Tag Archives: Technology

Fusion power: The tritium problem

In my previous post on fusion power, I discussed how fusion power will not be possible on Earth without using tritium. I then discussed how Tritium is exceptionally *rare* on Earth (the entire planet has only enough Tritium to power Chicago for a month or so). Now I will discuss why it won’t be possible to make enough Tritium to solve this pressing issue with fusion power. Thus I hope to answer the question posed in my first post: fusion power is hopeless (within my lifetime at least).

The 25kg of Tritium produced by Canada’s CANDU fission reactors represents the sum total of all the tritium here on Earth. If fusion advocates want to have enough Tritium to start up loads of fusion power plants, they’ll need a lot more than that.

The first method may be to just produce more tritium the way Canada does. The CANDU reactors use heavy water (water with the hydrogen-1 atoms replaced with hydrogen-2 aka deuterium) to moderate free neutrons and cool the system. When the deuterium in the water interacts with a neutron, it may capture it and transform into tritium (aka hydrogen-3). This tritium is highly radioactive with a half-life of just 12ish years, so Canada separates it out and stores it in shielded containers.

To get a tiny bit more technical: a single atom of uranium-235 undergoes fission and releases either 2 or 3 neutrons (average 2.5). 1 neutron is needed to keep the fission reaction going, 1 neutron can hit deuterium and transform it into tritium, and we can estimate that the remaining 0.5 neutrons will be lost due to hitting some other atom in the area that isn’t deuterium or uranium.

But now we have a process to create tritium, so can’t we just scale it up? Unfortunately no, this is unfeasible. Remember that it takes 1 atom of uranium (which weighs 235 atomic units) to create 1 unit of tritium (which weighs 3 atomic units). 235 ÷ 3 is about 78, so it takes 78 kilograms of ultra-enriched uranium to produce a single kilogram of tritium. The CANDU reactors themselves don’t even use highly enriched uranium, their uranium contains only about 1% U-235, so for them it takes 780 kg of uranium for each 1 kg of tritium they produce.

Even if we could ensure that extra 0.5 neutrons wasn’t lost, that doesn’t get us very far. And to be honest, even this math undersells the problem. That 780 kg of uranium to produce 1 kg of tritium *only works if we extract every single possible neutron from the fissile uranium*. In practice, the nature of half-lives means that the uranium produces most of its neutrons quite early and then neutron production quickly decreases, to the point that it’s producing too few neutrons to reliably continue a chain reaction. The actual CANDU reactors replace their uranium regularly to maintain a high enough level of neutrons, and they use about 100,000 kg of uranium to produce about 0.1 kg of tritium each year. That is just too much uranium (all of which needs significant work to keep it safe and secure) to feasibly scale this process up to produce lots and lots of tritium.

Sure there are other neutron source, and other targets for producing tritium. But the math is still the same. You need an extraordinary amount of some very heavy element (the kind that undergoes fission) to create a tiny amount of a very light element (tritium). Those heavy, fissionable elements are very dangerous and pose potential national security threats, so must be treated with high levels of security. The tritium is *also* dangerous, but has the added problem of requiring extra steps to separate it from the heavy-water mix that it’s a part of. Producing tritium with fission is a dead end if we want enough of it for fusion.

But of course no one wants to produce tritium using fission, they want to produce tritium using *fusion*, and here’s where our problem goes from bad to worse.

Most tritium-fusion advocates have a clear picture in their mind of how it will work:

  • Tritium and deuterium will fuse in a reactor, and this fusion will produce neutrons
  • The reactor will be surrounded by a blanket of (usually) lithium
  • The lithium will absorb a neutron and undergo fission, creating a new unit of tritium
  • That tritium will be fed back into the fusion process, continuing the cycle indefinitely

It all seems to simple, but every single step of this has problems, and no one has yet even demonstrated a coherent *plan*, let alone demonstrated a practical *system* for creating and extracting tritium in this way. It’s akin to saying “fusion is easy, just get the atoms close together” without having any plan for how to do that.

First, the high energy neutron created during fusion carries 80% of the reactions heat energy. That means it can’t just be used to create new tritium, if we want this reactor to actually be a *power plant*, we need that neutron to also boil water and drive a steam turbine. That means 1 neutron per fusion reaction isn’t enough.

So we add elements to the lithium blanket that “breed” more neutrons. These elements, when hit by a neutron, create 2 or more neutrons in turn. Great, now we can turn 1 neutron into as many as we want, with some of those neutrons being allowed to produce heat for our steam turbine, and the others creating tritium to go back into the reaction. Mission solved, right?

But this creates our first fundamental problem with the blanket. We have a blanket of solid lithium, plus beryllium and/or lead to act as neutron multipliers, and that blanket is constantly being destroyed by neutrons *as a necessary step to produce more tritium*.

This blanket isn’t *just* there for making neutrons mind you, it will also need to carry away the heat energy from those neutrons to be used to boil water. That means it will need all the steel piping, diagnostic sensors, and other components necessary to safely transfer heat away. That means the blanket needs a lot of non-lithium components in it, and those components *can also be destroyed by the fast neutrons*. Then again, as the lithium in the blanket is already expected to be destroyed by the fast neutrons, that can compromise the precise structural system needed for heat to be transferred and for diagnostic sensors to get an accurate reading. A single microscopic crack in the blanket could through the entire system into chaos, and a crack is inevitable when the whole point of the blanket is to be destroyed.

Not to mention the helium problem. A neutron can pass through a few atoms of lithium before it hits one to create tritium. That tritium can get locked within the structure of the wall and beta-decay into helium-3 before it can be extracted. Helium-3 can build up inside the walls of the reactor, and it aggregates together since it can’t bind to the steel or other elements that make up the wall. These cavities of helium-3 reduce the structural integrity of the whole system, as you suddenly have a section of wall sitting on top of gaseous helium instead of solid steel. This again is catastrophic to structural integrity, and it’s hard to make helium obey you at the best of times, even worse when it’s trapped inside a metal lattice. So it won’t be so easy to just remove the helium from the system.

But even if you magically create a wall that won’t be destroyed through neutron damage, and can breed enough new tritium to continue the reaction, there is no working proposal to extract that tritium and feed it back into the reactor. If the lithium blanket is a solid wall, then new tritium will be trapped inside that blanket, it cannot simply flow out straight through a solid wall. You might try to inject helium purge gas, to purge out all the trapped tritium, but now you have a different problem.

Those high energy neutrons are dumping enormous amounts of heat into this wall as well, there will be violent thermocycling as the walls heat with neutron radiation and are then desperately cooled back down by heat exchange (this heat is needed, remember, to boil the water for the steam turbine). The areas of the wall containing lithium will be crushed or sintered together, blocking any helium from removing the trapped tritium within.

Finally, a solid wall of steel and lithium with have thermal conductivity that is unpredictable and well-nigh impossible to model. The elements will touch as microscopic points, and those points will again move around as the wall expands and contracts from thermal forces. So you won’t have a wall that heats evenly and can be cooled evenly. Some patches will hit thousands of degrees and can warp or melt the wall if they aren’t cooled down fast enough.

So then maybe a solid wall won’t work for us, but how about a liquid wall? Lithium and our neutron multiplier atoms can be heated to hundreds of degrees until they liquify. Then we can surely have a homogenous liquid that heats and cools evenly, where helium cannot get trapped in solid lattices, and we can pass this liquid over chemical filters to extract all of the precious tritium from within. Simple right?

But this is even less probable of a solution. A river of molten lithium is highly conductive, and as it needs to be pumped through and around the high powered magnetic fields of the fusion reactor, it will trigger an unbelievable electromagnetic braking force. Remember the “braking radiation” I discussed in the previous post? We aren’t done with electromagnetics ruining our nuclear party. The conductive liquid metal passing through the magnetic fields will create a massive *secondary* magnetic field that acts to oppose the moving conductive fluid that created it. So our river of molten lithium will suddenly create a powerful force pushing it in the *opposite direction* that we need it to go in, forcing an ungodly amount of pumping power to be spent just to force it to move the correct way.

Then there’s the fact that a river of molten lithium will be highly corrosive, trying to tear down whatever piping infrastructure we’re using to pump it.

And finally, we still aren’t done with tritium problems. Yes it’s easier to remove tritium from a river of molten lithium than a lattice of solid lithium, but we still have a problem. Tritium diffuses through solid metals at high temperatures, meaning it will quickly leak out of our molten lithium, through the plumbing, and into any water we’re using as a coolant for this whole nightmare of a system (remember, we still NEED water coolant to drive our steam turbine if this thing will make any power!). This doesn’t just steal the tritium we need to continue the reaction, it produces tritiated water, highly radioactive and a severe biological safety hazard.

So no, we can’t *just make more tritium* to run our fusion power plants. We can’t just scale up our systems for creating tritium from fission. And any proposal to make tritium from the fusion itself is still an entirely separate unsolved problem, *on top of the unsolved problem of making fusion power in the first place*. The tritium created will try its level best to destroy whatever wall or plumbing infrastructure we use to create it. It will decay into helium-3, which will try even harder to do the same. And the wall itself is an unsolved problem of heat exchange, hydrodynamic forces, gas exchange, and structural integrity, all of which has to be *perfect* so that enough tritium is secured to continue the reaction.

And sure, you can lose a few atoms of tritium here and there, but any lost tritium will have to be repaid by redirecting more of the fusion reactor’s neutrons towards tritium and using fewer neutrons to create actually electrical power. You know, *the actual point of a nuclear reactor*. Even getting a positive production of tritium is an untested problem, *without* trying to create any nuclear power whatsoever.

There are some things that work great in a lab bench but just don’t work when scaled up. This is exactly the problem that sank Amyris, a biotech company I blogged about long ago. They had a good foundation of synthetic biology, and they thought they could easily scale up from a benchtop setting that made micrograms of product to a factory setting making the kilograms needed for industrial use. They just couldn’t do it, and they filed for chapter 11 bankruptcy in 2023. It’s not that what they wanted to do is impossible, it’s that it is difficult, expensive, and there are cheaper options available.

That, I think, is what will ultimately sink nuclear fusion for the remainder of my lifetime, not that it’s impossible, that it just isn’t worth it. Any problem humanity faces might be theoretically possible, we could redirect the entire National Science Foundation funding to making better AIs for Civ VI, for example, and we’d certainly get something better than what Firaxis gave us. But is that value for money, compared to everything else the NSF funds? No.

And so, is fusion power possible? If you feed the entire budget of the NSF into it, maybe. But even if we can heat our homes by burning money, that doesn’t make it a good investment. The NSF and other agencies want to fund areas of research that will create their own positive return on investment, that will enter a virtuous cycle where profits from the technology get reinvested into improving the technology further.

The NSF’s investment into genetic engineering did exactly that. In the 1970s, at the same time fusion was being funded and nuclear fission wasn’t yet politically toxic, the NSF was giving tiny amounts of funding to biologists and chemists to study genetics. To find out how we can read and use genes to our advantage. But unlike fusion power, genetics entered a *virtuous cycle*, where their projects were so successful they could start profitable companies with them, and those profitable companies then reinvested back into genetics technology. The human genome project was completed around the year 2000, and in 1970 knowing the entire genome of an individual would have seemed like *more* of a pipedream then getting power out of nuclear fusion (we already had nuclear fission, remember!).

But fusion never entered a virtuous cycle. There were never fusion successes that could go on and make profits to reinvest. And *that* is why fusion was abandoned, not because of some evil conspiracy, but because of simple failure.

Failure which I believe will continue. Because still today, investing in fusion just isn’t worth it. We can get power in a dozen of other ways, so long as we don’t have NIMBYs blocking every solar array or gas turbine needed to power our modern society. And don’t forget that fusion will have to face those same NIMBYs, you can’t compare a theoretical fusion plant to a currently built gas or solar plant. You have to include the NIMBY factor of convincing the same people who think 5G is giving them cancer that fusion power *won’t* give them cancer. Or the same people who don’t want a new apartment because it’s *ugly* that a fusion plant *won’t* be ugly.

The technological limitations of nuclear fusion power are still unsolved. They are solvable but solving them isn’t worth the amount of money needed considering the extreme amount of known unknown and even unknown unknowns. We don’t know how to do it, and we’re better off spending our money on things we do know.

Sure, let the NSF keep funding the national ignition lab, you can even keep funding ITER if you think it will help. But startups like Commonwealth Energy aren’t going to provide power to the grid within my lifetime, and it isn’t worth spending our entire GDP to solve these problems sooner than that.

Opportunity Costs in Civilization 6

One of the most important concepts I learned in economics is the idea of opportunity costs.  Every action we take has a cost, not just the cost of the action itself, but the cost of *now not being able to do something else* with either the time or money or both that we just spent.  

A simple example: a company only has 100$ to invest in a machine.  If they buy the machine that makes blue widgets, they can’t also buy the machine that makes red widgets.  Thus, buying the blue widget machine doesn’t *just* cost 100$, it also has the *opportunity cost* of not buying the red widget machine.

There are also opportunity costs with time, if you decide to go to Europe for your holiday vacation, you can’t also go to South America at the same time.  So the cost of going to Europe isn’t just the cost of the time and the tickets, it’s also the opportunity cost of not going to South America (or anywhere else) as well.

As an aside, this is why for some people it can make sense to NOT go to college EVEN IF college were totally free.  The cost of going to college includes the *opportunity cost* of not having a full-time job (if you’re a full-time student).  

A comedian once made a joke that, after graduating college he couldn’t find any work “because the dropouts already had the jobs.”  A funny joke, but it demonstrates a point:  You spend 4 years getting a degree, but if that degree doesn’t measurably increase your employment prospects, you could have been better off spending those 4 years getting work experience at a full-time job.  You could not only get the money that a full time job gives you, but the experience itself would increase your employability and ability to get better jobs.

So the education and degree you’re seeking needs to increase your employability *more* than just doing 4 years of work.  If not, then it’s a net loss *even if your education was free* because you had the *opportunity cost* of not getting those 4 years of work experience.

But I didn’t want to blog about college, I wanted to blog about Civilization again.

The non-gamers in my audience may be tired of my gaming blogging, but I’ve spent a lot of this holiday season playing Civ IV and Civ VI with friends, so I’ve been thinking about this.

I complain that in Civ VI, some of the leaders seem to have traits that are utterly worthless, they don’t feel like they improve your Civ’s abilities any more than having a vanilla Civ with *no* traits.  Eleanor of Aquitaine is one of these, her ability to culture-flip cities feels very underpowered and completely useless, and doesn’t make her any more powerful than a Civ that doesn’t have any abilities at all.

My friend shoots back at this by saying that if you put a lot of resources into it, you can set up a situation in which you culture-flip whole continents in an instant.  And yes, this is theoretically possible.  Does that mean Eleanor is “very powerful in the right circumstances?”  No.  Because of *opportunity costs*.  

See, the cost of putting all your resources into Eleanor’s culture-flipping ability is that *you can’t put those resources into other things*.  You can’t research technologies or build military units if you are instead spending your entire GDP on culture buildings.  Culture isn’t free, and it doesn’t just cost what it costs to produce it, it has the *opportunity cost* of not doing anything else with that money and production.

So in any situation where Eleanor can “culture flip a continent” by spending an absurd amount of resources on culture, any other Civ could just use those resources to win the game with military, or science, or even diplomacy.  

Eleanor’s ability is useless not because you *can’t* use it to do things, but because the amount you have to spend to make her ability not-useless could instead be better used to win the game in *any other way at all*.  Her ability has an *opportunity cost* in that if you try to use it to its fullest, you are by definition not using those resources on better strategies that will win you the game more easily.

And that’s what I feel about a lot of the Civ VI leaders.   Some  leaders have abilities so minor they don’t feel impactful.  Some have abilities that completely change the nature of the game.  And some like Eleanor have these abilities that are actually traps, because the opportunity cost of trying to use their ability to its fullest makes you worse off than if you’d ignored their ability and played the game normally.

People didn’t like Civ IV’s leader system because every leader drew from a limited pot of abilities.  Gilgamesh is Creative/Protective, while Catherine the Great is Creative/Imperialistic.  From my perspective, that’s unique, *no one but Gilgamesh has that specific combination of traits*.  From other people’s perspective though “they’re both creative so they’re too similar to be cool.”  

These people who say this seem to really be drawn to Civ VI because every leader has *completely unique abilities* not seen anywhere else.  But from my perspective “many of those abilities are worse to use than just ignoring the ability and playing the game normally.”  Leaning into your “special ability” can have an opportunity cost, and no one but me seems to recognize this.

So in the future, please think about opportunity costs, both for college and for your video games.  Making a nation have a super special ability isn’t actually cool if leaning into that ability makes you worse off than if you’d ignored it and played the game normally.   Opportunity costs are real, even if not everyone understands them.

The Great Disruption: A Degrowth Apocalypse

In 1972, a report on “the limits to growth” was published laying out a detailed argument that there simply weren’t enough resources in the world for economies to continue growing.  In 2008, the fruits of that 1972 paper came to pass, as every grifter who’d read it published a book saying that the financial crisis was proof that economic growth was now at an end.  Richard Heinberg said this in 2010, and in 2011 Paul Gilding did the same.

In a blurb, “The Great Disruption” by Paul Gilding is just like “The End of Growth” By Richard Heinberg, which I reviewed previously.  The two books both claim that resources, *especially fossil fuels* are running out (or rather, ran out back in 2010-2011 when these books were published).  Both books claim that the 2008 financial crisis was caused by this resource constraint (and *not* by the sub-prime mortgage crisis which actually caused it).  And both claim that since we’ve reached the limits of growth (back in 2010…) we now have to live in a world where no more growth is possible.  We instead need to adopt Degrowth, where we eliminate fossil fuels entirely and shrink out economies and our livelihoods in order to continue living on this earth.

But unlike “The End of Growth,” this book is much more than a thesis, it’s a sermon.  In my opinion, “The Great Disruption” is Paul Gilding’s stab at writing a Degrowther Book of Daniel.  

For those of you who aren’t faithful, the Book of Daniel is one of the primary “apocalypse” books of the old testament.  An apocalypse doesn’t really mean the “end of the world,” rather it literally means “revealing,” and an apocalypse book is when the truth of the future is revealed to a prophet and he writes that truth down for all to read.

In the Book of Daniel, Daniel foresees the rise and fall of several earthly empires, culminating in the rejuvenation of Israel and the eternal reign of God.  It doesn’t matter, says Daniel, that the current world is ruled by tyrants and that the situation seems hopeless.  God will destroy the evil and restore the righteous, and it *will* happen just as Daniel says it will.

In “The Great Disruption,” Paul Gilding foresees the inevitable fall of capitalism and the liberal world order, culminating in a degrowther paradise where we all agree to consume at little resources as possible to maintain the world’s stability.  It doesn’t matter, says Gilding, that the current world is ruled by capitalism and the situation seems impossible.  “We have no other choice” he says, and so everything he says *will* happen, just as he says it will.

This comparison to scripture isn’t an idle one.  The whole time I read “The Great Disruption” I kept noting how it felt like a sermon, not a argument.  Paul Gilding doesn’t really try to persuade the reader that his plan for a degrowth future is the best one, instead he repeatedly asserts that “we have no other choice” and that everyone *will eventually accept* that “we have no other choice.”  And so, once Government, Corporations, and People eventually accept that we “we have no other choice,” they will all begin acting exactly as he thinks they should act, by cutting off fossil fuels, travel, and all consumer goods in order to degrow the economy.

He tries to persuade the reader of some things, yes.  He works to persuade us that climate change needs to be addressed, that there are limits to growth, and that the 2008 financial crisis was the moment when Growth Finally Stopped for all time.  

But he doesn’t ever try to persuade the readers that his degrowth future is possible, feasible, or better than the other options.  He doesn’t even try to persuade us that it will actually happen.  He keeps writing anecdotes about people questioning the possibility and feasibility of his plans and predictions, and he keeps responding the same way: “we have no other choice.”

This is the hallmark of a sermon, or an apocalypse.  In such works as these, The Truth (capital Ts) isn’t something you argue or persuade, but something you announce and reveal, with no room for questioning or doubt.  Any quibbles about the details are brushed aside because “it will happen, don’t question it.”  Instead, the focus is on laying out this revealed future, what will it look like, who will be punished, and who will be rewarded.

I’ll try to write more on Paul Gilding’s book, but I can’t recommend it as anything other that a hoop to be dunked on.  Paul’s predictions and prognostications are all wildly off-base, he doesn’t understand economics *or* energy, and everything he said Will Happen simply Hasn’t.  He wanted to impart a moral imperative into the Degrowth movement, with a vision of the future that was as utopian as it was unquestioned.  But his predictions for the future have all been disproven by our present, and he looks as mad as the Malthusians who believed we’d run out of food in the 19th century.

Overall this book is what I’ve come to expect from degrowthers.  Every single prediction of theirs has been disproven, yet they keep pretending that history is on their side.  I don’t know if they’ll ever learn. But their books give me something to dunk on.

So just how *do* you get good at teaching?

As a scientist with dreams of becoming a professor, I know teaching is part of the package. Whether it’s a class of undergraduates or a single student in a lab, your knowledge isn’t worth anything if you cannot teach it to others. I always say: no one would have cared about Einstein if he couldn’t accurately explain his theories. It doesn’t matter how right you are, science demands you explain your reasoning, and if you can’t explain in such a way to convince others, you still have a ways to go as a scientist.

Einstein was a teacher. After discovering the Theory of Relativity, he wrote and lectured so as to teach his theory to everyone. Likewise I must be a teacher, whether teaching basic concepts to a class of dozens, or teaching high-level concepts to an individual or a small group, teaching is part of science, and mandatory for a professor.

But how do I get good at it?

The first problem is public speaking. I don’t think I get nervous speaking in public, but I do have a tendency to go too fast, such that my words don’t articulate what I’m actually thinking. It’s hard to realize that the concepts you know in your head will be new and novel to the whole world that lives *outside* your head. When teaching these concepts to someone else, you need to go step by step so that they understand the logical progression, you can’t just make a logical leap because you already know the intervening steps.

So OK, I need to practice speaking more, but beside that, what’s the best method for teaching? And here we get to the heart of why I’m writing this post, *I don’t know and I don’t think anyone does*.

Every decade it seems sociologists find One Weird Trick to make students learn, and every decade it seems that trick is still leaving many students behind. When I went to school, teaching was someone standing at the front of the class, giving a lecture, after which students would go home and do practice problems. This “classic” style of teaching is now seen as passe at best, outright harmful at worst, and while it’s still the norm it’s actively shunned by most newer teachers.

Instead, teachers now have a battery of One Weird Tricks to get students to *really* learn. “ACTIVE learning” is the word of the day, the teacher shouldn’t just lecture but should involve the students in the learning process.

For instance, the students could each hold remote controls (clickers) with the numbers 1 through 4 on them. Then the teacher will put up a multiple-choice question at random points during class, and the students will use their clicker to give the answer they think is correct. There’s no grade for this except participation, and the students’ answers are anonymized, but the teacher will give the correct answer after all the students answer, and a pie chart will show the students how most of their classmates answered. So the theory is that this will massively improve student learning in the following ways:

  • Students will have a low-stakes way to test their knowledge and see if they’re right or wrong, rather than the high-stakes tests and homework that they’re graded on. They may be more willing to approach the problem with an open mind, rather than being stressed about how it will affect their grade.
  • The teacher will know what concepts the students are having trouble on, and can give more time to those prior to the test.
  • Students stay more engaged in class, rather than falling asleep, and likewise teachers feel more validated with an attentive class

The only problem is that the use of clickers has been studied, and has failed to improve student outcomes. Massive studies and meta-analyses with dozens of classes, thousands of students, and clickers don’t improve student’s learning at all over boring old lectures.

Ok, how about this One Weird Trick: “flipped classrooms.” The idea is that normally the teacher lectures in class and the students do practice problems at home. What if instead the students’ homework is to watch the lecture as a video, then in class students work on problems and the teacher goes around giving them immediate and personalized feedback on what they’re doing right or wrong?

In theory this again keeps students far more active, they’re less likely to sleep through class and the immediate feedback they receive while working through the problem sets helps the teachers and students know what they need to work more on. Even better, this One Weird Trick was claimed to narrow the achievement gap in STEM classes.

But another large meta-analysis showed that flipped classrooms *again* don’t improve student learning, and in fact *widen* the achievement gap between minority and white students. Not at all what we wanted!

In theory, science teaches us the way to find the truth. Our methods of storing information have gotten better and better and better as we’ve used science to improve data handling, data acquisition, and data transmission. I read both of those meta-analyses on my phone, whereas even just 30 years ago I would have had to physically go to a University Library and check out one of their (limited) physical journals if I wanted to read the articles and learn if Active Learning is even worth it or not.

But while we’ve gotten so much better at storing information, have we gotten any better at teaching it? We’ve come up with One Weird Trick after One Weird Trick, and yet the most successful (and common) form of teaching is a single person standing in front of 20-30 students, just talking their ears off. A style of teaching not too far removed from Plato and Aristotle, more than 2,000 years ago.

I want to get better at teaching, and I think public speaking is part of that. But beyond just speaking gooder, does anyone even know what good teaching *is*?

Gene drives and gingivitis bacteria

One piece of sci-fi technology that doesn’t get much talk these days is gene drives. When I was an up and coming biology student, these were the subject of every seminar, the case study of every class, and they were going to eliminate malaria worldwide.

Now though, you hardly hear a peep about them. And I don’t think, like some of my peers, that this is because anti-technology forces have cowed scientists and policy-makers into silence. I don’t see any evidence that gene drives are quietly succeeding in every test, or that they are being held back by Greenpeace or other anti-GMO groups.

I just think gene drives haven’t lived up to the hype.

Let me step back a bit: what *is* a gene drive? A gene drive is a way to manipulate the genes of an entire species. If you modify the genes of a single organism, when it reproduces only at most 50% of its progeny will have whatever modification you give it. Unless your modification confers a lot of evolutionary fitness to the organism, there is no way to make every one of the organism’s descendants have your modification.

But a gene drive can do just that. In fact, a gene drive can confer an evolutionary disadvantage to an organism, and you can still guarantee all of the organism’s decedents will have that gene. The biggest use-case for gene drives is mosquitoes. You can give mosquitoes a gene that prevents them from sucking human blood, but since this confers an evolutionary disadvantage, your gene won’t last many generations before evolution weeds it out.

But if you put your gene in a gene drive, you can in theory release a population of mosquitoes carrying this gene and ensure all of their decedents have the gene and thus won’t attack humans. In a few generations, a significant fraction of all mosquitoes will have this gene, thus preventing mosquito bites as well as a whole host of diseases mosquitoes bring.

Now this is a lot of genetic “playing God,” and I’m sure Greenpeace isn’t happy about it. But environmentalist backlash has never managed to stamp out 100% of genetic technology. CRISPR therapies and organisms are on the rise, GMO crops are still planted worldwide, environmentalists may hold back progress but they cannot stop it.

But talk about gene drives *has* slowed considerably and I think it’s because they just don’t work as advertised.

See, to be effective a gene drive requires an evolutionary contradiction: it must reduce an organism fitness but still be passed on to the progeny. Mosquitoes don’t just bite humans for fun, we are some of the most common large mammals in the world, and our blood is rich in nutrients. For mosquitoes, biting us is a necessity for life. So if you create a gene drive that knocks out this necessity, you are making the mosquitoes who carry your gene drive less evolutionarily fit.

And gene drives are not perfect. The gene they carry can mutate, and even if redundancy is built in, that only means more mutations will be necessary to overcome the gene drive. You can make it more and more improbable that mutations will occur, but you cannot prevent them forever. So when you introduce a gene drive, hoping that all the progeny will carry this gene that prevents mosquitoes biting humans, eventually one lucky mosquito will be born that is resistant to the gene drive’s effects. It will have an evolutionary advantage because it *will* bite humans, and so like antibiotic resistant bacteria, it will grow and multiply as the mosquitoes who still carry the gene drive are outcompeted and die off.

Antibiotics did not rid the world of bacteria, and gene drives cannot rid the world of mosquitoes. Evolution is not so easily overcome.

I tell this story in part to tell you another story. Social media was abuzz recently thanks to a guerilla marketing campaign for a bacteria that is supposed to cure tooth decay. The science can be read about here, but I was first alerted to this campaign by stories of an influencer who would supposedly receive the bacteria herself and then pledged to pass it on to others by kissing them. Bacteria can indeed be passed by kissing, by the way.

But like gene drives, this bacteria doesn’t seem to be workable in the context of evolution. Tooth decay happens because certain bacteria colonize our mouth and produce acidic byproducts which break down our enamel. Like mosquitoes, they do not do this just for fun. The bacteria do this because it is the most efficient way to get rid of their waste.

The genetically modified bacteria was supposed to not produce any acidic byproducts, and so if you colonized someone’s mouth with this good bacteria instead of the bad bacteria, their enamel would never be broken down by the acid. But this good bacteria cannot just live in harmony and contentment, life is a war for resources and this good bacteria will be fighting with one hand tied behind its back.

Any time you come into contact with the bad bacteria, it will likely outcompete the good bacteria because it’s more efficient to just dispose of your waste haphazardly than it is to wrap it in a nice, non-acidic bundle first. Very quickly the good bacteria will die off and once again be replaced by bad bacteria.

So I’m quite certain this little marketing campaign will quietly die once its shown the bacteria doesn’t really do anything. And since I’ve read that there aren’t even any peer reviewed studies backing up this work, I’m even more certain of its swift demise.

Biology has brought us wonders, and we have indeed removed certain disease scourges from our world. Smallpox, rinderpest, and hopefully polio very soon, it is possible to remove pests from our world. But it takes a lot more work than simply releasing some mosquitoes or kissing someone with the right bacteria. And that’s because evolution is working against you every step of the way.

If the weavers get replaced by machines, who will buy the clothes?

I’ve seen way too many articles about AI casting doom and gloom that it will “replace millions of jobs” and that this will lead to societal destruction as the now job-less replacees have no more money to spend.  The common refrain is “when AIs replace the workers, who will buy the products?”

This is just another fundamental misunderstanding of AI and technology.  AI is a multiplier of human effort, and what once took 10 men now takes 1.  That doesn’t mean that 9 men will be homeless on the street because their jobs are “replaced.”  The gains reaped from productivity are reinvested back into the economy and new jobs are created.

When the loom replaced hand-spinning weavers, those weavers were replaced.  But they could eventually find new jobs in the factories that produced looms, and in other factories that were being developed.  When computers replaced human calculators, those calculators could now find jobs programming and producing computers.

For centuries now, millenia even, technology has multiplied human effort.  It used to take dozens of people to move a single rock, until several thousand years ago someone had the bright idea of using ropes, pullies, and wheels.  Then suddenly rocks could be moved easily.  But that just in turn meant the demand for moving rocks shot up to meet this newer, cheaper equilibrium, and great wonders like the Pyramids and Stonehenge were suddenly built.

The same will be true of AI.  AI will produce as many new jobs as it creates.  There will be people to produce the AI, people to train the AI, people to ensure the AI has guardrails and doesn’t do something that gets the company trending on Twitter.  And there will be ever more people to use the AI because demand is not stable and demand for products will rise to meet the increase in supply generated by the AI.  People will want more and more stuff and that will lead to more and more people using AI to produce it.

This is something that people get hung up on, they think that demand is stable.  So when something that multiplies human effort gets created, they assume that since the same amount of products can be produced with less effort, that everyone will get fired.  Except that demand is not stable, people have infinite wants and finite amounts of money. 

Technological progress creates higher paying jobs, subsistence farmers become factory workers, factory workers become skilled workers, skilled workers enter the knowledge economy of R&D.  These new higher paying jobs create people who want more stuff because they always want more stuff, and now have the money to pay for it.  This in turn increases demand, leading to more people being employed in the industry even though jobs are being “replaced” by machines.

To bring it all back to weavers, more people are working in the textile industry now than at any point in human history, even though we replaced weavers with looms long ago.

AI will certainly upend some jobs.  Some people will be unable or unwilling to find new jobs, and governments should work to support them with unemployment insurance and retraining programs.  But it will create so many new jobs as well.  People aren’t satisfied with how many video games they can purchase right now, how much they can go out to restaurants, how much housing they can purchase, etc.  People always want more, and as they move into higher paying jobs which use AI they will demand more.  That in turn will create demand for the jobs producing those things or training the AIs that produce those things. 

It has all happened before and it will happen again.  Every generation thinks that theirs is the most important time in the universe, that their problems are unique and that nothing will ever be the same.  Less than three years ago we had people thinking that “nothing will ever be the same” due to COVID, and yet in just 3 short years we’ve seen life mostly go back to normal.  A few changes on the margins, a little more work from home and a little more consciousness about staying home when sick, but life continued despite the once-a-century upheaval.

Life will also continue after AI.  AI will one day be studied alongside the plow, the loom, and the computer.  A labor-saving device that is an integral part of the economy, but didn’t lead to its downfall.