Deduction and Induction :
Arguments can be divided into two groups, that is to say, Deductive arguments and Inductive arguments.
A deductive argument is an argument that makes the claim that its premises support the conclusion conclusively. While on the other hand an inductive argument is the one which claims that its premises support the conclusion with some degree of probability.
For example
All men are mortal.
Ali is a man.
Therefore Ali is mortal.
The above argument is a deductive argument. Because here we can see that the premises of this argument support the conclusion conclusively, that is to say, there is some logical relationship, the conclusion necessarily follows from the premises.
On the other hand,
Ali is mortal.
Akbar is mortal.
Aslam is mortal.
Therefore All men are mortal.
This argument is an inductive argument as the premises of this argument support the conclusion with some degree of probability. Though it is highly probable but we cannot say with certainty that all men are mortal. To be certain we need future evidences too, that is the death of all human beings.
Another important thing to note is that we often assume or take for granted some premises in deduction to be true and then draw conclusion, while in induction we directly refer to the facts and then make a generalization.
For example;
All kings are mortal.
Faisal is a king.
Therefore Faisal is mortal.
In this deductive argument to find out whether its propositions are true or false, we will have to assume other two propositions for the truth of “All kings are mortal”
All men are mortal.
All kings are men.
Therefore all kings are mortal.
Now to prove that “All men are mortal” we will have to assume other two propositions that is to say;
All animals are mortal.
All men are animals.
Therefore All men are mortal.
Similarly to prove that All animals are mortal we will have to assume other two propositions and so on. It is rather better for us to see our premises and conclusions (propositions) inductively, that is, to go directly to the facts.
In spite of the above interpretation both are two different processes of reasoning and hence both are important. For example we can say deductively that
All patients of malaria are cured by quinine.
Mr X is a patient of malaria.
Therefore Mr. X is cured by quinine.
And inductively we can say,
Mr. X is being patient of malaria cured by quinine.
Mr. Y is being patient of malaria cured by quinine.
Mr. Z is being patient of malaria cured by quinine.
Therefore all patients of malaria are cured by quinine.
Difference between Deduction and Induction;
Deduction goes from general laws to particular facts and induction goes from particular facts to general laws.
The aim of induction is to see whether our argument tallies with the actual world
or not. While the aim of deduction to see the form of the argument, that is to say,
how it is formed. Deduction demands that thought should agree with itself and
Induction demands that thought should agree with the actual reality.
3. Deduction employs the methods of synthesis while induction employs the method
of analysis. Deduction is concerned with syllogism, which means putting the
premises together (process of synthesis) and then drawing a conclusion from them.
On the other hand induction has to discover the causal connection among the facts
for which analysis (a process to separate the relevant facts from the irrelevant
facts which go together) is necessary.
Induction is based upon the law of nature and the law of uniformity of nature,
while deduction is based on laws of thought.
Validity is the attribute of deductive argument while probability is the attribute of
Inductive argument. A deductive argument must be valid or invalid, while an inductive argument is more or less probable
Arguments can be divided into two groups, that is to say, Deductive arguments and Inductive arguments.
A deductive argument is an argument that makes the claim that its premises support the conclusion conclusively. While on the other hand an inductive argument is the one which claims that its premises support the conclusion with some degree of probability.
For example
All men are mortal.
Ali is a man.
Therefore Ali is mortal.
The above argument is a deductive argument. Because here we can see that the premises of this argument support the conclusion conclusively, that is to say, there is some logical relationship, the conclusion necessarily follows from the premises.
On the other hand,
Ali is mortal.
Akbar is mortal.
Aslam is mortal.
Therefore All men are mortal.
This argument is an inductive argument as the premises of this argument support the conclusion with some degree of probability. Though it is highly probable but we cannot say with certainty that all men are mortal. To be certain we need future evidences too, that is the death of all human beings.
Another important thing to note is that we often assume or take for granted some premises in deduction to be true and then draw conclusion, while in induction we directly refer to the facts and then make a generalization.
For example;
All kings are mortal.
Faisal is a king.
Therefore Faisal is mortal.
In this deductive argument to find out whether its propositions are true or false, we will have to assume other two propositions for the truth of “All kings are mortal”
All men are mortal.
All kings are men.
Therefore all kings are mortal.
Now to prove that “All men are mortal” we will have to assume other two propositions that is to say;
All animals are mortal.
All men are animals.
Therefore All men are mortal.
Similarly to prove that All animals are mortal we will have to assume other two propositions and so on. It is rather better for us to see our premises and conclusions (propositions) inductively, that is, to go directly to the facts.
In spite of the above interpretation both are two different processes of reasoning and hence both are important. For example we can say deductively that
All patients of malaria are cured by quinine.
Mr X is a patient of malaria.
Therefore Mr. X is cured by quinine.
And inductively we can say,
Mr. X is being patient of malaria cured by quinine.
Mr. Y is being patient of malaria cured by quinine.
Mr. Z is being patient of malaria cured by quinine.
Therefore all patients of malaria are cured by quinine.
Difference between Deduction and Induction;
Deduction goes from general laws to particular facts and induction goes from particular facts to general laws.
The aim of induction is to see whether our argument tallies with the actual world
or not. While the aim of deduction to see the form of the argument, that is to say,
how it is formed. Deduction demands that thought should agree with itself and
Induction demands that thought should agree with the actual reality.
3. Deduction employs the methods of synthesis while induction employs the method
of analysis. Deduction is concerned with syllogism, which means putting the
premises together (process of synthesis) and then drawing a conclusion from them.
On the other hand induction has to discover the causal connection among the facts
for which analysis (a process to separate the relevant facts from the irrelevant
facts which go together) is necessary.
Induction is based upon the law of nature and the law of uniformity of nature,
while deduction is based on laws of thought.
Validity is the attribute of deductive argument while probability is the attribute of
Inductive argument. A deductive argument must be valid or invalid, while an inductive argument is more or less probable
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