Inductive arguments make generalisations from experience of particular examples .
For example: making a generalisation about ravens, after seeing a group of black ravens.
'Every raven I have ever seen has been black.
There are one hundred ravens in the tower of London.
Therefore, every raven in the tower of London is black.'
Inductive Arguments: Problem
Conclusions reached by inductive arguments are contingent – their reliability is questionable.
Hume said that there is no reason why the future should resemble the past, so making generalisations based on past experience is not particularly reliable.
Inductive arguments increase the probability of the conclusion, but are still not certain.
So, while the premises of the raven argument increase the probability of the truth of the conclusion, the conclusion is contingent - it could be either true or false.
Deductive arguments apply general rules to particular examples.
For example, applying a general rule about mortality to the example of Socrates:
‘All men are mortal, Socrates is a man, therefore Socrates is mortal’.
In a deductive argument, provided that the premises are true, the truth of the conclusion is guaranteed.
Deductive Arguments: Problem
Deductive arguments don’t provide any new knowledge about the world - their conclusions are trivial.
Deductive arguments are essentially tautologies – provided the premises are true, the conclusion can be deduced through an a priori process of reasoning, so they provide no new information about the world.
Furthermore, it is not always possible to prove the truth of the premises - if the premises cannot be proven to be true, then neither can the conclusion.