The difference between the inductive and deductive method lies in the direction of the reasoning to reach the conclusions. Inductive vs Deductive, Read this!
Both the inductive and the deductive method are logical reasoning strategies since the inductive uses particular premises to reach a general conclusion, and the deductive uses general principles to reach a specific conclusion.
Both methods are important in the production of knowledge. During a scientific investigation it is possible to use one or the other, or a combination of both, depending on the field of study in which it is performed.
At present, the method used in experimental sciences is the so-called hypothetical-deductive method.
Inductive vs Deductive
Below is the tabulated brief explanation of Inductive vs Deductive for clearer understanding:
|Inductive method||Deductive method|
|Definition||It is a way of reasoning based on a series of particular observations that allow the production of laws and general conclusions.||It is a way to reason and explain reality based on laws or general theories towards particular cases.|
|Reasoning Direction||From particular to general.||From the general to the particular.|
|Knowledge Areas||It was the method used in experimental sciences. It is currently used as part of the scientific method in general.||Formal sciences such as mathematics and logic.|
The inductive method is used starting from particular cases to arrive at a general proposition.
The use of inductive reasoning was and is of great importance in scientific work in general since it involves the collection of data on specific cases and their analysis to create theories or hypotheses.
Characteristics of the inductive method
- Follow the direction from the bottom up, from the particular to the general.
- Part of empirical observations and then build theories on the observed.
- It is still used in science, but within the hypothetical-deductive method.
- It is limited to the observation of phenomena.
- Their conclusions are probable and can become false.
The observation in the inductive method
Observation is one of the key aspects in the inductive method. The experience of the phenomena is important in the scientific areas where data on observed facts and phenomena are collected, to arrive at a general hypothesis or theory.
For scientific knowledge to have weight, it is important that numerous observations be made on a fact so that, if similar conditions exist, a generalization can be made.
In addition to observation, the inductive method uses experimentation to obtain the necessary data that leads to the approach of a general conclusion.
Steps of the inductive method
- Facts and phenomena are observed and recorded.
- Data collected from various observations and their possible relationships are compared and analyzed.
- Generalizations (or laws) are established.
- These generalizations are used to predict future phenomena.
Examples of the inductive method
A simple example is to find out the result of the sum of the internal angles of a triangle.
First, the internal angles of a triangle are added and it is noted that they result in 180º. Then, the same activity is performed with another triangle, and the result is the same, 180º. This action is repeated (observation and comparison of each sum) several times.
The result remains the same. When all the information is gathered, the general conclusion is reached that the internal angles of a triangle total 180º. In other words, from this series of observations and their comparison, it is concluded that this will continue to occur.
Another example is when it is observed that all objects that rise tend to fall. If you take a series of objects and then drop them, you can see that each one falls towards the floor. This concludes that there must be some property or force that causes objects to attract each other (in this case the mass of each object).
Thus, through this type of observations, the law of gravity was established, formulated by the English naturalist physicist Isaac Newton (1643-1727). This law basically proposes that all bodies that have mass attract each other. This is how Newton checked it through several observations. It can be said, then, that “everything that goes up has to go down.”
Limitations of the inductive method
Science is constantly developing. Even with general laws that predict events or phenomena, those who are dedicated to science know that there may be cases in which the conclusions do not apply.
This is why the inductive method as such may be insufficient when it comes to building knowledge and broadening the understanding of reality if its conclusions are not constantly tested.
According to the Scottish philosopher David Hume (1711-1776), there is no absolute certainty that what we observe a certain number of times, will be repeated in the same way in the future.
For the Austrian science philosopher Karl Popper (1902-1994), the problem of induction is that it is not always possible to establish a universal truth, based on particular observations. For Popper, the important thing is to find facts that can falsify (refute) the conclusions in science.
A famous example is that of the statement “all swans are white. ” At some point in Europe it was believed that this was so. It was observed that the swans were characterized by being all white, this statement being generalized as a fact.
This is because there was no experience to the contrary (black swans had never been seen). However, some time later, specimens of black swans were taken from Australia to Europe, and this simple fact refuted the idea that all swans were white.
The deductive method is a type of reasoning used to apply laws or theories to singular cases .
It is the method used in formal sciences, such as logic and mathematics. In addition, deductive reasoning is key in the application of laws to particular phenomena that are studied in science.
It is a hierarchical form of reasoning, since it is based on generalizations, which gradually apply to particular cases. This makes the deductive method very useful for producing knowledge of previous knowledge. It is also practical when it is impossible or very difficult to observe the causes of a phenomenon, but those consequences it produces.
Characteristics of the deductive method
- Follow the direction from the top down, from the general to the particular.
- It is the method used in formal sciences.
- It is based on the theory to predict observable phenomena through hypotheses.
- The conclusion is contained in the premises.
- If the premises are valid and true, the conclusion is also true.
- Their conclusions should lead to logical and rigorous consequences.
- By itself it does not produce new knowledge.
Examples of the deductive method
A classic example of this method is as follows:
- Premise 1: All men are mortal.
- Premise 2: Socrates is a man.
- Conclusion: So Socrates is mortal.
It is possible to observe that the conclusion is already implicit in the premises.
Another example is presented when thinking about living beings and their genetics. It is known that all living things have DNA (deoxyribonucleic acid). So, if at any time you are going to analyze a living organism, it follows that this organism will have DNA.
Validity and truthfulness in the deductive method
In the deductive method, erroneous conclusions can be incurred if the premises are not true. For example, considering the following premises:
- Premise 1: All men are bad.
- Premise 2: Your grandfather is a man.
- Conclusion: Therefore, your grandfather is bad.
This argument is valid, however, it is not true. Its validity lies in the fact that the conclusion is implicit in the premises. But the statement contained in premise 1 (“all men are bad”) is not a true statement, since its truthfulness does not follow from the premises, so it is still necessary to prove it.
In this sense, the conclusions of the deductive method are valid and correct when the premises are also valid. In the same way, if the premises are true, the conclusion will also be true.
The method currently used in scientific research is the so-called hypothetical-deductive method. This method basically synthesizes the main aspects of the inductive and deductive methods.
Steps of the hypothetical-deductive method
- The observation and analysis of a series of phenomena is performed.
- A hypothesis is proposed based on the results of what was observed in order to explain these phenomena. For the hypothesis to be valid, it must be possible to test it.
- When a hypothesis postulates something, it follows that if the same conditions that caused a phenomenon to occur, the consequences predicted by the hypothesis should be given.
- The hypothesis is verified from experiments.
- If the hypothesis is verified, then it is accepted. If your assumptions are not verified, it is rejected.