Buridan's ass
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Buridan's ass is the common name for the paradox which states that an entirely rational ass, placed exactly in the middle between two stacks of hay of equal size and quality, will starve since it cannot make any rational decision to start eating one rather than the other. The paradox is named after the 14th century French philosopher Jean Buridan.
The paradox was, however, not originated by Buridan himself. It is first found in Aristotle's De Caelo where Aristotle mentions an example of a man who remains unmoved because he is as hungry as he is thirsty and is positioned exactly between food and drink. Buridan nowhere discusses this specific problem but its relevance is that he did advocate a moral determinism whereby, save for ignorance or impediment, a human faced by alternative courses of action must always choose the greater good. Buridan allowed that the will could delay the choice in order more fully to assess the possible outcomes of the choice. Later writers satirised this view in terms of an ass who, confronted by two equally desirable and accessible bales of hay, must necessarily starve while pondering a decision.
A typical counter-argument is that rationality as described in the paradox is so limited as to be a straw man of the real thing, which does allow the consideration of meta-arguments. In other words, it's entirely rational to recognize that both choices are equally good and arbitrarily pick one instead of starving. This counter-argument is sometimes used as an attempted justification for faith. The argument is that, like the starving ass, we must make a choice in order to avoid being frozen in endless doubt. Other counter-arguments exist.
Buridan's ass sometimes finds mention in electrical engineering. Specifically, in digital logic, an analog-to-digital converter must convert a continuous voltage value into either a 0 or a 1. The voltage value represents the position of the ass, and the values 0 and 1 represent the bales of hay. Like the situation of the starving ass, there exists an input on which the converter cannot make a proper decision, resulting in a metastable state. Having the converter make an arbitrary choice in ambiguous situations does not solve the problem, as the boundary between ambiguous values and unambiguous values introduces another binary decision with its own metastable state. In the ass illustration, the ass cannot decide whether or not to choose arbitrarily and so starves to death.
[edit] See also
- Catch 22
- Hobson's choice
- Jean Buridan
- Metastability in electronics
- Dining philosophers problem
- Spontaneous symmetry breaking
[edit] References
- Zupko, Jack (2003) John Buridan. Portrait of a Fourteenth-Century Arts Master. Notre Dame, Indiana: University of Notre Dame Press. (cf. pp. 258, 400n71)
