Consistency is very important in the deductive method.
The deductive method is a scientific method that considers that the conclusion is implicit within the premises . This means that the conclusions are a necessary consequence of the premises: when the premises turn out to be true and deductive reasoning is valid, there is no way that the conclusion cannot be true .
The first descriptions of deductive reasoning were made by philosophers in Ancient Greece , including Aristotle . It should be noted that the word deduction comes from the verb deduce (from the Latin deducĕre ), which refers to the extraction of consequences from a proposition.
Characteristics of the deductive method
The deductive method manages to infer something observed from a general law. This differentiates it from the so-called inductive method , which is based on the formulation of laws based on the facts that are observed.
In a research that uses the deductive method, therefore, hypotheses are developed based on existing theories. The purpose is to test the hypothesis in question by analyzing the implicit link between theories and specific cases.
There are those who believe, like the philosopher Francis Bacon , that induction is preferable to deduction , since it allows us to move from particularities to something general.
The deductive method can be direct proof or indirect proof.
Tools to consider
When appealing to the deductive method, a series of tools and instruments are usually used to achieve the proposed objectives of reaching the required point or clarification, always considering that thought goes from the general to the particular .
In this sense, we can state that it is common to use summaries , as they are the documents that allow us to focus clearly and concisely on the essentials of a matter. However, it should also be noted that, in the same way, synthesis and synopsis are used.
But the list of procedures and tools goes much further. Thus, maps , graphs , diagrams and demonstrations could not be ignored in it either. The latter in particular help especially to demonstrate that a principle or law is true, and to do so they start from all established truths as well as logical relationships.
The deductive method is used in social sciences and formal sciences.
Types of deductive method
The deductive method can be divided according to whether it is direct and has an immediate conclusion (in cases in which the judgment is produced from a single premise without others that intervene) or indirect and has a mediate conclusion (the major premise houses the universal proposition, while that the minor includes the particular proposition: the conclusion, therefore, is the result of the comparison between both).
Other classifications refer to types of deductive method such as modus ponens (which indicates that if S is true and S implies T, then T will be true), modus tollens (if S implies T and T is not true, then S is not true either). ) and the syllogism (the conclusion is reached based on two assumptions that share a term in common with what is given as a result).
In all cases, researchers who use the deductive method begin their work by raising assumptions (coherent among themselves) that are limited to incorporating the main characteristics of the phenomena. The work continues with a procedure of logical deduction that ends in the statement of the general laws .
Advantages and disadvantages
Philosophy and epistemology scholars list various advantages when resorting to the deductive method in research. Thus it is argued that this method stands out for its usefulness when testing a hypothesis .
On the other hand, the deductive method contributes to the measurement of concepts in a quantitative way and the generalization of results . It is even stated that it can be developed more quickly compared to other methods.
As for its disadvantages, it should be considered that deductive reasoning allows guaranteeing the validity of the argument, but cannot ensure the falsity or truth of the conclusion because it is not oriented towards content, but rather towards argumentative formality.
A logical fallacy , in this context, arises when an argument is constructed using the deductive method based on false or erroneous premises. For example: if you start from the premise that Americans speak English and then express that Juan speaks English , you could conclude that Juan is American . However, that conclusion may be wrong.
Examples of deductive method
Among the examples that we can use to understand more exactly what the concept of deductive method means would be the following: if we start from the statement that all English people are punctual and we know that John is English , we can conclude by saying that, therefore, John It is punctual .
Let's look at another example. Starting from the axiom that dogs are animals that have four legs and bark and knowing that Firuláis is a quadruped animal and communicates by barking , it is possible to ensure that Firuláis is a dog .
In the field of mathematics, the deductive method is also widely used. Thus, in this subject we can find examples that demonstrate it, like this one: if A is equal to B and B is equal to C , we can determine that A and C are equal .