A Logical Theory Dr. Akhlas Ahmed IBT, City Campus Feb 4 th , 2017 Lecture # 3
Its aim is to establish its conclusion. The implicit or explicit claim, in a deductive argument, is therefore that if the premises are true then the conclusion is completely certain to be true as well.
An inductive argument aim is to show that its conclusion is probably true although not certainly true.
In inductive argument claims (in so many words) only that if the premises are true, then the conclusion is likely or reasonable (but not certain).
Deductive indicators...When conclusion with wording such as! Therefore it must be that… It necessarily follows that… Therefore it is certain that… It is conclusively proven that…These phraes are called deductive indicators.
Inductive indicators...When conclusion with wording such as! Therefore it is probably the case that… It is likely that… Therefore it is reasonable to conclude that… These phraes are called inductive indicators.
A deductive argument that succeeds in showing that its conclusion must be true if its premises all are true is called a valid deductive argument.
A deductive argument that fails to show that its conclusion must be true if its premises are true is called an invalid deductive argument.
Valid…example: 1. All human beings are mammals.2. All mammals are warm-blooded.3. Therefore it must be that all human beings are
warm-blooded.Invalid…example:1. All human beings are mammals.2. All dogs are mammals. 3. Therefore it must be that all human beings are
dogs..
1. All students are millionaires.2. All millionaires are Buddhists.3. Therefore, all students must be Buddhists.In this example argument, about students and Buddhists, was valid, but unsound
1. All whales are mammals.2. All mammals are animals.3. Therefore, it must be that all whales are
animals. This example is both valid and sound:
“If your father is a poor man,it is your fate but,
if your father-in-law is a poor man,it's your stupidity.”
“The more you learn, the more you know,The more you know, the more you forgetThe more you forget, the less you know
So.. why learn.”
“A bus station is where a bus stops.
A train station is where a train stops.
On my desk, I have a work station.... what more can I say........”