Compare and Contrast Inductive and Deductive Method

The deductive reasoning, inductive reasoning, and hypothetic-deductive or hypothesis testing are the three scientific methods, which are referred to by the generic name of the scientific method.

The first thing which caught my attention was the fact that the first two scientific methods have a problem as the name is difficult to distinguish, given that in a language context they can represent just one concept with two statements: reasoning in one direction or the other, from general to specific, or vice versa.

Logically, the problem derives from the conceptual difficulty of clearly separating the elements of a scientific reasoning from the other; obviously, the chosen terms do not help retain these two concepts of scientific method or scientific reasoning in the memory. The first name of the third scientific method does not help much either.

Both deductive reasoning and inductive reasoning can go from general to specific and vice versa, in one direction or the other. Both use logic and arrive to a conclusion. As a last resort, they always have philosophic substratum elements. Both tend to be susceptible to empirical testing.

Although the deductive reasoning or deductive logic is more appropriate of the formal sciences and the inductive reasoning of the empirical sciences, nothing prevents the indiscriminate application of a scientific method, or any other method, to a particular theory.

In my opinion, without trying to create a controversy on this subject, the fundamental difference of the deductive method and the inductive method is that the first aims to indicate, through pure logic, the conclusion in its entirety based on a few premises. So that the veracity of the conclusions is guaranteed; that is, if the applied logic is not invalidated. It is about the axiomatic model proposed by Aristotle as the ideal scientific method.

On the contrary, the inductive method creates laws based on the observation of the facts, by generalizing the observed behavior; actually, what achieves is a type of generalization without obtaining a demonstration of the aforementioned laws or set of conclusions through logic.

Such conclusions could be false and, at the same time, the partial application of logic carried out could maintain its validity. For that reason, the inductive method needs an additional condition; its application would be valid if there is no case that does not fulfill the proposed model.

The hypothetical-deductive method, or the hypothesis testing, does not raise any problems in principle, given that its validity depends on the results of the appropriate empirical testing.

The hypothetical-deductive method tends to be used to improve or clarify previous theories according to new knowledge where the model’s complexity does not allow logical formulations. Therefore, it has a predominantly intuitive character and needs, not only in order to reject a theory but also to impose its validity, the contrasting of its conclusions.

One could suggest the deductive reasoning, intuitive reasoning, and hypothesis testing as denominations for the three main variants of the scientific method, or for that matter, any set of words that refer to their fundamental differences or elements and do not raise any problems for the linguistic memory. However, in the exposition I will stick to the nomenclature generally used.

The General Theory of the Conditional Evolution of Life fits in perfectly with a theory based on the hypothetical-deductive, or hypothesis testing method.

Darwin’s theory of evolution, on the other hand, would fit in the inductive reasoning; but despite finding opposing examples, the scientific community does not invalidate it but adapted to square off any triangle. Why would it be?

As was previously mentioned, every theory should be able to withstand refutation; however, a theory that does not allow refutation by any conceivable fact is not scientific. The impossibility of disproving a scientific theory is not a virtue but a defect.

Deductive reasoning works from the "general" to the "specific". This is also called a "top-down" approach. The deductive reasoning works as follows: think of a theory about topic and then narrow it down to specific hypothesis (hypothesis that we test or can test). Narrow down further if we would like to collect observations for hypothesis (note that we collect observations to accept or reject hypothesis and the reason we do that is to confirm or refute our original theory). In a conclusion, when we use deduction we reason from general principles to specific cases, as in applying a mathematical theorem to a particular problem or in citing a law or physics to predict the outcome of an experiment.

Inductive reasoning works the other way, it works from observation (or observations) works toward generalizations and theories. This is also called a “bottom-up�? approach. Inductive reason starts from specific observations (or measurement if you are mathematician or more precisely statistician), look for patterns (or no patterns), regularities (or irregularities), formulate hypothesis that we could work with and finally ended up developing general theories or drawing conclusion. In a conclusion, when we use Induction we observe a number of specific instances and from them infer a general principle or law. Inductive reasoning is open-ended and exploratory especially at the beginning. On the other hand, deductive reasoning is narrow in nature and is concerned with testing or confirming hypothesis.

Properties of Deduction

In a valid deductive argument, all of the content of the conclusion is present, at least implicitly, in the premises. Deduction is nonampliative. If the premises are true, the conclusion must be true. Valid deduction is necessarily truth preserving. If new premises are added to a valid deductive argument (and none of its premises are changed or deleted) the argument remains

valid. Deductive validity is an all-or-nothing matter; validity does not come in degrees. An argument is totally valid, or it is invalid.

Properties of Induction

Induction is ampliative. The conclusion of an inductive argument has content that goes beyond the content of its premises. A correct inductive argument may have true premises and a false conclusion. Induction is not necessarily truth preserving. New premises may completely undermine a strong inductive argument. Inductive arguments come in different degrees of strength. In some inductions the premises support the conclusions more strongly than in others.

Intuitive Reasoning A third type of reasoning, intuitive reasoning, is what many young children use, as well as older children/adults in highly unfamiliar situations. Intuitive reasoning has to do with the way something appears to be, how something "seems" or "looks", and is based on unverified guesses. While it may seem to be very rudimentary, it is very useful in giving a starting point from which induction or deduction can proceed. It is the chief type of reasoning used by early elementary students, and students must be shown the flaws in it by the use of cognitive conflict in order to learn to move past intuition towards induction and deduction.

In most subject areas, both deductive and inductive methods are taught as ways to reach a solution. In mathematic and science related subjects, the method of reasoning is most apparent. However, in all subjects of education, a method of reasoning is in place. The following are some resources to see how specific methods influence a variety of subject areas.

Cultural Variations in Approaches to Learning

"Teachers may use inquiry methods that emphasize deductive approaches to learning, analytical examinations of details or parts, or the solving or the problems by examining the relationship of one part to another. This linear model, moving sequentially from the specific to the general and examining objects/concepts without a context may not be the preferred approach to learning for some children from groups of color. Students of color often use a more inductive problem solving and reasoning process. They may use observed instances in context to generate an idea or a concept. They move from whole to part from the general to the specific"( Sheets, 2005, p. 160).

In logic, we often refer to the two broad methods of reasoning as the deductive and inductive approaches.

Deductive reasoning works from the more general to the more specific. Sometimes this is informally called a "top-down" approach. We might begin with thinking up a theory about our

topic of interest. We then narrow that down into more specific hypotheses that we can test. We narrow down even further when we collect observations to address the hypotheses. This ultimately leads us to be able to test the hypotheses with specific data -- a confirmation (or not) of our original theories.

Inductive reasoning works the other way, moving from specific observations to broader generalizations and theories. Informally, we sometimes call this a "bottom up" approach (please note that it's "bottom up" and not "bottoms up" which is the kind of thing the bartender says to customers when he's trying to close for the night!). In inductive

reasoning, we begin with specific observations and measures, begin to detect patterns and regularities, formulate some tentative hypotheses that we can explore, and finally end up developing some general conclusions or theories.

These two methods of reasoning have a very different "feel" to them when you're conducting research. Inductive reasoning, by its very nature, is more open-ended and exploratory, especially at the beginning. Deductive reasoning is more narrow in nature and is concerned with testing or confirming hypotheses. Even though a particular study may look like it's purely deductive (e.g., an experiment designed to test the hypothesized effects of some treatment on some outcome), most social research involves both inductive and deductive reasoning processes at some time in the project. In fact, it doesn't take a rocket scientist to see that we could assemble the two graphs above into a single circular one that continually cycles from theories down to observations and back up again to theories. Even in the most constrained experiment, the researchers may observe patterns in the data that lead them to develop new theories.