“Any error or mistake in reasoning is called
The pattern of mistakes that appear in deductive
argument of a certain specifiable form, it is a
mistake in form of argument it is called Formal
Illicit Major & Illicit Minor
Drawing an Affirmative Conclusion
from a negative premise.
“Avalid form of categorical syllogism must contain
exactly the three terms, each of which is used in
the same sense throughout the argument”.
Therefore, 6th September is fruit.
“In a valid standard form of categorical
syllogism, the middle term(M) must be
distributed in at least one premise”.
All Russians were .
All anarchists were .
Therefore, all anarchists were Russians.
Illicit process of Major & Minor
“A valid standard form of categorical
syllogism, if either term is distributed in
conclusion then it must be distributed in the
All dogs are
No cats are dogs
Therefore, No cats are .
All mobiles are electronic device
All mobiles are
Therefore, all are electronic device.
“No standard form categorical syllogism
having two negative premise is valid”.
Therefore, some magicians are not
Drawing an affirmative conclusions from a
“If either premise of a valid standard form
categorical syllogism is negative, the
conclusion must be negative”.
Some artists are poets
Therefore, some artists are
“No valid standard form categorical
syllogism with a particular conclusion
can have universal premise”.
All household pets are domestic animals
No unicorn are domestic animals