Category Archives: Science

A Guide to Reality, Part 13

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Chapter 8 of Alex Rosenberg’s The Atheist’s Guide to Reality: Enjoying Life Without Illusions is called “The Brain Does Everything Without Thinking About Anything At All”. Without thinking about anything at all? That sounds like another of Rosenberg’s rhetorical exaggerations.

He grants that it’s perfectly natural for us to believe that our conscious minds allow us to think about this and that. Yet he claims that science tells us otherwise:

Among the seemingly unquestionable truths science makes us deny is the idea that we have any purposes at all, that we ever make plans — for today, tomorrow or next year. Science must even deny the basic notion that we ever really think about the past and the future or even that our conscious thoughts ever give any meaning to the actions that express them [165].

But despite this claim about science and the title of the chapter, Rosenberg doesn’t really “deny that we think accurately and act intelligently in the world”. It’s just (just!) that we don’t “do it in anything like the way almost everyone thinks we do”. In other words, we think but we don’t think “about”.

Before getting to his argument against “aboutness”, Rosenberg offers the observation that science is merely “common sense continually improving itself, rebuilding itself, correcting itself, until it is no longer recognizable as common sense” [167]. That seems like a correct understanding of science; it’s not as if science is a separate realm completely divorced from what’s called “common sense”. When done correctly, science is a cumulative process involving steps that are each in turn commonsensical, i.e. based on sound reasoning or information:

Science begins as common sense. Each step in the development of science is taken by common sense. The accumulation of those commonsense steps … has produced a body of science that no one any longer recognizes as common sense. But that’s what it is. The real common sense is relativity and quantum mechanics, atomic chemistry and natural selection. That’s why we should believe it in preference to what ordinary experience suggests [169].

So, if you have a mental image of the Eiffel Tower or suddenly remember that the Bastille was stormed in 1789, ordinary introspection suggests that you’re having a thought about Paris. But, according to Rosenberg, that’s a mistake. Assuming that this thought of yours that’s supposedly about Paris consists in or at least reflects activity in your brain (the organ you use to think), that would imply that there must be something in your brain that represents Paris. We know, however, that any such representation isn’t a tiny picture or map of Paris. Brain cells aren’t arranged like tiny pictures.

But perhaps there’s a kind of symbol in your brain, an arrangement of neurons that your brain somehow interprets as representing Paris? Rosenberg rejects this possibility, arguing that any such interpretation would require a second set of neurons:

[The second set of neurons] can’t interpret the Paris neurons as being about Paris unless some other part of [the second set] is, separately and independently, about Paris [too]. These will be the neurons that “say” that the Paris neurons are about Paris; they will be about the Paris neurons the way the Paris neurons are about Paris [178]. 

Rosenberg argues that this type of arrangement would lead to an unacceptable infinite regress. There would have to be a third set of neurons about the second set, and so on, and so on.

I confess that I’m having trouble understanding why the regress is necessary. In Rosenberg’s notes, he references a book called Memory: From Mind to Molecules, by the neuroscientists Larry Squire and Eric Kandel, which he says explains “how the brain stores information without any aboutness”. Maybe it’s clearer there.

However, if we grant that Rosenberg’s argument is correct and one part of the brain interpreting another (symbol-like) part of the brain would require an impossible infinite regress, it still seems questionable whether he has shown that nothing in the brain can be about anything. What his argument will have shown is that one part of the brain can’t interpret some other, symbolic part of the brain. Perhaps thoughts can be “about” something in some other way.

Rosenberg next offers an interesting account of how our brains work. Briefly put, human brains work pretty much like the brains of sea slugs and rats. Scientists have discovered that all of us organisms learn by connecting neurons together. Individual neurons are relatively simple input/output devices. Link them together and they become more complex input/output devices. The key difference between our brains and those belong to sea slugs and rats is that ours have more neurons and more links.

When a sea slug is conditioned to respond a certain way to a particular stimulus (like one of Pavlov’s dogs),

[the training] releases proteins that opens up the channels, the synapses, between the neurons, so it is easier for molecules of calcium, potassium, sodium and chloride to move through their gaps, carrying electrical charges between the neurons. This produces short-term memory in the sea slug. Training over a longer period does the same thing, but also stimulates genes in the neurons’ nuclei to build new synapses that last for some time. The more synapses, the longer the conditioning lasts. The result is long-term memory in the sea slug [181].

The process in your brain was similar when you learned to recognize your mother’s face. Rosenberg cites an experiment in which researchers were able to temporarily disable the neurons that allowed their subject to recognize her mother. Since she still recognized her mother’s voice, she couldn’t understand why this stranger sounded just like her mother.

Rosenberg concludes that there is nothing in our brains that is “about” anything:

None of these sets of circuits are about anything….The small sets of specialized input/output circuits that respond to your mom’s face, as well as the large set that responds to your mom [in different ways], are no different from millions of other such sets in your brain, except in one way: they respond to a distinct electrical input with a distinct electrical output….That’s why they are not about anything. Piling up a lot of neural circuits that are not about anything at all can’t turn them into a thought about stuff out there in the world [184]. 

Of course, how the activation of neural circuits in our brains results in conscious thoughts that seem to be “about” something remains a mystery. Today, for no apparent reason, I had a brief thought about Roxy Music, the 70s rock band. Maybe something in my environment (which happened to be a parking lot) triggered that particular mental response. Or maybe there was some seemingly random electrical activity in my brain that suddenly made Roxy Music come to mind. 

I still don’t see why we should deny that my thought this afternoon was about Roxy Music, even if the neural mechanics involved were quite simple at the cellular level. If some of my neurons will lead me to answer “Roxy Music” when I’m asked what group Bryan Ferry was in, or will get me to think of Roxy Music once in a while, perhaps we should accept the fact that there are arrangements of neurons in my head that are about Roxy Music.

Philosophers use the term “intentionality” instead of “aboutness”. They’ve been trying to understand intentionality for a long time. How can one thing be “about” another thing? Rosenberg seems to agree that intentionality is mysterious. He also thinks it’s an illusion. Maybe he’s right. In the last part of chapter 8, he brings computer science into the discussion. That’s a topic that will have to wait for another time.

Bacteria Are Our Friends, Except When They’re Not

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It’s good to remind ourselves occasionally that we human beings are little worlds of a sort. Each of our bodies is composed of trillions of cells (about 40 trillion, based on a recent estimate), each going about their individual business, and many more microorganisms, mainly bacteria, each going about their business too.

I’m not sure why it’s good to remind ourselves of this fact, but it seems like something worth keeping in mind. It might, for example, help us not be so fearful of bacteria. They’re not necessarily bad for us. For one thing, they help us with digestion. More surprisingly, some scientists believe that, before people began frequent applications of soap and shampoo, one kind of bacteria (Nitrosomonas eutropha) flourished on people’s skin, acting as a “built-in cleanser, deodorant, anti-inflammatory and immune booster by feeding on the ammonia in our sweat and converting it into nitrite and nitric oxide”.

That’s the theory behind an article in the New York Times by a woman who went one month without using soap or shampoo. Aside from her greasy hair, she didn’t notice any ill effects. Nobody complained about her odor. In fact, after encouraging the growth of N. eutropha on her body for a month, her skin was in better shape than when she started the experiment. The scientists involved hope that bacteria might one day be used to treat various skin conditions, like eczema and acne, and even help certain wounds heal more quickly.

That’s the good news. The bad news (which is much worse than the other news is good), is that medical authorities are calling attention yet again to the spread of dangerous antibiotic-resistant bacteria. The Guardian reports that a group of senior British scientists expressed concern last week that we face “the prospect of people dying from routine infections because effective antibiotics no longer exist”. One scientist said:

In the near future it is possible that a scratch from a rose thorn could become septic. Without effective antibiotics, septicaemia could easily set in and result in death. It is a terrible prospect, but a very real one. We are facing a return to the state of affairs that existed before antibiotics were discovered.

Any kind of surgery and treatments that affect the immune system could all become life-threatening. As a stop-gap measure, the scientists recommend that hospitals go back to having old-fashioned rooms with widely-separated beds and windows that can be opened to allow in fresh air. 

lewes_victoria_hospital_ward

Unfortunately for us communities of cells and bacteria, the drug companies aren’t developing new antibiotics, because there is little profit to be made off drugs that people only take for a short period of time. Chalk another one up for capitalism and the free market. 

As dangerous bacteria continue to evolve, it becomes increasingly likely that epidemics will sweep the world before new antibiotics or other treatments will be available, unless there is increased government support for the needed research. The alternative is to wait for the problem to get so bad that it becomes profitable to fix it. 

Taking these developments into account, it’s safe to assume that one day many of us will be dead from bacterial diseases we don’t know how to fight. But our skin will be in the best shape ever.

Some Spiders Like Group Homes Too

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Scientists have identified about 43,000 species of spiders in the world. Only about 25 of these species are social animals, living in communities like ants and people.

One such species lives in Africa. A group containing from 20 to 300 spiders called Stegodyphus mimosarum weave large communal webs like this:

web1a

What is especially interesting about these little spiders is that the longer they live together, the more specialized they become.

Spiders seem to have personalities of a kind. Some are more shy than others; some are more aggressive. Researchers have discovered that if they put together a small group of these spiders, their individual traits gradually become stronger. The aggressive spiders, for example, become more aggressive.

As their colonies grow, the spiders also take on specialized social roles that seem to depend on their personalities, the shy ones staying inside the web and tending to the young, while the more adventurous ones defend the web and subdue prey (usually insects, but not always). Which roles individual spiders take on also appears to depend on the needs of the colony.

According to the New York Times:

The researchers view the development of strong personalities as the behavioral version of so-called niche partitioning, carving out a specialty in a crowded, competitive world….[One researcher] says the spider work neatly illustrates the mix of plasticity and predilection that underlies personality.

“I think it’s such an appealing idea that social interactions could cause social niches, and it resonates with our own experience as humans,” she said. “When you go into a group, your behavior changes depending on the nature of that group, but it can only change so far.”

It’s remarkable that these tiny spiders, with their even tinier brains, not only react differently to various stimuli but form communities that increase in size as individuals gravitate toward specific social roles, depending on their own proclivities and the needs of the community. Since that sounds a lot like what it takes to grow up and make a living in New Jersey, it’s one more piece of evidence that we too are part of nature and not as uniquely talented as we think we are. 

And the Lion Shall Lie Down With the Lamb

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Even in this universe, it was probably going to happen sooner or later: our first cat video here at WOCS. My shaky justification is that it’s interesting from a scientific perspective (compare Konrad Lorenz famously showing young geese imprinting on the first moving stimulus they observed, for example, Lorenz’s boots or a toy train). 

Plus, it’s a nice way to spend five and a half minutes:

Historical and literary note: Isaiah 11:6-7 doesn’t actually refer to the lion lying down with the lamb (or the cat lying down with the ducklings):

The wolf shall dwell with the lamb, and the leopard shall lie down with the kid, and the calf and the lion and the fatling [young animal fattened for slaughter] together, and a little child shall lead them. The cow and the bear shall feed; their young shall lie down together; and the lion shall eat straw like the ox.

And while we’re quoting scripture, let’s not forget Ezekiel 16:49:

Behold, this was the guilt of your sister Sodom; she and her daughters had pride, surfeit of food, and prosperous ease, but did not aid the poor and needy. 

Got that, Congressman Ryan?

Clearing Up This Multiple Universe Thing (Maybe)

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I haven’t been blogging much lately. It’s not that I have anything against blogging – I haven’t been doing much of anything lately, unless breathing and digesting count.

In another universe, however, I’ve been blogging up a storm while hiking through Alabama with Gwyneth Paltrow and Vladimir Putin. That’s what many physicists seem to believe anyway. (In that other universe, Vlad promised Gwyn and me that he’s going to stop interfering with Ukraine.) 

For example, Max Tegmark of M.I.T. has written a book that, according to the New York Times, suggests that he was almost hit by a truck while riding his bike in Stockholm, and the truck hit him, resulting in some slight injuries, and the truck really clobbered him, which meant he didn’t live to write the book he later wrote: 

He endured every possible outcome, happy and unhappy, that can befall a bicyclist who encounters a speeding truck. All of these happened, he argues, because everything that can happen does happen — in at least one of an infinite number of universes.

This extremely large set of parallel universes is called the “multiverse”. Our universe, the particular one that I’m experiencing now, in which I’m not pals with Gwyn and Vlad, is merely one universe among many – no more real than the others. 

Very smart people like Max Tegmark and Stephen Hawking accept the multiverse theory, which is also known as the “many-worlds interpretation of quantum mechanics”. They think this apparently crazy idea best explains the truly crazy stuff that happens at the quantum level of reality, like the double-slit experiment and the situation with Schrödinger’s cat. We’ll probably never know for sure, since verifying the existence of another universe is supposed to be impossible.   

Still, something has been bothering me since I read that article in the Times. When people talk about parallel universes, they usually talk about universes branching off from each other. What supposedly happens is that whenever there’s more than one possibility in a given universe, that universe somehow splits into two or more separate universes. You start out in one universe and get hit by a truck but in another universe you escape injury. In one universe, you order pork chops, in another you have a salad and in a third you go somewhere else to eat. The examples in these discussions are almost always familiar events or decisions, the kind of possibilities we can all relate to.

Physicists, however, don’t usually concern themselves with what people have for dinner. Quantum physics, in particular, concentrates on very small-scale events. Will an atom of carbon-14 decay or not? How frequently do quantum fluctuations (the so-called “appearance and disappearance of virtual particles”) occur? In theory, each of these small-scale, apparently random quantum events marks a divergence in the history of the universe. If an atom decays, the universe goes one way. If it doesn’t decay, the universe goes another way. According to the many-worlds theory, as it’s almost always explained, each event that could have happened differently results in the creation of separate universes.

Of course, since the universe is a very big place, there is room for lots of events to occur, especially the tiny, random ones. Here’s a quote from The Many-Worlds Interpretation of Quantum Mechanics by the physicist Bryce DeWitt: 

This universe is constantly splitting into a stupendous number of branches, all resulting from the measurement-like interactions between its myriads of components. Moreover, every quantum transition taking place on every star, in every galaxy, in every corner of the universe is splitting our local world into myriads of copies of itself [161].

Wow! Is it really possible that equally gigantic, almost exact replicas of the universe, with all its particles, planets, galaxies and so on, are springing into existence zillions of times a second, whenever a sub-atomic particle somewhere in the universe sneezes? And that those replicas immediately start replicating themselves? As that old TV commercial said, that’s one spicy meatball!

The effect seem way, way, way out of proportion to the cause. Where does all the energy come from to create fully-formed copies of previously existing universes? Assuming that these new universes immediately pop into existence, how do they get so big and so detailed so quickly? Or maybe universe creation takes a long “time”, but we don’t notice any breaks in the action because we keep coming into existence with our memories and instrument readings intact, as if nothing weird has happened (remember that you and I have lived through zillions of such universe creations – it’s not as if we’ve always lived in the nice, stable universe and everybody else is off living in copies).

I don’t know enough math or physics to criticize the many-worlds theory for real, but I was pleased to see that one of the things bothering me is a standard objection to the theory. From Wikipedia:

Conservation of energy is grossly violated if at every instant near-infinite amounts of new matter are generated to create the new universes.

To which, proponents of the theory are said to have two responses:

First, the law of conservation of energy says that energy is conserved within each universe. Hence, even if “new matter” were being generated to create new universes, this would not violate conservation of energy. (That doesn’t seem like a very good answer to me, since it amounts to saying, “It’s very strange that there’s an exception to this fundamental law, but that’s what happens”.)

Second, conservation of energy is not violated since the energy of each branch has to be weighted by its probability, according to the standard formula for the conservation of energy in quantum theory. This results in the total energy of the multiverse being conserved. (Which seems to mean that if there’s a 50/50 chance of some atom decaying, each new universe has half as much energy as the last one. Wouldn’t that eventually result in new universes having no energy at all?)

So it was with some relief that I turned to a helpful website called “Ask a Mathematician”. It should really be called “Ask a Mathematician or Physicist”. because it’s apparently a mathematician and a physicist answering questions, most of which have to do with physics (they don’t identify themselves, they just answer questions). A few years ago, they got this question:

According to the Many Worlds Interpretation, every event creates new universes. Where does the energy and matter for the new universes come from?

Here’s some of the physicist’s (rearranged) answer:

If you go online (or read some kind of book or something), you generally find the Many Worlds Interpretation presented as the universe “splitting”. Something along the lines of “everything that can happen will, just in different universes”. Supposedly, every time any kind of quantum event happens that could have one of several results (which is essentially every moment for every thing, which is plenty) the entire freaking universe splits into many universes. But, the universe contains a lot of energy….So, whence does this energy come?

[However,] there is no new energy or matter (or even new universes)…The universe doesn’t split or spawn new universes…. The universe doesn’t branch so much as it meanders and intertwines….If you want a picture to work with, rather than thinking about the universe as an ever-branching tree, think of it as an intertwining (albeit, very complex) rope.

The many (like: many, many) different versions of the universe branch apart, and come together all over the place. That is: one event can certainly lead to several outcomes, but in the same way, several causes can lead to the same event.  Everything that could happen will happen (given the present) and everything that could have happened did happen (given the present)….

A particle comes along with some amount of energy. When it has a choice of two paths it takes both.  The energy of the particle is divided in proportion to the probability of the path taken.  So, for example, a 50% chance of each path means equal division of the energy and matter of the particle.  Before the fork all of the energy is on one path, and afterwards, despite the fact that the particle is behaving as though it’s in two places, the same amount of energy is present, just spread out.

So, while it’s fun to talk about “other quantum realities” and “different universes”, it’s more accurate to say that everything is happening in one universe. One, stunningly complex, weirdly put together, entirely counter-intuitive universe.

Clear? Despite the standard explanation, we’re all living in the same universe, but it’s a universe that has lots of its contents in strange, probabilistic quantum states. Since these various states (like when a photon is 50% likely to be here and 50% likely to be there) are equally real, they can be thought of as parts of different universes, but that’s just a manner of speaking.

Whether or not this way of understanding the multiple universe theory is correct (is it, since Max Tegmark apparently suggests otherwise?), it makes me feel better. For one thing, it’s less mind-boggling. Big branching universes seem both implausible and terribly wasteful. Secondly, I think there’s zero probability that one of me is hiking through Alabama with Gwyneth and Vladimir (while wearing a blue shirt, and a red shirt, and a green shirt, and no shirt, etc. etc.) while also breathing and digesting here in the Garden State.

(Note, however, that if the universe is infinite in time and space and configured a certain way, it’s possible, maybe even a sure thing, that everything that isn’t contradictory happens over and over again. But that’s something to wonder about another day.)