Enter a curated archive of paradoxes, thought experiments, systems, and riddles. Browse the vault or draw a random entry.
Abelson's paradox is an applied statistics paradox identified by Robert P. Abelson. The paradox pertains to a possible paradoxical relationship between the magnitude of the r2 (i.e., coefficient of determination) effect size and its practical meaning.
The Abilene paradox is a collective fallacy, in which a group of people collectively decide on a course of action that is counter to the preferences of most or all individuals in the group, while each individual believes it to be aligned with the preferences of most of the others. It involves a breakdown of group communication in which each member mistakenly believes that their own preferences are counter to the grou
The accuracy paradox is the paradoxical finding that accuracy is not a good metric for predictive models when classifying in predictive analytics. This is because a simple model may have a high level of accuracy but too crude to be useful.
Acosmism, held in contrast or equivalent to pantheism, denies the reality of the universe, seeing it as ultimately illusory (the prefix 'ἀ-' in Greek meaning negation; like 'un-' in English), and only the infinite unmanifest Absolute as real. Conceptual versions of Acosmism are found in eastern and western philosophies.
The Aharonov–Bohm effect, sometimes called the Ehrenberg–Siday–Aharonov–Bohm effect, is a quantum-mechanical phenomenon in which an electrically charged particle is affected by an electromagnetic potential ( φ {\\displaystyle \\varphi } , A {\\displaystyle \\mathbf {A} } ), despite being confined to a region in which both the magnetic field B {\\displaystyle \\mathbf {B} } and electric field E {\\displaystyle \\mathbf {E} }
Air conditioning, often abbreviated as A/C (US) or air con (UK), is the process of removing heat from an enclosed space to achieve a more comfortable interior temperature and, in some cases, controlling the humidity of internal air. Air conditioning can be achieved using a mechanical 'air conditioner' or through other methods, such as passive cooling and ventilative cooling.