You are currently browsing the tag archive for the ‘science’ tag.

Here are the podcasts I’m tracking at the moment, with a link to a notable recent episode.

EconTalk – Lengthy interviews with experts on economics and social science. e.g. Acemoglu on Why Nations Fail

In Our Time – Panel discussions on random topics from history and science. e.g. Voltaire’s Candide

Planet Money – News coverage of economics that presents complex ideas quite simply. e.g. Cage Match: Coin Vs. Bill

Surprisingly Free – Interviews with experts on the internet and new technologies in general. e.g. Naomi Cahn on the digital afterlife

This American Life – Stories from Americans on random topics from current affairs to childhood memories. The best show of its kind. e.g. Retraction

More or Less – Entertaining investigations into numbers that appear in the media from Tim Harford. e.g. Austerity, border queues and bank holidays

Savage Love – Relationship and sex advice show. Equal parts entertaining, useful and disgusting. e.g. Savage Love Episode 287

While we are talking about  it, I also use BeyondPod to keep the episodes on my phone up to date! Podcasts are good for commuting and exercising, if you’re not yet hooked on them.

Two academics from my university think so:

Australian astronomers say finding planets outside the solar system that can sustain life should be made a top priority.

Dr Charley Lineweaver and PhD student Aditya Chopra from ANU have reviewed current research into environments where life is found on earth and the environments thought to exist on other planets.

They say understanding habitability and using that knowledge to locate the nearest habitable planet may be crucial for our survival as a species.

While I agree that in the long run space colonisation is central to humanity’s survival, this is not really sensible and is probably a misrepresentation of their research. We are far away from being able to establish self sustaining colonies on planets in our solar system let alone travelling to other star systems. By the time we have the technology to contemplate doing that we will long since have identified habitable planets without having gone out of our way to do so.

While space colonisation would help reduce the risk of human extinction the unfortunate reality is that the technologies that threaten to ruin us are going to come well before independent, robust and self-sustaining colonies are possible. Risky technologies like mind uploading or machine intelligence are probably prerequisites for colonising other star systems and maybe even long-term survival on Mars. Slowing the development of the most risky technologies, controlling their use, and developing safe havens on Earth itself are likely to be more cost effective strategies than space travel for the foreseeable future.

There are four possible effects a habit can have on someone’s preferences that I would like to distinguish. For convenience I have labelled them appreciation, satisfaction, dependency and addiction. For my purposes, appreciation is where you gradually achieve a higher level of welfare doing something the more that you do it. Likely examples would be meditation or watching a lengthy TV series. Satisfaction is where an activity leaves you sated, and therefore better off even if you stop doing it. Pleasant investments in yourself, such as studying something you enjoy, could be an example of this. Dependency is where the gain from doing a fixed amount of something delivers a lower welfare boost over time, with the (net) benefit possibly falling to zero or going negative. Most drugs show some level of dependency. Finally, addiction is when the more you do something, the worse off you will be if you stop doing it. A lot of drugs also have this effect, as do other things you get ‘used to,’ like exercising or having money to spend. These are all shown on the figure below. Many habits exhibit two of these effects or affect different people in different ways.

I have found this framework to be helpful in clarifying my thinking about which habits I should and should not take up.

We should be enthusiastic to accumulate habits that are characterised by appreciation and satisfaction. The stronger the effect the better. Dependency is undesirable, but you can still be better off from the habit if the effect isn’t too strong. Intense dependency is no good because eventually you will end up gaining nothing or losing from the habit. Addiction is not a problem so long as you will always want and be able to continue with the habit. If you will eventually stop, due to dependency, cost or unavailability, addiction will hurt you.

Appreciation and satisfaction combined is the ideal because you win out whether you continue the habit or not.

Addiction on top of serious dependency is the worst case because you will eventually be worse off whether you continue or not. These are the most problematic habits.

Appreciation and addiction together is fine, so long as you don’t expect to have to give up the habit for some reason. If you will, it will be a judgement call as to the initial gain and expected loss later on.

Satisfaction and dependency isn’t perfect but you can’t lose out overall. Even if dependency means you no longer gain from continuing the activity, you will continue to gain for having done it in the past.

The matrix below puts the above into a colourful tabular format.

Appreciation Satisfaction Dependency Addiction
Appreciation Good
Satisfaction Ideal Good
Dependency Impossible Can’t lose Ambiguous
Addiction Ambiguous Impossible Ambiguous but risky Ambiguous

The hard challenge is knowing which habits have which effects and with what intensity, but this framework at least allows you to ask the right questions and know what to do when you get the answers. It also makes it easy to understand and categorise the claims other people make about their habits.

For instance, someone who thinks it is worth ‘getting into’ fine food might claim that fine food is about appreciation. Someone like me who is skeptical of fine food, might think it is actually about dependency and/or addiction. I have in fact been going out of my way to buy cheap clothes, food, wine and beer lately in order to see if any dependency I currently have gradually disappears. If so I will be able to save money buying cheap goods for the rest of my life and be no worse off. I’ll let you know how it goes.

What got me thinking about all this was cleaning up my house on the weekend. I am skeptical of cleaning, beyond that required to stay organised and avoid disease, for the same reason most people are nervous about drug habits. People differ enormously in how much cleanliness they expect. When someone catches the ‘cleanliness bug’, I doubt they are left any better off than someone with low expectations. They could easily be worse off if they have to incur the cost of cleaning just to maintain their original level of well-being. That is to say, I think cleaning exhibits strong dependency and addiction. Amirite?

Most people are against cloning though I’ve never understood why. Is it just another technology that will be accepted once it’s possible?

“My prediction: Once a few thousand cloned humans are walking the earth, sneering at clones and people who want them will become as gauche as sneering at IVF babies and people who want them.”

Bryan Caplan on cloning

Here’s the craziest and most fascinating thing I’ve learnt in ages. Strap yourselves in:

The Sleeping Beauty problem: Some researchers are going to put you to sleep. During the two days that your sleep will last, they will briefly wake you up either once or twice, depending on the toss of a fair coin (Heads: once; Tails: twice). After each waking, they will put you to back to sleep with a drug that makes you forget that waking. When you are first awakened, to what degree ought you believe that the outcome of the coin toss is Heads?

First answer: 1/2, of course! Initially you were certain that the coin was fair, and so initially your credence in the coin’s landing Heads was 1/2. Upon being awakened, you receive no new information (you knew all along that you would be awakened). So your credence in the coin’s landing Heads ought to remain 1/2.

Second answer: 1/3, of course! Imagine the experiment repeated many times. Then in the long run, about 1/3 of the wakings would be Heads-wakings — wakings that happen on trials in which the coin lands Heads. So on any particular waking, you should have credence 1/3 that that waking is a Heads-waking, and hence have credence 1/3 in the coin’s landing Heads on that trial. This consideration remains in force in the present circumstance, in which the experiment is performed just once.

I will argue that the correct answer is 1/3.

Do you agree that the correct answer is 1/3? If so, you have just used the Self-Indication Assumption, which says “Given the fact that you exist, you should (other things equal) favor hypotheses according to which many observers exist over hypotheses on which few observers exist.” This seems very intuitive in the case above, but it can be taken to less obvious extremes.

For example, let’s imagine we have two remaining theories about the nature of the universe. One says that the universe is big: it contains a trillion galaxies. The other suggests the universe is even bigger than that: the universe contains a trillion trillion galaxies. We haven’t yet taken any scientific measurements that could distinguish between these two theories, so each is an equally good explanation for the world as we see it. But wait… we do have some evidence on the question: we exist! If we chose 1/3 in the coin tossing case, by analogy we should say that the theory which results in a trillion trillion galaxies is a trillion times more likely than that which only implies a trillion galaxies. The situation is exactly the same: observers will more often be right if they choose beliefs which imply that many such observers exist, in this case the belief that the universe is really really big.

As it happens we do have just such a theoretical debate about the nature of the universe! One interpretation of results in quantum physics says that the universe is constantly splitting into different worlds:

In many-worlds, the subjective appearance of wavefunction collapse is explained by the mechanism of quantum decoherence. By decoherence, many-worlds claims to resolve all of the correlation paradoxes of quantum theory, such as the EPR paradox and Schrödinger’s cat, since every possible outcome of every event defines or exists in its own “history” or “world”. In layman’s terms, there is a very large—perhaps infinite—number of universes, and everything that could possibly have happened in our past, but didn’t, has occurred in the past of some other universe or universes.

If the many worlds interpretation is correct, the universe is much much much bigger than in any other interpretation of quantum physics. If you are a ‘thirder’ you should now assign a higher probability to the many worlds interpretation than you did before in proportion to how many more observers would exist in the ‘many worlds’ universe than in the ‘single world’ universe.

Detractors of the Self-Indicating Assumption such as Nick Bostrum consider this the ‘reductio ad absurdum’ which shows it must be somehow wrong. As far as I can tell, this is baseless. The only reason they have for rejecting the conclusion is that it seems absurd on its face, but the ‘argument from personal incredulity’ is a weak one, especially on a topic like anthropics which humans did not evolve to think about easily.

If we had good evidence that the universe was actually small, this line of argument might be in conflict. But even before developing this theory we had good reason to think the universe was huge, and other reasons to think it could be even bigger than that! Both theory and experiment neatly point in the same direction: the universe is even bigger than you can imagine.

Join the debate about SIA Katja Grace has kindly started over at Meteuphoric.

Martin Rees on existential risk:

I am concerned about the threats and opportunities posed by 21st century science, and how to react to them. There are some intractable risks stemming from science, which we have to accept as the downside for our intellectual exhilaration and—even more—for its immense and ever more pervasive societal benefits. I believe there is an expectation of a 50% chance of a really severe setback to civilization by the end of the century. Some people have said that’s unduly pessimistic. But I don’t think it is: even if you just consider the nuclear threat, I think that’s a reasonable expectation.

If we look back over the cold war era, we know we escaped devastation, but at the time of the Cuba crisis, as recent reminiscences of its 40th anniversary have revealed, we were really on a hair trigger, and it was only through the responsibility and good sense of Kennedy and Khrushchev and their advisers that we avoided catastrophe. Ditto on one or two other occasions during the cold war. And that could indeed have been a catastrophe. The nuclear arsenals of the superpowers have the explosive equivalent of one of the US Air Force’s daisy cutter bombs for each inhabitant of the United States and Europe. Utter devastation would have resulted had this all gone off.

The threat obviously abated at the end of the cold war, but looking a century ahead, we can’t expect the present political assignments to stay constant. In the last century the Soviet Union appeared and disappeared, there were two world wars. Within the next hundred years, since nuclear weapons can’t be disinvented,  there’s quite a high expectation, there will be another standoff as fearsome as the cold war era, perhaps involving more participants than just two and therefore be more unstable. Even if you consider the nuclear threat alone, then there is a severe chance, perhaps a 50% chance, of some catastrophic setback to civilization.

There are other novel threats as well. Not only will technical change be faster in this century than before, but it will take place in more dimensions. Up to now, one of the fixed features over all recorded history has been human nature and human physique; human beings themselves haven’t changed, even though our environment and technology has. In this century, human beings are going to change because of genetic engineering, because of targeted drugs, perhaps even because of implants into their brain to increase our mental capacity. Much that now seems science fiction might, a century ahead, become science fact. Fundamental changes like that—plus the runaway development of biotech, possibly nanotechnology, possibly computers reaching superhuman intelligence—open up exciting prospects, but also all kinds of potential scenarios for societal disruption—even for devastation.

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Robert WiblinHi! I am a young Australian man ostensibly interested in the truth and maximising the total number of preferences that are ever satisfied, weighted by their intensity. I also enjoy reading and writing about the topics listed above. If you share my interests, friend me on , , or or subscribe to my RSS feed .

All opinions expressed here are at most mine alone, and have nothing to do with any past, present, future or far future employers.

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