Demerits of Deduction are as follows:
1. It is harmful, when universal validity is claimed for the generalization arrived at by deduction, particularly, when the premises are incorrect or partially correct. If policy prescriptions are based on deduction, the consequences may be dangerous. The deductive “armchair” analysis should be taken with caution and care.
2. If the assumptions upon which deductive reasoning is based are untrue of partially true, the inferences drawn become automatically beyond truth, therefore, having no operational validity.
3. Deductive method is abstract. If a large dose of abstraction is used in theorising the result is the creation of “intellectual toys” and useless “implicit theorising.”