Dear Kasili,

You ask the following; why is it impossible add to our store of knowledge in deductive reasoning?

This is so, because when deductive reasoning is the case, the conclusion derives necessarilly from the premises. In other words, the knowledge involved in the conclusion does not go beyond that involved in the premises. It is because of this that deductive reasoning is, say, a procedure of proof, not of discovering. If you want to appeal to a procedure of discovering and adding to your storage of knowledge, you have to employ either inductive reasoning or abductive reasoning. Of course, one's intuition and imagination are also a process of getting new knowledge.

Kind regards,

Orlando

True, deduction only gives us information that, in a sense, is already there. But sometimes it is not self-evident that it is already there and so the conclusion can be revelatory. A deductive proof may proceed step by step, each following from its predecessors, and the deducer may think, at some step, wow, when I started this deduction, I wouldn't have thought that that proposition could be concluded.

Knowledge needs to be distinguished from mere information. An agent may have information but lack the epistemic wherewithal for it to constitute knowledge.

We use two basic kinds of logic, inductive and deductive, in scientific arguments. When the major premise of an argument is based on observation or experience, it is an inductive argument. On the contrary, a deductive argument is one in which the major premise is based on a theory, rule, law, principle, or general understanding. Deductive method contributed much for the development of primitive science. This method was highly successful in mathematics, but the problem was that it did not succeed well in exploring the universe, and it was not all useful for arriving at new facts. For this, we have to use the inductive methods.

Induction involves generalization from the behaviour of a few samples to that of a population. For example, after smelling a number of jasmine flowers, you could make an inductive statement: “All jasmine flowers are scented”. According to inductive logic, if a situation or condition is true in all observed cases, then the situation or condition must be true in all cases. Therefore, after completing a series of experiments that support the inductive proposition, you can affirm that the proposition holds good in all cases.

Both inductive and deductive methods should be considered as different ways of approaching the same objective. In fact, a combination of induction and deduction is practiced in science now. The observations made through induction are further verified deductively through applications to new situations. The scientist proposes a hypothesis through induction and then tries to deduce the probability that it is false through empirical evidences. This is what is commonly known as the hypothetico-deductive method or inductive-deductive method.

Well appreciated for your insightful contributions

As an important research cycle, deductive reasoning has long been a legitimate approach to doing research in various disciplines. However, by using deductive reasoning, we should not resort to verifiability principle looking to confirm what we already know because finding evidence that backs up our theories is not useful. Rather, by using Karl Popper's falsifiability principle, we should expose the targeted generalization to an intersubjective testability cycle whose aim is to find evidence proving our theory is wrong. This approach can turn deductive reasoning into a priceless scientific endeavour.

...because the information contained in the conclusion is necessarily already contained in the premises (i.e., or it would not be deduction). Sheesh, you guys are wordy. ;-)

Very informative. Any credible scholarly references?

Funny, you are asking for support for a claim that seems obvious to me. Consequently, I am struggling a bit, not being a formal logician. The concept of entailment really captures the idea that the conclusion is already somehow in the premises. You are really asking about the properties of a type of formal system. https://en.wikipedia.org/wiki/Formal_system

Michael David Kurak Please scroll up to my comment. Is there anything there that you disagree with or would care to elaborate on? Thank you.

Hi Karl, There is nothing with which I would disagree. Nice response. Sorry that I missed it on first read down the page.

Thank you for the new additions on the debate

Deductive reasoning only proves the validity of an argument, not its truth or correctness per se, the value of its conclusion depends on the correctness of the premises; and these are for scientific purposes established via inductive means.

Well reasoned. A deductive argument is one in which the information in the conclusion is already contained in the premises. An inductive argument proceeds from experience to theoretical generalizations.