts. Metaphysics is one potential answer to this question and exploring this answer gives us good reason to engage in the probabilistic rationalist project. Another option is that the priors are a kind of innate knowledge built into our nature—my Aristotelian Bayesianism is a version of this.

Thursday, March 9, 2017

Multiple levels of multiple realizability

We could have sophisticated beings who reason about the world via numerical Bayesian credences. But we could also have sophisticated beings who reason in some other way—indeed, we are such beings. And there is one sophisticated being who reasons about the world via omniscience. This suggests that reasoning and agency are multiply realizable at multiple levels, including:

  1. brain/mind architecture

  2. algorithms implementing general reasoning and representation strategy

  3. general reasoning and representation strategy.

Each level is an abstraction from the previous. So now we have a very deep question: Is there a fourth level that abstracts from the third, to get the concept of reasoning as such? Or are the various general reasoning and representation strategies unified analogically, say by similarity to some primary case? And if so, what is the primary case? Omniscience? Logical omniscience plus numerical Bayesianism?

Wednesday, March 8, 2017

A pessimistic thought about epistemic rationality

The more I think about relatives of the Doomsday Argument and my insect argument, the more I become suspicious of both the self-sampling and the competing self-indication assumptions.

Both assumptions require one to assign non-zero probabilities to metaphysically impossible hypotheses about where I am located in spacetime, such as the hypothesis that I was born in the 19th century, the hypothesis that I am a non-human or the hypothesis that it is now a Wednesday. It is usual in the discussion of these hypotheses not to worry much about such issues of metaphysical impossibility. The thought is that we are doing epistemology, not metaphysics.

Moreover, it seems reasonable to assign a credence 1/10 to the proposition that the hundredth digit of π is 3 when one hasn’t calculated that digit, even though one knows that the proposition is either necessarily true or necessarily false.

Perhaps my Aristotelian meta-epistemology can help, though. What if the right way to assign credences is not some abstract “rational” way to do so, but rather the human way—the way that our human nature calls us on us to? Our human nature specifies how we should function within a certain broad range of conditions. But outside of that range, human nature may not specify how we should function. Our nature specifies normal human locomation in earth gravity, but specifies nothing about what normal human locomation out in space should be like. Likewise, our nature specifies normal human credential behavior in many circumstances, but need not specify human credential behavior in outlandish cases like Doomsday.

Of course this raises the very hard question of which cases are within the range of cases where our nature specifies credential behavior and which are not.

Sunday, March 5, 2017

Super-simple fractal terrain generator

Here's a very simple algorithm for generating random terrains: Start with a equilateral triangle in the x-y plane. Add a uniformly and symmetrically distributed random z-offset to each vertex. Bisect each resulting edge and add a random z-offset at the newly added point, half of the magnitude of the random offsets earlier. Repeat several times.

The algorithm is no doubt known, but some quick searches for terrain generation algorithms didn't turn it up, so I am posting for people's convenience.

There are some artifacts at internal triangle boundaries that better algorithms presumably don't have, but the algorithm is super simple to implement, and because it is based on triangles it directly makes a triangular mesh. Here is some code which does this, starting with a hexagon divided into six equilateral triangles, and putting out an STL file.