Thinking Complete

This post is largely based on a lightning talk I gave at a Genesis event on metacognition, with some editing to clarify and expand on the arguments.  Reductionism is the strategy of breaking things down into smaller pieces, then trying to understand those smaller pieces and how they fit together into larger pieces. It’s been an excellent strategy for physics, for most of science, for most of human knowledge. But my claim is that, when the thing we're trying to understand is how to think, being overly reductionist has often led people astray, particularly in academic epistemology. I’ll give three examples of what goes wrong when you try to be reductionist about epistemology.  Firstly, we often think of knowledge in terms of sentences or propositions with definite truth-values - for example, “my car is parked on the street outside”. Philosophers have debated extensively what it means to know that such a claim is true; I think the best answer is the bayesian one, where we assign...

This post discusses two books by Michael Strevens: The Knowledge Machine: How Irrationality Created Modern Science and Thinking Off Your Feet: How Empirical Psychology Vindicates Armchair Philosophy . I loved the former, which tries to answer the core question in philosophy of science: why does science work so well? It’s a masterful synthesis of previous ideas and important new arguments, and it’ll be my go-to recommendation from now on for people interested in the field. The latter was… slightly less persuasive. But let’s start with the good stuff. The Knowledge Machine begins with a review of two of the key figures in philosophy of science: Popper and Quine. Historically, philosophers of science focused on identifying a “scientific method”: a specific way of generating theories, designing experiments, and evaluating evidence which, when followed, led scientists to the truth. Popper’s influential account of the scientific method focused on scientists trying to refute their hypothese...

“The progress of Science is generally regarded as a kind of clean, rational advance along a straight ascending line; in fact it has followed a zigzag course, at times almost more bewildering than the evolution of political thought. The history of cosmic theories, in particular, may without exaggeration be called a history of collective obsessions and controlled schizophrenias; and the manner in which some of the most fundamental discoveries were arrived at reminds one more of a sleepwalker’s performance than an electronic brain’s.” - Arthur Koestler The Sleepwalkers is an enlightening history of astronomy from the Ancient Greeks to Newton. It particularly focuses on three characters who shifted scientific consensus from the Ptolemaic geocentric model of the solar system to a heliocentric one: Copernicus, Kepler, and Galileo. And characters is the right word, because Koestler digs into their personal quirks and foibles with gusto. If he is to be believed, these three key scientist...

This month, I've compiled a list of issues that I've been wrong about. International development. I'm pretty libertarian on domestic issues, and so I automatically assumed the same mindset regarding the international economy: thinking that the "Washington consensus" was a broadly good idea, and that encouraging free trade is the biggest priority. However, I was wrong on that: I underestimated the extent to which Asian growth relied on strong and stable governments, and the extent to which deregulation eroded aspects of African governments necessary for private enterprise. I want to put up a few political blog posts in the next month which explore these ideas further. Moral realism. As a good reductionist, I used to think that moral realism was entirely incoherent. Then I read Parfit on personal identity, and had conversations with a few friends (notably Paul F-R), and realised that insofar as we can identify what is "rational" and "irrational...

Thanks to Tom for pointing me to this presentation by a couple of Oxford philosophers who may just have solved Fermi's Paradox (the puzzle of why we haven't seen any alien civilisations, given that plausible estimates for terms in the Drake equation predict that there should be many thousands in this galaxy alone). The main idea is actually quite simple: that people have generally tried to find plausible expected values for each term, then multiplied them together to give an expected number of alien civilisations in the thousands or millions. But if we instead multiply together a whole probability distribution for each term, we get the same mean but a median less than 10, and a double-digit probability that there are no other alien civilisations (the first couple of slides explain this quite well). Their final best guess, given our observations so far, is that there's something like a 40% chance that we're alone in the universe. While this isn't a particularly d...

I was recently discussing with a friend whether or not competitive debating makes you better at figuring out what is actually true. This is an interesting question, because debating influences people in a variety of different ways. The most basic is that participating in debates, or preparing for them, teaches you a lot of facts about the world; I would know much less about international politics in particular were it not for debating. It also markedly improves your ability to notice flaws and fallacies in arguments, which obviously helps you avoid falling for them. This skill can extend too far, though: debaters can be very good at rebutting even very sensible arguments. In the American Parliamentary style of debate, the proposing team is allowed to choose and prepare in advance any motion which is not so blatantly, obviously true that it would be impossible to debate (e.g. "murder is bad"). A lot of proposition teams skirt quite close to that line - but even so, opposing t...

I recently sat the All Souls Fellowship exam, called by some the " world's hardest exam ". It requires you to write twelve essays for four papers over two days; the breadth and novelty of the questions make it a fascinating experience. Two of the papers were "general papers" and two were in a humanities subject of your choice (in my case, philosophy); most papers had around 25 questions. I've summarised my answers below, as well as noting some of the other particularly interesting questions. General paper I: 1. How should you prepare for the end of the world? I started off with a somewhat emotional argument about the badness of death on an individual level. I referred to Epicurus' argument that we have nothing to fear from death because when we are dead, we will not have any preferences about it at all - but argued, in response, that having preferences about future states of the world is a foundation of our lives. In terms of the end of the ...

I want to investigate the nature of and limits of mathematics. To do that, I'll explore logic, set theory, computability, information theory and philosophy. Be warned that this essay is rather long; it starts relatively easy and gets significantly harder. I hope everyone will get something out of it (including my tutors!) but if you're new to mathematics, that might not be much. If you're philosophically inclined, definitely look at the last section on Truth and Induction. Any discussion or errata are of course very welcome. Let's start with some historical background. Although the Babylonians were able to do some interesting calculations (particularly astronomical), mathematics in the sense of deductive arguments from premises to conclusions began with Thales, Pythagoras and their disciples. Greek maths was focused on geometry, which was formalised by Euclid into 5 axioms - foundational assertions - from which he proved many theorems. Euclidean geometry (as formalis...