Inductive, Deductive and Circular Logic

Inductive Logic:

Observations:

X then Y

X then Y

X then Y

X then Y

X then Y

X then Y

X then Y

X then Y

X then Y

X then Y

Therefore:

Assumption: if X then Y (major premise)

In the above, the conclusion is proven by the afore-mentioned observations.  The observations—taken with the physical senses: sight, smell, sound, taste, touch—are the evidence.

Deductive Logic:

Assumption: if X then Y (major premise)

Observation: X (minor premise)

Conclusion: Y (conclusion)

From sensual observations, assumptions are created. Then from assumptions and observations conclusions are drawn.
                       
Senses--> Induction-->Deduction

Circular Logic:

No observed evidence exists to support the assumption.  Instead, an assumption is made with unobserved evidence.

Assumption: if A then B (major premise)

                        Observation: A (minor premise)
                        Conclusion: B (conclusion)
                                    Therefore:
                                                A then B
                                                        Therefore:
                                                              Assumption: if A then B (major premise)

No observed evidence exists to support the assumption: if A then B.  The only evidence that exists to support the assumption, if A then B, is the  unobserved evidence delineated above.  A then B was never observed.