Law of Detachment
The law of detachment (also known as affirming the antecedent and Modus ponens) is the first form of deductive reasoning. A single conditional statement is made, and a hypothesis (P) is stated. The conclusion (Q) is then deduced from the statement and the hypothesis. The most basic form is listed below:
- P→Q (conditional statement)
- P (hypothesis stated)
- Q (conclusion deduced)
In deductive reasoning, we can conclude Q from P by using the law of detachment. However, if the conclusion (Q) is given instead of the hypothesis (P) then there is no valid conclusion.
The following is an example of an argument using the law of detachment in the form of an if-then statement:
- If an angle A>90°, then A is an obtuse angle.
- A=120°
- A is an obtuse angle.
Since the measurement of angle A is greater than 90°, we can deduce that A is an obtuse angle.
Read more about this topic: Deductive Reasoning
Famous quotes containing the words law of, law and/or detachment:
“Here, lads, we live by the law of the taiga. But even here people manage to live. D’you know who are the ones the camps finish off? Those who lick other men’s left-overs, those who set store by the doctors, and those who peach on their mates.”
—Alexander Solzhenitsyn (b. 1918)
“But the creative person is subject to a different, higher law than mere national law. Whoever has to create a work, whoever has to bring about a discovery or deed which will further the cause of all of humanity, no longer has his home in his native land but rather in his work.”
—Stefan Zweig (18811942)
“There is no detachment where there is no pain. And there is no pain endured without hatred or lying unless detachment is present too.”
—Simone Weil (1909–1943)