Mindful tech

I often spend more time on distracting websites than I would like. Far beyond a mere producivity issue, aimless browsing and scrolling has become a major source of unhappiness for me.

Philosophy success story V: Bayesianism

This is part of my series on success stories in philosophy. See this page for an explanation of the project and links to other items in the series.

Philosophy success story IV: the formalisation of probability

Thus, joining the rigour of demonstrations in mathematics with the uncertainty of chance, and conciliating these apparently contradictory matters, it can, taking its name from both of them, with justice arrogate the stupefying name: The Mathematics of Chance (Aleae Geometria).

Philosophy success story III: possible words semantics

This is part of my series on success stories in philosophy. See this page for an explanation of the project and links to other items in the series.

Understanding central bank loss functions

Note: this post is unlikely to be of interest if you haven’t done a basic undergraduate course in macroeconomics.

The definition of effective altruism

William MacAskill proposes a definition of effective altruism (EA). I think having a definition is useful. It could allow effective altruists (and their critics) to have better, clearer conversations, and to avoid misconceptions.

The formal structure of ethical theories

What is utilitarianism? Utilitarianism is an ethical theory. It states that each of us ought to do whatever maximises everybody’s happiness. There are many ways to precisify this slogan, and hence many flavours of utilitarianism. The simplest one is hedonistic total utilitarianism. This diagram illustrates how someone who follows the blue lines at each decision node ends up endorsing hedonistic total utilitarianism.

Ontology and personal identity

ONTOLOGY AND PERSONAL IDENTITY, a play in one act and two scenes

Bertrand Russells Brief an Gottlob Frege, in dem er die 'Russellsche Antinomie' beschreibt (1902)

Staatsbibliothek zu Berlin, Preußischer Kulturbesitz

Taking the voodoo out of multiple regression

Valerio Filoso (2013) writes:

Most econometrics textbooks limit themselves to providing the formula for the $\beta$ vector of the type

Although compact and easy to remember, this formulation is a sort black box, since it hardly reveals anything about what really happens during the estimation of a multivariate OLS model. Furthermore, the link between the $\beta$ and the moments of the data distribution disappear buried in the intricacies of matrix algebra. Luckily, an enlightening interpretation of the $\beta$s in the multivariate case exists and has relevant interpreting power. It was originally formulated more than seventy years ago by Frisch and Waugh (1933), revived by Lovell (1963), and recently brought to a new life by Angrist and Pischke (2009) under the catchy phrase regression anatomy. According to this result, given a model with K independent variables, the coefficient $\beta$ for the k-th variable can be written as

where $\tilde x_k$ is the residual obtained by regressing $x_k$ on all remaining $K − 1$ independent variables.

The result is striking since it establishes the possibility of breaking a multivariate model with $K$ independent variables into $K$ bivariate models and also sheds light into the machinery of multivariate OLS. This property of OLS does not depend on the underlying Data Generating Process or on its causal interpretation: it is a mechanical property of the estimator which holds because of the algebra behind it.

Diagrams of linear regression

I made a big diagram describing some assumptions (MLR1-6) that are used in linear regression. In my diagram, there are categories (in rectangles with dotted lines) of mathematical facts that follow from different subsets of MLR1-6. References in brackets are to Hayashi (2000).

The expected value of the long-term future, and existential risk

I wrote an article describing a simple model of the long-term future. Here it is:

I took Oxford’s advanced undergraduate econometrics course. My experience of the course, and really of the entire field, was the following: the concepts are simple, the real challenge is making sense of notation so obfuscatory that you wonder if it’s done on purpose.

Relationships between the axiomatic systems of modal propositional logic

I made a diagram of this, based on Sider’s Logic for philosophy. An orange arrow from sytems S to system S’ means anything that is provable (and hence valid) in S is provable (and valid) in S’. I don’t add lables to the orange arrows since their meanings are clear. A green arrow from axiom schema to another says that the second schema is provable from the first in a particular system which I label.

Tripler ses dons

Les dons à des organismes d’intérêt général ouvrent droit à une réduction d’impôt au taux de 66%, dans la limite de 20% du revenu imposable. Cette réduction permet donc de tripler ses dons. En effet, si je souhaite dépenser 1000€ en donnant, je peux donner 3000€, et l’administration fiscale me rembourse 3000 * 0.66=2000€ sous forme de réduction d’impôt. Ce régime fiscal du don est extrêmement généreux: à titre de comparaison, la législation britannique du “Gift Aid” permet d’augmenter ses dons de 25% au lieu de 200% pour la France!

Philosophy success story II: the analysis of computability

a computing machine is really a logic machine. Its circuits embody the distilled insights of a remarkable collection of logicians, developed over centuries.

— Martin Davis (2000)

Philosophy success story I: predicate logic

This is part of my series on success stories in philosophy. See this page for an explanation of the project and links to other items in the series.

Philosophy success stories

Philosophical problems are never solved for the same reason that treasonous conspiracies never succeed: as successful conspiracies are never called “treason,” so solved problems are no longer called “philosophy.”

— John P. Burgess

Modesty and diversity: a concrete suggestion

In online discussions, the number of upvotes or likes a contribution receives is often highly correlated with the social status of the author within that community. This makes the community less epistemically diverse, and can contribute to feelings of groupthink or hero worship.

Oxford Prioritisation Project Review

By Jacob Lagerros and Tom Sittler

Extrême pauvreté: les surprenantes lois de puissance du don efficace

Inspiré d’un billet de Jeff Kaufman

On the experience of confusion

I recently discovered something about myself: I have a particularly strong aversion to the experience of confusion. For example, yesterday I was looking into the relationship between common knowledge of rationality and Nash equilibrium in game theory. I had planned to spend just an hour on this, leisurely dipping into the material and perhaps coming out with a clarified understanding. Instead, something else happened. I became monomanically focused on this task. I found some theorems, but there was still this feeling that things were just slightly off, that my understanding was not quite right. I intensely desired to track down the origin of the feeling. And to destroy the feeling. I grew restless, especially because I was making some progress: I wasn’t completely stuck, it felt like I must be on the cusp of clarity. The first symptom of this restlessness was skipping my pomodoro breaks, usually a sure sign that I am losing self-control and will soon collapse into an afternoon nap. The second smyptom was to develop an unhelpful impatience, opening ever more new tabs to search for the answer elsewhere, abandoning trains of thought earlier and earlier. In the end I didn’t have time to do any of the other work I had planned that day!

How much donation splitting is there, and should you split?

Cross-posted to the effective altruism forum.

The logical empiricist picture of the world

If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion.

— David Hume, An Enquiry Concerning Human Understanding, 1777, Section XII, Part 3

QALYs/$are more intuitive than$/QALYs

Cross-posted to the effective altruism forum.

Summary

Cost-effectiveness estimates are often expressed in $/QALYs instead of QALYs/$. But QALYs/$are preferable because they are more intuitive. To avoid small numbers, we can renormalise to QALYs/$10,000, or something similar.

sleeping beauty

In Adam Elga’s 2000 paper “Self-locating belief and the Sleeping Beauty problem”, he opens with:

In addition to being uncertain about what the world is like, one can also be uncertain about one’s own spatial or temporal location in the world. My aim is to pose a problem arising from the interaction between these two sorts of uncertainty, solve the problem, and draw two lessons from the solution.

Comment un individu peut-il faire une différence? Une mauvaise réponse, et deux bonnes

J’entends souvent des dialogues de ce genre quand il s’agit de faire un effort personnel pour aider les autres:

Alice: Face à toute la souffrance dans le monde, je me sens impuissante. Même si je changeais mon comportement, mon action individuelle ne résoudrait pas nos problèmes. Par exemple, même si je faisais un don pour aider un agriculteur pauvre au Kenya, d’autres ne donneront rien, et ce n’est pas grâce à moi que nous allons éliminer la pauvreté. Ce n’est pas à moi, mais aux puissants de ce monde d’agir.

Bernard: Si tout le monde raisonnait comme toi, nous ne ferions jamais rien pour aider les plus vulnérables. Au contraire, si chacun agit à son niveau, nous pouvons éliminer la pauvreté ensemble. Ainsi, en prenant partie à une action sociale, chacun peut changer les choses. Tu n’es donc pas impuissante.

A better formalism for interpreting confidence intervals

When we take a sample mean, we should think of it as a random variable, and our measured sample mean as a realisation of that random variable. The sample mean is a random variable because it is the result of random sampling. Repeated sampling involves observing repeated realisations of the random variable.

Consistent Vegetarianism and the Suffering of Wild Animals - Journal of Practical Ethics

A revised version of the essay I wrote for the Uehiro Prize has been published in the Journal of Practical Ethics.

Pourquoi je donne 10% de mon revenu

Oxford, 15 janvier 2016

Oxford Uehiro Prize in Practical Ethics, “How should vegetarians actually live?"

In 2016, I was the joint winner in the Undergraduate Category of the Oxford Uehiro Prize in Practical Ethics. Read my essay here, or below.