The idea that perceptual and cognitive systems must incorporate knowledge about the structure of the environment has become a central dogma of cognitive theory. In a Bayesian context, this idea is often realized in terms of “tuning the prior”—widely assumed to mean adjusting prior probabilities so that they match the frequencies of events in the world. This kind of “ecological” tuning has often been held up as an ideal of inference, in fact defining an “ideal observer.” But widespread as this (...) viewpoint is, it directly contradicts Bayesian philosophy of probability, which views probabilities as degrees of belief rather than relative frequencies, and explicitly denies that they are objective characteristics of the world. Moreover, tuning the prior to observed environmental frequencies is subject to overfitting, meaning in this context overtuning to the environment, which leads (ironically) to poor performance in future encounters with the same environment. Whenever there is uncertainty about the environment—which there almost always is—an agent's prior should be biased away from ecological relative frequencies and toward simpler and more entropic priors. (shrink)
A widespread assumption in the contemporary discussion of probabilistic models of cognition, often attributed to the Bayesian program, is that inference is optimal when the observer's priors match the true priors in the world—the actual “statistics of the environment.” But in fact the idea of a “true” prior plays no role in traditional Bayesian philosophy, which regards probability as a quantification of belief, not an objective characteristic of the world. In this paper I discuss the significance of the traditional Bayesian (...) epistemic view of probability and its mismatch with the more objectivist assumptions about probability that are widely held in contemporary cognitive science. I then introduce a novel mathematical framework, the observer lattice, that aims to clarify this issue while avoiding philosophically tendentious assumptions. The mathematical argument shows that even if we assume that “ground truth” probabilities actually do exist, there is no objective way to tell what they are. Different observers, conditioning on different information, will inevitably have different probability estimates, and there is no general procedure to determine which one is right. The argument sheds light on the use of probabilistic models in cognitive science, and in particular on what exactly it means for the mind to be “tuned” to its environment. (shrink)
: Vasubandhu, an advocate of the idealist Yogācāra school of Buddhism, argues that the nonexistence of external objects can be inferred from the appearance of nonexistent things in perceptual illusion. The idealist view and the argument from illusion are criticized by proponents of the realist Nyāya school on the grounds that illusory experience is parasitic upon veridical experience. The parasitism objection successfully defeats Vasubandhu's argument from illusion but fails to decisively disprove the idealist view because it remains possible that each (...) illusory experience gets its content from a previous illusory experience in an infinite chain. (shrink)
Vasubandhu is perhaps the most influential figure in the history of Buddhist philosophy, yet the very breadth of his contribution across many schools and traditions has led to a fragmentation of his works, as interpreters have tended to read them through the lens of narrow scholastic perspectives, finding little continuity or coherence. Some modern scholars, doubtful that anyone could have held such varied views, have gone so far as to divide Vasubandhu himself into two distinct philosophers, with two different and (...) irreconcilable views. In his recent book, Paving the Great Way: Vasubandhu’s Unifying Buddhist Philosophy, Jonathan Gold offers for the first time a unified picture of Vasubandhu, extracting the driving... (shrink)
Embodiment, the explicit dependence of cognition on the properties of the human body, is the foundation of contemporary cognitive science. Ballard et al.'s target article makes an important contribution to the embodiment story by suggesting how limitations on neural binding ability lead to deictic strategies for many tasks. It also exploits the powerful experimental method of instrumented virtual reality. This commentary suggests some ways in which the target article might be misinterpreted and offers other cautions.
The radical empiricist theory of the Quartz & Sejnowski target article would result in a brain that could not act. The attempt to bolster this position with computational arguments is misleading and often just wrong. Fortunately, other efforts are making progress in linking neural and cognitive development.
Le groupe Féminin Masculin Avenir s’est constitué dès l’automne 1967. Il a participé aux événements de mai 68, devenant alors Féminisme Marxisme Action. Il s’est ensuite dissous dans le Mouvement de libération des femmes lorsque celui-ci a éclaté en 1970.
Loin dêtre un auteur mineur, thuriféraire dun naïf laissez-faire, Bastiat apparaît comme le précurseur de la plupart des courants libéraux contemporains.Il est frappant de constater que le diagnostic porté par Bastiat sur le fonctionnement de la démocratie demeure dune brûlante actualité.Cest donc injustement que Hayek a méconnu son devancier : une étude critique de la philosophie juridique et politique du Français lui aurait permis déviter quelques inconséquences, telle sa théorie des fonctions non coercitives de lEtat.Far from being a minor economist, (...) or flattering some naive laissez-faire, Bastiat is indeed a precursor of most of the contemporaneous views defending liberalism.It is striking to note how much Bastiats diagnosis about the workings of democracy applies with acuity to the current world.Thus, Hayek unduly disregarded his precursor: a critical study of Bastiats philosophy and conception of law would have allow Hayek to not fall into some traps, such as his theory on the non-coercitive functions of government. (shrink)