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 and/or detachment:
““Teacher, which commandment in the law is the greatest?” He said to him, “You shall love the Lord your God with all your heart, and with all your soul, and with all your mind.’ This is the greatest and first commandment. And a second is like it: You shall love your neighbor as yourself.’ On these two commandments hang all the law and the prophets.””
—Bible: New Testament, Matthew 22:36-40.
“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)