Process of elimination is a
logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure o ...
al method to identify an entity of interest among several ones by excluding all other entities. In
educational testing, it is a process of deleting options whereby the possibility of an option being correct is close to zero or significantly lower compared to other options. This version of the process does not guarantee success, even if only one option remains, since it eliminates possibilities merely as improbable. The process of elimination can only narrow the possibilities down, and thus, if the correct option is not amongst the known options, it will not arrive at the truth.
Method
The method of elimination is
iterative. One looks at the answers, determines that several answers are unfit, eliminates these, and repeats, until one cannot eliminate any more. This iteration is most effectively applied when there is
logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure o ...
al structure between the answers – that is to say, when by eliminating an answer one can eliminate several others. In this case one can find the answers which one cannot eliminate by eliminating any other answers and test them alone – the others are eliminated as a
logical consequence
Logical consequence (also entailment or logical implication) is a fundamental concept in logic which describes the relationship between statement (logic), statements that hold true when one statement logically ''follows from'' one or more stat ...
; this is the idea behind optimizations for computerized searches when the input is sorted – as, for instance, in
binary search
In computer science, binary search, also known as half-interval search, logarithmic search, or binary chop, is a search algorithm that finds the position of a target value within a sorted array. Binary search compares the target value to the m ...
.
In order for the method to work it is necessary to list all possible, even improbable, possibilities. Any omissions render the method invalid as a
logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure o ...
al method.
Medicine
A process of elimination can be used to reach a
diagnosis of exclusion
A diagnosis of exclusion or by exclusion (''per exclusionem'') is a diagnosis of a medical condition reached by a process of elimination, which may be necessary if presence cannot be established with complete confidence from history, examination o ...
. It is an underlying method in performing a
differential diagnosis
In healthcare, a differential diagnosis (DDx) is a method of analysis that distinguishes a particular disease or condition from others that present with similar clinical features. Differential diagnostic procedures are used by clinicians to di ...
.
See also
*
Disjunctive syllogism
In classical logic, disjunctive syllogism (historically known as ''modus tollendo ponens'' (MTP), Latin for "mode that affirms by denying") is a valid argument form which is a syllogism having a disjunctive statement for one of its premises.
...
*
Law of excluded middle
In logic, the law of excluded middle or the principle of excluded middle states that for every proposition, either this proposition or its negation is true. It is one of the three laws of thought, along with the law of noncontradiction and t ...
*
Philosophical razor
*
Troubleshooting
*
twenty questions Spoken word game using logic.
References
* Richard L. Burden, J. Douglas Faires (2000). ''Numerical Analysis'', 7th ed. Brooks/Cole. {{ISBN, 0-534-38216-9.
Philosophical logic
Philosophical methodology