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Deductive logic is characterized by certainty: in a valid argument, when the premises are true, the conclusion '''must''' be true. The certainty, however, comes at a price.  Take a classic argument of deductive logic:

Deductive logic is characterized by certainty: in a valid argument, when the premises are true, the conclusion '''must''' be true. The certainty, however, comes at a price.  Take a classic argument of deductive logic:

'''Premises:'''

:'''Premises:''' All men are mortal, Socrates is a man.

All men are mortal,

:'''Conclusion:''' Socrates is mortal.

Socrates is a man

'''Conclusion:'''

Socrates is mortal  

The conclusion is "contained" in the premises.  In a sense the conclusion is "known" before it is elucidated.  The conclusion, "Socrates is mortal" is also less informative than the premises which imply not just that Socrates is mortal but that a lot of other beings (anyone for whom the term "is a man" applies) are also mortal.  As a result deductive logic is not thought to add to knowledge, merely to clarify it.  

The conclusion is "contained" in the premises.  In a sense the conclusion is "known" before it is elucidated.  The conclusion, "Socrates is mortal" is also less informative than the premises which imply not just that Socrates is mortal but that a lot of other beings (anyone for whom the term "is a man" applies) are also mortal.  As a result deductive logic is not thought to add to knowledge, merely to clarify it.  

Inductive logic is ampliative, but is famously less certain.  In a good inductive argument, even when the premises are true, it is still possible for the conclusion to be false.  A classic example of an inductive argument is:

Inductive logic is ampliative, but is famously less certain.  In a good inductive argument, even when the premises are true, it is still possible for the conclusion to be false.  A classic example of an inductive argument is:

'''Premise:'''

:'''Premise:''' All the many swans observed have been white.

All the many swans obversed have been white

:'''Conclusion:''' All swans are white.

'''Conclusion:'''

All swans are white

Before the discovery of Australia the premise was true someone following inductive logic would have reached the conclusion.  Given the existence of black swans in Australia, however, that conclusion is false.  [[David Hume]]'s 18th-century critique of induction remains a very pressing problem for disciplines like [[science]] which are commonly held to rely on inductive reasoning.

Before the discovery of Australia the premise was true someone following inductive logic would have reached the conclusion.  Given the existence of black swans in Australia, however, that conclusion is false.  [[David Hume]]'s 18th-century critique of induction remains a very pressing problem for disciplines like [[science]] which are commonly held to rely on inductive reasoning.

Another example of faulty logic would be when it comes to atheism. Atheists typically use many logical fallacies in an effort to convert people to their religion.  

Another example of faulty logic would be when it comes to atheism. Atheists typically use many logical fallacies in an effort to convert people to their religion.  

'''Premise:'''

:'''Premise:''' There is no emperical evidence for something.

There is no emperical evidence for something.

:'''Conclusion:''' The object does not exist.

'''Conclusion:'''

The object does not exist.

This logical fallacy acts as if absence of evidence is evidence of absence. This can be proven to be a faulty supposition because before America was discovered by Europeans, one could say there are only four continents based upon the evidence. This would be treated as a fact despite it being proven false later on. Also, this premise ignores the fact that there are multiple types of knowledge. There is empirical knowledge and then there is knowledge one has through faith. An example would be the knowledge that a mother loves her son. This cannot be proven to be a lie, but people have faith that is it true.

This logical fallacy acts as if absence of evidence is evidence of absence. This can be proven to be a faulty supposition because before America was discovered by Europeans, one could say there are only four continents based upon the evidence. This would be treated as a fact despite it being proven false later on. Also, this premise ignores the fact that there are multiple types of knowledge. There is empirical knowledge and then there is knowledge one has through faith. An example would be the knowledge that a mother loves her son. This cannot be proven to be a lie, but people have faith that is it true.