Monday, September 29, 2014

Two kinds of desire strength

Suppose I am designing a simple vacuuming robot not unlike a Roomba, but a little more intelligent. I might set up the robot to have multiple drives or "desires" including the drive to maintain well-charged batteries and to maintain a clean floor. The robot, then, will use its external and internal sensors to obtain some relevant pieces of information: how much dirt remains on the floor, how low its battery charge is and how far away from its charging station it is. I now imagine the processor uses the dirt-remaining value to calculate how much it "wants" to continue vacuuming and the battery charge sensor and the distance from the charging station to calculate how much it "wants" to recharge. These two want-values, together with any others, then go to a decision subroutine, whose specifications are as follows:

  1. When one want-value is much greater than the sum of all the others, go for that one.
  2. When (1) is false, choose randomly between the want-values with choice probabilities proportioned to the want-values.
(Why not simply go for the strongest desire? Maybe because some randomization might prevent systematic errors, like areas distant from the charger that never get cleaned.)

Suppose now that the robot suffers from a hardware or software failure that in high temperature conditions makes the decision subroutine count the floor-cleaning want at double weight. Thus the robot cleans the floors more when it's hot in the house, even when it is short of battery charge.

Suppose it's a hot day, and the robot's sensor calculations give respective values 2.2 and 4.0 to the floor-cleaning and battery-recharge wants. Then in one perfectly intelligible sense the battery-recharge want is almost twice as strong as the floor-cleaning want. But most of the time in this state, the robot will continue to clean the floor, and in that sense the floor-cleaning want is somewhat stronger than the battery-recharge want.

We can and should distinguish between the nominal desire strengths, which are 2.2 and 4.0, and the effective desire strengths, which are 4.4 and 4.0, due to the buggy way the decision procedure handles the cleaning want when the temperature is high. We might also, in a more theory-laden way, call the desire strengths as they feed into the decision subroutine the "content strengths" and the desire strengths as they drive the decision the "motivational strengths."

In fact, what I said about nominal and effective strengths can be generalized to nominal and effective desires full stop. After all, we can imagine a bug where in the decision procedure under some conditions the memory location holding the cleaning-want value is overwritten with the memory location holding the present temperature. In positive temperature situations, this can result in the creation of an effective desire to clean the floors in the complete absence of a nominal desire for that, and in negative temperature situations, it can create an effective desire not to clean the floors, even though there is a nominal desire to clean them.

Surely our own decisions are subject to a similar distinction. Even if in fact the nominal and effective strengths of our desires are always equal—a very implausible hypothesis, especially in light of the apparent ubiquity of akrasia—the two could come apart.

By definition, one does tend to act on the effective desires and the effective desire strengths. But surely it is nominal desires and nominal desire strengths that more affect how one should act by one's own lights. When a discrepancy happens, it is a malfunction, a failure of rationality.

If one wants to connect this post with this one, the distinction I am making here is a distinction between two kinds of degrees of preference on the content side. So if that post is correct, we really have a three-fold distinction: the conscious intensity, the content (or nominal) strength and the motivational (or effective) strength.

I suspect that when we think through this, some Humean theses about action and morality become much less plausible.

Thursday, September 25, 2014

Possibility, probability and propensity

I have defended at length the idea that metaphysical possibility is grounded in the causal powers of things. It just occurred to me that this view is very naturally connected to the view that objective probability is grounded in causal propensities. We can think of probability as a measure of the degree of possibility, and of possibility as an attenuated kind of probability. If we see things in this very natural way—and hopefully its naturalness isn't just due to alliteration—then we have a unified and mutually supporting story about probability and possibility. Both are grounded in causal powers, but differently. Possibility is grounded in the bare existence of causal powers. Probability is grounded in the propensities of causal powers. If we have reason to accept one view, that tends to give us reason to accept the other.

Clearly anything that's made possible by the causal powers account of possibility—let's call this "causally possible"—is possible. So the only question about the causal powers account of possibility is whether it captures all possibilities. Suppose some things are possible but not causally possible. Then we can ask about their probabilities. If probabilities are propensities, then we should say that such things have zero probability, since nothing has a propensity to produce them. And not just the kind of "numerical zero" that classical probability assigns to a sequence of infinitely many heads, but the deep kind of zero that is had by the probability that one equals two. It's plausible, though, that things with this deep zero probability just can't happen. So the propensity account of probability neatly suggests the causal powers account of possibility.

And the converse is also plausible. If all possibilities are causal possibilities, it is very natural to measure the degree of their possibility by the causal propensities.

Of course the above is very vague. It may be that particular details of how one works out a causal powers account of possibility don't sit well with the particular details of a propensity account of objective probability.

Monday, September 22, 2014

Low probability explanations

Some people think that for C to explain E, P(E|C) must be high. This is false. Suppose two events E1 and E2 have probabilistic explanations, and we understand that the events are independent. Then we understand why E1 occurs and why E2 occurs, and we also understand why their conjunction occurs. But of course their conjunction has lower probability than either of them, and iterating this argument we get to a conjunctive event such that we understand why it occurs even though its probabilistic explanation is a quite low probability one.

Friday, September 19, 2014

Evolution and the Principle of Sufficient Reason

This is an oldish argument, inspired by a student comment, but I kind of like my present formulation of it. Start with this fine inductive argument:

  1. All the known explanations of present species are evolutionary.
  2. So, all the explanations of present species are evolutionary.
But (2) isn't all that the evolutionary biologist claims about present species. She claims more strongly:
  1. All the present species have evolutionary explanations.
Claim (3) is stronger than claim (2). Let's suppose that half of the present species have evolutionary explanations and the other half have no explanations at all. Then (2) is true, but (3) is not.

We could derive (3) from (2) if we had the further thesis:

  1. All the present species have explanations.
Indeed, (3) is equivalent to the conjunction of (2) with (4). But the evidence in (1) does not do anything to support (4). It only supports (2).

We could get scientific support for (4) as follows. Randomly samples species, and make sure that we can find an explanation for each randomly sampled species. But we haven't done this.

Yet, I say, we know (3) to be true, and hence we know (4) to be true as well, since (3) obviously entails (4) and this doesn't look like one of the exceptional cases that are counterexamples to closure.

But how do we know (4) to be true? I think a priori. And the best non-ad hoc story about that is that we derive it from the Principle of Sufficient Reason.

Thursday, September 18, 2014

Trying and intending

Suppose I have a sore knee and a doctor asks me to try to lift my leg to see if I can do so. So I try, and let's say I succeed. Did I intend to lift my leg? It seems not. It seems that I intended to lift my leg if and only if I could, as a means to the doctor's being able to diagnose my knee. But this is very strange. I tried and I succeeded, but I didn't intend my success!

Maybe I didn't really try to lift my leg? Maybe I only tried to lift it if and only if I could. But that doesn't seem right. The doctor didn't want to see the effects of my trying to "lift my leg if and only if I could", but wanted to see the effects of my trying to lift my leg.

I am not sure what to make of this kind of case.

Wednesday, September 17, 2014

Animals and Animalia

If tauntauns (i.e., creatures relevantly like this) existed, they would be animals. If tauntauns existed, they wouldn't be members of the kingdom Animalia, because the kingdom Animalia is a clade, and Tauntaun's would presumably be products of alien evolution rather than descendants of earth animals. Since it's possible for tauntauns to exist, it follows that it's possible for there to be animals that aren't members of the kingdom Animalia.

Another example. Suppose a species of water plant evolved to have descendants whose behavior and build closely resembles a hippotamus. The resulting species would still be a member of the kingdom Plantae, since the Plantae are a clade, and not of Animalia. But I think it would be an animal. Would it be a plant as well? Maybe—maybe it would be both plant and animal.

The concept of an animal goes beyond actual earth biology. Now, here's an interesting question. We are rational animals. Could there be rational embodied non-animals, e.g., rational plants that, unlike the hippopotamus-like plants of my example, are not animals? There would be little reason for a non-animal to evolve intelligence, but an extremely unlikely series of chance mutations is not impossible just because it's unlikely.

Are questions about what is and what isn't an animal substantive questions? Or is it just a matter of drawing arbitrary non-joint-carving boundaries?

Tuesday, September 16, 2014

Reproducing for the child's sake?

Suppose that you are hooked up to a button which, if pressed, will induce in you a desire for a flash of green light followed by a flash of green light. Plausibly, if you will have a desire for something neutral or good, that gives me a reason to fulfill that desire. Assume that you consent to my pressing the button as well as to my not pressing it, but you have no desire either way. I now press the button, on the grounds that:

  1. you will have a desire to see a green flash, and by pressing the button I will have fulfilled that desire of yours.
But this is fallacious practical arguing. Granted, given that I will press the button, you will have a desire for a green flash, and so I have reason to press the button to give you that green flash. But whether I am to press the button is precisely what the practical question is about. And if I don't press the button, there will be no desire. I cannot use a desire of yours that is conditional on my decision to provide myself with a reason to press the button. That would be like lifting myself by my bootstraps.

Another case. Normally, if I know that I will make you a promise, that gives me a reason to do something that makes me able to fulfill of that promise. Suppose now that I am deliberating whether to promise you to draw a pig. Standing by is Jim, who I know will hand me a piece of paper and a pink crayon if and only if he hears me promise to you that I will draw a pig. So I promise you to draw a pig on the grounds that:

  1. I will shortly be subject to a promise to draw a pig, and by making the promise I make myself able to fulfill the promise, as Jim will supply me with the wherewithal.
But that is just plain silly. Given a decision to promise to draw a pig, it makes perfect sense for me to attempt to get the wherewithal. But whether to promise to draw a pig or not is precisely what is at issue. It would be rationally circular to reason from the promise in deciding to make the promise.

Now a third case. A couple has a child on the basis of the thought that if someone exists or will exist, then one has reason to provide them with a good, and

  1. The child will exist, and by procreating we will be providing the child with various goods, including especially life.
But it seems that this reasoning is as practically fallacious as (1) and (2). Of course, given that the child will exist, the provision of life to the child is a good thing. But whether the child is to exist is precisely what is at issue in the deliberation.

If this is right, then one cannot procreate for the child's sake.

One may be able to procreate in order that the world contain the good of the child's life, but that is an impartial good, not a good to the child. (And there are some Kantian worries about this—it seems to make of the child a means.)

Monday, September 15, 2014

Needing a cause

I've been re-reading Samuel Clarke's cosmological argument. Here's a version of his argument:

  1. Anything that has a cause needs a cause.
  2. The sum of things that each need a cause needs a cause.
  3. Anything that exists and needs a cause has a cause.
  4. The cause of a sum of things that each need a cause is outside of the sum.
  5. There is a sum of all caused things.
  6. So, there is a cause of the sum of all caused things. (1-3,5)
  7. So, the sum of all caused things has an uncaused cause. (5,6)
I think the trickiest and most interesting thing in this argument is (2). I suppose the intuition here is that you're not going to get what you need simply by piling up needy beings.

Where I have "needs a cause", Samuel Clarke has "is dependent". That makes his analogue of (3) trivial, but it makes his analogue of (1) more controversial.

Friday, September 12, 2014

Faith in Christ without having heard the Gospel

There is no salvation apart from faith in Christ. But what about those who haven't heard of Christ? A standard story is that they can have a spiritual relationship with Christ even though they do not know that they are having a relationship with Christ. They can be "anonymous Christians."

But faith is supposed to be an interpersonal relationship. The kind of hidden mysterious relationship that falls under the head of anonymous Christianity seems to fall short of the best kind of interpersonality, and seems not to be very incarnational in character. Now, there is nothing wrong with saying that although it falls short of the best kind of interpersonality, it is sufficient as faith. But I want to explore a dimension that gives more of an interpersonal and incarnational aspect to being an anonymous Christian.

Suppose that our anonymous Christian is blessed by being in a community with other anonymous Christians. They are all, unbeknonwst to themselves, animated by the grace of Christ. They are all, unbeknownst to themselves, members of the body of Christ. Thus in relating to one another they are relating to Christ. But their relations to one another do have the right kind of interpersonality and incarnational character. The presence of Christ through other anonymous Christians in their community—maybe even everyone in the community is an anonymous Christian—make their implicit faith in and love of Christ much more of an interpersonal relation than it would otherwise be. And of course in this regard they are not that different from explicit Christians, since so much of what we know of Christ is based on what we know of people whose lives are made radiant by Christ's grace.

An unfinished world

Yesterday, at a prayer service responding to various evils, the chaplain talked of us as living in an unfinished world. I was very struck with this. I think that conceptualizing our world as unfinished can really help with the problem of evil.

The world is in construction. It's a mess. That's what construction sites are like. But we have the privilege of being in on the construction.

Tuesday, September 9, 2014

Nostalgia: Use Palm infrared keyboard with Android phone

I am probably the only person interested in this sort of thing, but in case anybody has an old PalmOne infrared keyboard and for the sake of nostalgia or convenience or whatever wants to use it with a newer device, I wrote up instructions on how to interface the keyboard via Bluetooth.

Talking of nostalgia, doesn't the phenomenon suggest that there is something not quite ideal about our current relationship to the past? The past is really real. So why feel nostalgia, when our past actions and experiences are really real? In heaven, perhaps, our memory will be so vivid that our past lives--transformed in a hindsight illumined by the beatific vision--will be fully present to us.

I couldn't be a god, so God exists

Zeus is a godlike being. However, if God created Zeus with all of Zeus's godlikeness, Zeus wouldn't be a god. Zeus would merely be a godlike being. In the world where God created Zeus, Zeus would be infinitely more like us than like the highest being—namely, God—in that world. But in the world of Greek mythology, where there is no God, Zeus would be a god.

Being a god is, I think, partly a relational property. While one might imagine a hierarchy of gods, the gods will be approximately at least as similar to each other in respect of their divine attributes (intelligence, power, etc.) than to us. But God is a god, and Zeus is infinitely more like us than like God.

With this in the background, here is an interesting argument:

  1. Pruss couldn't be a god.
  2. If Pruss could exist in the absence of God, Pruss could be a god.
  3. So, Pruss couldn't exist in the absence of God. (1,2)
  4. Pruss exists.
  5. So, God exists. (3,4)

Premise (1) should be obvious to you. Premise (2) relies on the following line of thought. Surely if I could exist in the absence of God, I could grow to have all the superpowers that Zeus is said to have, and to exceed all other intelligent beings very, very far. I would be godlike, and would have nobody close to on par, and so—horrors!—I would be a god. And while premise (4) is obvious to me, it should be pretty plausible to you, too.

Monday, September 8, 2014


Over time, it has come to be the case that while I tell a significant number of people—my students and children—what to do, there are few people who tell me what to do. My Department Chair rarely tells senior faculty what to do—though he does make suggestions. The higher administration may pass policies, but rarely do they tell tenured senior faculty what to do, in the way I tell my students. My parents advise but don't command.

All this is an unfortunate state of affairs. One of the human virtues is that of obedience, a virtue particularly well suited to teaching humility and guarding from pride and arrogance. I confess to finding the exercise of authority to have a fair amount of pleasure about it, and to enjoying not having much authority exercised over me. And while there are genuine goods here, and goods are to be enjoyed, my enjoyment is nourished by and nourishes vices as well.

It is not uncommon for this to happen as one ages. As one gains seniority, the ratio of authority exercised over one to authority one exercises often shrinks. But the greatest of the vices is pride, and obedience is a genuine virtue. It is important to fight the authority imbalance.

Being a religious superior who had few people to tell him what to do, St Philip Neri talked of the value of at least having his doctor to obey. Those of us in the envied but aretaically unenviable position of commanding much more than we are commanded need to make an effort to come to be under various authorities, to seek out activities where one will be under the authority of others, however much that may grate the old Adam. Join a club or fraternal organization but don't be an officer. (Particularly valuable might be a setting where much younger people get to tell one what to do.) Get a personal trainer. Serve in one's parish while avoiding positions (official or unofficial) of authority, except when one's parish really needs one.

Perhaps such things can help develop a habit of wanting to obey rather than be obeyed, a habit that will make one's exercise of authority always be appropriately reluctant.

This has snuck up on me.

Orate pro me.

Thursday, September 4, 2014

From the Principle of Sufficient Reason to causal finitism

Causal finitism says that nothing can have infinitely many things in its causal history. Suppose causal finitism is false. Then surely the following scenario is possible:

  1. There has always been a lamp.
  2. There is a backwards infinite sequence of flips of the lamp switch at times t−1>t−2>t−3>....
  3. Each time the switch was flipped, the lamp state flipped between on and off.
  4. All lamp state changes are explained by switch flips, and are not overdetermined by any other causes.
Call this story the "Reversed Thomson's Lamp" (RTL). If RTL holds, the Principle of Sufficient Reason is false. To see this, suppose that the lamp is on right after t−1. Then it's on right after tn for all odd n. But there is no explanation why it's on right after tn for all odd n; it could have instead been on right after tn for all even n. It would be circular to explain its being on after the odd-numbered times in terms of its being off after the even-numbered ones, since by the same token its being off after the even-numbered ones would be explained by its being on after the odd-numbered ones. If one had overdetermination, one could explain things in terms of the overdetermining causes, but that would go against (4).[note 1]

So if the Principle of Sufficient Reason is necessarily true, RTL is impossible, and hence causal finitism is true.

Wednesday, September 3, 2014

Forming an infinity step-by-step

Suppose I am assigned to write a book with infinitely many pages. Luckily for me, the past is infinite. Then I could have accomplished the task on a leisurely schedule by having written a page every decade.

But the odd thing is that then the task will then have always been finished! For in every past, present or future decade, it is true that I've already written infinitely many pages.

Yet the task of writing a set size of book is surely a paradigm of a task done step-by-step. And it is a central feature of doing a task step-by-step that the task wasn't always completed. So the task of writing an infinite book wasn't always completed, and yet it was always completed, a contradiction.

Hence, the task of writing an infinite book a page at a time is impossible.

The best response I can think of is to deny that writing a book of a given size a page at a time is always a task done step-by-step. It's true for finite sizes, but need not be true for infinite ones. Maybe the problem is that it's not a possible task (this thought is inspired by Richard Gale's comments on Zeno paradoxes).

Tuesday, September 2, 2014

Short laptop desk made from two Ikea Lack side tables

I wanted a shortish laptop desk for use while sitting on the sofa.  Ikea had Lack tables on sale for five dollars.  I bought two and made this little table with a shelf out of them.  My instructions for the build are here.

As always in such things, there are fun metaphysics questions to ask.  I first built an ordinary Lack table out of one of the two kits I bought.  I used it for a couple of days to figure out the height I wanted for the final table (I tried putting a Settlers of Catan box on it, and the laptop on that--too high--and I tried putting a second Lack tabletop on it--just right).  Then I built the new table.  Now imagine that I proceeded as follows (I didn't--I used the legs from the other kit instead, as it happened).  After building the original table, I cut segments off the bottoms of the legs, thereby shortening the legs.  That wouldn't destroy my table, surely.  I would just have a table with shorter legs.  I then attach the segments to the second tabletop, and then glue that on top of the first.  Would I still have the same table as I started with, albeit no longer a Lack table, even though the tabletop of the first table had become a shelf?  What if instead the tabletop of the first table become the top of the new table?  That would require more disassembly, though. 

Also, although that's not how I did it, I could have started with two pre-made Lack tables, shortened the legs of one, and glued it on top of the other.  Would the two tables have been destroyed, replaced by table parts?  Would the two tables have continued to exist, but now being mere table parts instead of tables?  Or would the two tables have continued to exist, and to be tables, but they would now be a part of a new, third table, giving yet another counterexample (besides, say, Richard Gale's doggy door) to the principle that no object of a kind K can be a proper part of an object of kind K?  Would it make a difference if they were joined by Velcro instead of glue?  It would be odd if the exact choice of fasteners mattered.

Would it matter whether I used them separately?  Or hoped to do so but never did?

There are also fun metaphysics questions to ask about the parts which came in the Ikea box.  It is very natural to say that those parts in the box are the parts of a Lack table.  But what if they are never assembled?  Does that mean that the Lack table exists in the box, albeit in disassembled form?  What if I build two ordinary Lack tables, but mix up the parts and screw on the legs from each set into the tabletop from the other set?  Are there now four tables, two in disassembled form (that they are screwed into each other--Lack tables normally only use four double-sided screws to put together, and the legs can be easily untwisted from the top) and two new ones assembled?  That doesn't sound right.  So maybe the kit contains the parts for a Lack table, but the parts of a Lack table only if a Lack table is later made precisely of them.

All these questions are fun, but in Sider's sense they are non-substantive.  But questions about existence and identity are substantive.  I conclude that I made no tables.  (Obviously, I've switched from carpentry language to metaphysics language somewhere in the post.)  I just rearranged some fields or particles.

Monday, September 1, 2014

Extracting raw data from the Mindflex toy EEG

Last night I posted a full Instructable on how to extract raw data from the Mindflex toy EEG via Bluetooth (headsets can be bought for $15 on ebay and you need one or two $10 HC-06 Bluetooth modules), and indeed how to make it work pretty much like the more expensive Mindwave Mobile (complete software compatibility as far as I can tell if you initialize the toy with an app I link to in the instructions).

You need to make four solder connections, and jump through a few hoops to set up the Bluetooth module.

Good educational project for those with kids.

Follow the instructions at your own risk.  Make sure the headset isn't wired to anything connected to mains while it's on.