Reading Comprehension (RC) | Logical arguments are usually classified as either deductive

Logical arguments are usually classified as either deductive or inductive, depending on the process used to arrive at them. In the process of deduction, you begin with some statements, called premises, which are assumed to be true, and you then determine what else would have to be true if the premises are true. For example, in mathematics, you can begin with some axioms and then determine what you can prove to be true given those axioms are true. With deduction, you can provide absolute proof of your conclusions, since your premises are considered correct. The premises themselves, however, remain unproven and unprovable; they must be accepted on face value, or by faith, or for the purpose of exploration.

On the other hand, in the process of induction, you begin with some data, and then determine what general conclusion(s) can logically be derived from that data. In other words, you determine what theory or theories could explain the data. For example, you note that the probability of becoming schizophrenic is greatly increased if at least one parent is schizophrenic, and from that you conclude that schizophrenia may be inherited. That is certainly a reasonable hypothesis given the data. Note, however, that induction does not prove that the theory is correct. There are often alternative theories that are also supported by the data. For example, the behavior of the schizophrenic parent may cause the child to be schizophrenic, not the genes. What is important in induction is that the theory does indeed offer a logical explanation of the data. To conclude that the parents have no effect on the schizophrenia of the children is not supportable given the data, and would not be a logical conclusion.

Both deduction and induction by themselves are inadequate for a scientific approach. While deduction gives absolute proof, it never makes contact with the real world; there is no place for observation or experimentation - no way to test the validity of the premises. And, while induction is driven by observation, it never approaches actual proof of a theory. Accordingly, a synthesis of these two logical approaches is required for an actual scientific method.