Deduction is a method of thinking, the consequence of which is a logical conclusion, where a particular conclusion is deduced from a general one.
“From just one drop of water, a person who knows how to think logically can deduce the existence of the Atlantic Ocean or Niagara Falls, even if he has not seen either one or the other,” this is how the most famous literary detective reasoned. Taking into account small details invisible to other people, he built impeccable logical conclusions using the method of deduction. It was thanks to Sherlock Holmes that the whole world learned what deduction is. In his reasoning, the great detective always started from the general picture - the whole picture of the crime with the alleged criminals, and moved to specific moments - he considered each individual, everyone who could commit the crime, studied the motives, behavior, evidence.
This amazing Conan Doyle hero could guess from the soil particles on his shoes which part of the country a person came from. He also distinguished one hundred and forty types of tobacco ash. Sherlock Holmes was interested in absolutely everything and had extensive knowledge in all areas.
What is the deductive method?
The deductive method (from Latin deductio - deduction) is a method of thinking , the consequence of which is a logical conclusion, where a particular conclusion is deduced from the general. The whole essence of the deductive method is that a person begins to build a logical chain based on a hypothesis, the accuracy of which he has no doubt. In order to prove a hypothesis, it is necessary to make observations and draw conclusions. In the process of observation, generally accepted and recognized facts are applied.
To make it easier to understand what the deductive method is, let's turn to the book “Thinking Slow... Solve Fast,” authored by Nobel Prize winner Daniel Kahneman. The book describes the so-called “fast thinking,” which is responsible for instantaneous awareness of the surrounding space. This type of thinking forces a person to classify his instinctive sensations. Based on this, a person most often makes irrational decisions that turn out to be wrong.
In order to ensure the conscious formation of thoughts, decisions, conclusions and assessments, it is necessary to use a system of “slow” thinking. How does this manifest itself? For example, a woman found her husband's wedding ring on the living room table. The first impulse, of course, will be to get angry with your spouse and suspect him of all mortal sins. However, the woman immediately remembers that a light bulb in their living room had burned out, and she asked her husband to replace it. The light in the room is on, which means the man has fulfilled the request. It follows that he had to bring a stepladder and tools from the garage. Because the man had to wear gloves, he took off the ring to make it easier for him. Afterwards, he simply forgot to put it on because he was late for work. The reason was found, a family quarrel was avoided - this is an example of “slow” thinking, which helped the woman see all the details and come to the right conclusion.
This type of thinking is the basis of the deductive method. Deduction allows you to draw a particular conclusion based on general facts. Let's take the same gold ring. We know that all metals are capable of conducting current, and gold is undoubtedly a metal. From this we can conclude that a gold ring is also capable of passing current. We applied knowledge from the general education school curriculum and made a private conclusion. In doing so, we used the deductive method of thinking.
Modern epistemology
The ability to reason logically and base one's knowledge on facts rather than assumptions was valued not only in the past. It will always be useful in our world. Modern thinkers believe that in philosophy, induction is an argument based on the degree of probability. Its methods are applied depending on how suitable they are for solving the problem at hand.
In practical life it looks like this. If you want to go to a hotel, you start looking at reviews about it and see that the hotel has a high rating. This is an inductive argument. But for the final decision, you need to understand whether you have enough budget for such a vacation, whether you personally will like living there and how objective the assessments were. That is, you will need additional information.
Deduction is used in cases where the so-called validity criterion can be applied. For example, your vacation is possible only in September. A highly rated hotel closes in August, but another hotel stays open until October. The answer is obvious - you can only go on vacation to places where you can do it in the fall. This is how deduction is used not only in philosophy, but also in everyday life.
Examples of the deductive method
Deductive thinking has been around since the time of Aristotle, who analyzed every conclusion along with its premises and conclusion. Cognition through the deductive method is based on the relationship of the constituent components.
Let's go back to the example with the gold ring. Hypothesis A states that all metals carry current. If this hypothesis is correct, then hypothesis B that gold, like a metal, also passes current, is correct. So the B hypothesis follows from the A hypothesis. If someone manages to prove that gold does not transmit current, then this will mean that hypothesis B is incorrect. From this we can conclude that judgment A will also be erroneous.
Judgments that contain statements of immutable truths are premises. In our example, these are “metals pass current” and “gold is a metal.” Judgments that follow from the premises and put a logical point are a conclusion, or a consequence. “Gold also passes current”—that’s the conclusion.
Why is the one-sided method dangerous?
Conclusions in inductive reasoning can be erroneous. And if we constantly rely on them and do not check them deductively, then we can move away from the real meaning of the connection between facts. But aren’t we guided in our lives – subconsciously and one-sidedly – only by inductive conclusions? For example, in given circumstances, we have always taken such and such an approach to solving a problem, and this has brought us success. This means that we will continue to act in this way without changing anything. But our experience is not facts, but just our idea of them. But often we treat our concepts as certain axioms. This leads to incorrect conclusions.
Differences from the inductive method
The inductive method is the exact opposite of the deductive method, and is based on the transition from the particular to the general. This can be observed more clearly in medicine, when a doctor, based on the patient’s symptoms, makes a diagnosis. From a deductive point of view, the whole “picture” must first be assessed in order to reach a correct conclusion. Using this method, the doctor must first use the general term “cold” and work from there. Influenza means that a person must have symptoms.
If we talk about differences, it should be mentioned that deductive thinking is more generalizing and global. Inductive thinking is based on subjective hunches. However, both methods are interrelated. At the beginning, until a common feature is discovered in various phenomena, the movement occurs from the particular to the general, that is, induction is used. By combining particular cases, induction allows us to obtain general knowledge. After establishing a general feature, thinking goes in the opposite direction - from the general to the specific. This is a deductive method.
Model that limits cognition
Induction in philosophy is the deliberate simplification of complex structures to create an understandable picture of the world. When we observe different phenomena, we generalize them. From this we draw conclusions about the connections between phenomena and put them together into a single picture. It allows us to make choices and set priorities, to determine what is important to us and what is not. But if we lose control over the situation and begin to replace facts with our own opinion about them, then we will inevitably begin to adjust everything we see to suit ourselves. Thus, the presence of induction alone limits cognition. After all, as a rule, it is incomplete. Therefore, almost all universal generalizations made with its help imply the possibility of exceptions.
Where is deduction used?
Every day, when faced with various circumstances, our brain builds logical chains that are invisible to many. When deciding what to wear in the morning, we study the weather outside the window. We have two messages in our heads: it’s cold outside, and warm clothes protect us from the cold. These are two general knowledges. Based on this, we come to the understanding that we need to dress warmly - this is the conclusion.
The deductive method is present in our everyday life, but we may not understand it. However, when it comes to professional activities, a person consciously uses deduction to solve specific problems. The method of deductive thinking is used in many directions:
- disputes and discussions - using deduction, obvious statements are given with which the opponent has to agree, thereby accepting your point of view;
- mathematics - a good example is geometric problems from the school curriculum. To prove the theorem, the student must use generally accepted and proven axioms;
- philosophy - the whole essence of the deduction method here is that any hypothesis must be substantiated using only logical evidence;
- forensics - upon arriving at the crime scene, the expert uses the overall picture of the incident. This helps him find individual circumstances and new details;
- science - a scientist takes as the basis of his work some hypothesis that has not yet been proven or disproven. Based on the hypothesis, the scientist derives consequences that he will try to discover during the research.
Deduction and Induction – Bacon vs. Aristotle
In the history of philosophy, these two methods of cognition have been constantly opposed. Aristotle, by the way, was the first to describe induction, but called it dialectics. He stated that the conclusions obtained in this way were the opposite of the analytical ones. Bacon, as we have already seen, preferred induction. He developed several rules for obtaining knowledge using this method. Cause-and-effect relationships between different phenomena, from his point of view, can be established by analogy of differences, similarities, residues, as well as the presence of accompanying changes. Absoluteizing the role of experiment, Bacon stated that in philosophy induction is a universal method of epistemology. As, in fact, in any science. However, eighteenth-century rationalism and the development of theoretical mathematics cast doubt on his conclusions.
How to learn to think deductively?
We've talked before about the slow mindset. If you want to learn the deductive method, you will need to be observant. Be “corrosive”, try to pay attention to even the most inconspicuous details. Start small, for example, by studying the arrangement of furniture in a room when you are visiting someone. When talking to a person, pay attention to how he talks, gestures, and where he looks. Over time, you will learn to notice what is hidden from prying eyes.
If you don't have a small notebook, now is the time to buy one. Carry it with you always to record all your observations. Over time, spatial descriptions will turn into iron facts. Don't forget that you will need an extensive knowledge base. Expand your horizons every day: read, watch films and listen to music of different genres, travel, meet people of different professions and interests.
How to develop deduction in yourself?
Deduction requires observation. First of all, you need to learn to be observant and attentive. Not every person has deductive abilities. Those who are always in a hurry, in a hurry, cannot think slowly. They act in a hurry.
But deductive thinking can be cultivated in yourself. Start small. Take a closer look at things that are happening. Evaluate and analyze. Of course, theory alone will not suffice here. Learning deduction is a long process.
There is special literature on deductive logic. The works talk about special exercises that develop mental abilities, attentiveness, and observation.
Here are some techniques that contribute to the development of deduction:
1. Solving mathematical problems. We are taught logic in school. Meaningful and analyzed information allows you to draw a conclusion, that is, find an answer. You can solve not only mathematical problems, but also physical and chemical ones. Solving them requires the use of formulas. A person comprehends the text and data of the task, determines which formula should be used. Through logical conclusions, he, one way or another, comes to the right decision.
2. Expand your horizons. Books for developing deduction recommend not limiting yourself to studying one area. It is important to understand many areas. Music, art, literature, chemistry and other sciences help increase your mental potential. Engage in self-development.
3. Be meticulous. Study should not be superficial. If you decide to limit yourself to studying one area, do it with the utmost care. Immerse yourself in the process. Get into the details.
4. Develop flexibility of thinking. Having solved the problem in the usual way, think about other options. They certainly exist. Going one way is not always wise. Sometimes there are shortcuts that lead to the correct answer. Put this rule into practice. Offer several ways to solve a particular problem.
5. Become observant. When contacting people, pay attention to the gestures, facial expressions, and posture of the interlocutor. If you return from work, note those details that were not there in the morning. Gradually you will get used to being attentive.
6. Develop involuntary attention. Some little things may not be obvious. But even the slightest changes should be noted with peripheral vision. You can play the game. Ask someone to remove a small object from the room. Look around. Try to understand what exactly was removed?
7. Combine deduction and induction. You can learn from the example already described. Ask your household members to add something to the room or change some detail in the interior. Can you notice the changes?
There are many ways to develop deductive thinking. Collect puzzles, mosaics, solve puzzles, get books on entertaining mathematics. Logical problems are often given here.
Deductio
The deductive method involves a transition from a general conclusion about an object of a certain class to private, individual knowledge about an individual object from this group. It can be used to predict events that have not yet occurred. The basis in this case is the general studied patterns. Deduction is widely used in proving, justifying, and testing assumptions and hypotheses. Thanks to her, the most important scientific discoveries were made. The deductive method plays a vital role in the formation of the logical orientation of thinking. It promotes the development of the ability to use known information in the process of mastering new material. Within the framework of deduction, each specific case is studied as a link in a chain, and their relationship is examined. This allows you to obtain data that goes beyond the initial conditions. Using this information, the researcher makes new conclusions. When the original objects are included in newly emerging connections, previously unknown properties of the objects are revealed. The deductive method promotes the application of acquired knowledge in practice, general theoretical principles, which are exclusively abstract in nature, to specific events that people encounter in life.
How to check the degree of development of logical thinking
Psychologists diagnose logical thinking. In some cases, teachers can assess skills and the degree of maturity of intellectual activity. Determining the level is quite difficult. Because errors are possible. A discount is made on the new conditions in which the test subject is located, on the complexity of the didactic material and other factors. Because not all forms of logic are equally developed in one person. Especially if he did not undergo special training and did not train. The average indicators are recorded in writing in order to compare the initial and final results after a certain development.
The tasks and assignments are selected by a psychologist. Usually, for testing purposes, it is enough to selectively compile material from Eysenck questionnaires and similar ones. Also included are questions from the Wonderlica questionnaire (Vanderlik), processed in Russian.
The task is to examine the extent to which the subject is able to use the tools of formal logic. Without special training, it is used chaotically, without a system.
Psychologists use logical tasks as effective material. There are many of them on the Internet, but not many check the actual logic. Therefore, it is better to treat the material on the sites with a sufficient degree of skepticism.
Conversations show good results. In the course of the subject’s reasoning, inaccuracies, harmony of statements and arguments, features of movement and trajectories of thoughts are already visible. Not all psychologists are competent enough to immediately talk and evaluate the reasoning of their patients. Therefore, out of necessity, they attract specialists who are familiar with formal logic and freely use its methods in practice.
In some cases, it is advisable to use text materials, simple journalistic articles, and popular science texts. This will allow you to evaluate the degree of effectiveness of working with what you have written.
Psychologists have many more methods at their disposal. For example, visual material on cards. The patient is provided with a series of picture cards as stimulus material. They depict situations. The task is to arrange the displayed events in exact sequence. Then tell the story that turned out.
The examination may take a lot of time. Depends on what aspects of logical thinking the specialist evaluates. On average, diagnosis takes from 60 to 180 minutes. Plus or minus.
Logical thinking tests are also carried out as part of the identification of mental disorders. But here it is enough to limit ourselves to the “exclude the unnecessary” techniques and working with cards. As described above. In patients with schizophrenia and psychosis, a split in the processes of intellectual activity is observed. Therefore, they are not capable of even basic logical thinking. Disturbances in logical thinking also occur in healthy people. But not in such a rude manner. They are rather inaccurate in nature. But in general, the nature of the reasoning is correct.
If a person does not have the opportunity to contact a psychologist, you can test yourself. For this, resources with Eysenck and Wonderlick tests will come to the rescue. It is not necessary to undergo diagnostics often. Selective development of certain aspects of intellectual activity is possible. It turns out that the tasks are solved without problems, but in other situations the subject is helpless or is at the same level as he was. The information content of such self-diagnosis is minimal.
What types of logical thinking exist
In psychology, there are several types of the named skill (or, rather, groups of skills and approaches). Based on the main way of perceiving and reproducing information.
Abstract logical thinking
This is the basis of the named concept. When they talk about logic, they mean precisely this part of the activity. Its foundation lies in the ability to non-verbally, with great speed and efficiency, build complex connections, find relationships, notice subtle facts, and classify them. Also, a person with a high culture of this kind is able to quickly sift out the “husks”, find implicit connections, and come to non-trivial conclusions. Independently putting forward complex hypotheses and formulating one’s own theories are also important skills within the framework of this method of mental activity.
An important quality that should not be forgotten is consistency. That is, individual aspects, conclusions, must be consistent with each other and with the general outline of the reasoning. Otherwise, this is “pseudology” and is of little use. Possible flaws in your own reasoning also need to be noticed and corrected in a timely manner. Mistakes are possible even with developed skills.
The difference between the degrees of development lies in the ability to find and eliminate them. The abstract variety requires a long development and forms the basis for all other types. With sufficient mastery, problems no longer arise.
Verbal and logical thinking
A subtype based on verbal abilities. That is, the ability to put your thought into speech and convey it to the audience. Including in writing. Skill plays a huge role in the work of speakers, writers and publicists, writers. It is impossible to do without the ability to consistently formulate thoughts for scientists and workers in the educational environment.
There is also an important pairing skill. Be able to evaluate the speech of another, notice all inaccuracies and contradictions. The same goes for text. The ability to analyze other people's thoughts is indispensable when writing reviews or working as a public speaker (for example, a lawyer). Paradoxically, a well-developed abstract form of logical thinking does not mean that a person will automatically be quite effective in verbal form.
To become competent in this area, you must have a wide vocabulary and literate speech skills. The ability to accurately convey thoughts is born with experience and develops with it. Therefore, everything can be improved with the proper number of hours of practice. Another name for this group of skills is verbal-logical thinking. Specific examples where an understanding of this approach is required are speeches in court. The lawyer is a reference example. On the one hand, he must be able to prepare his own speech and defend his position if the other party or the court has questions. On the other hand, to detect inaccuracies in the opponent’s speech, to catch him using ambiguous wording and so on. Such a person must have an extensive arsenal of skills: from on-site system analysis to competent argumentation, the ability to debate, and quickly navigate the situation.
Visual-logical thinking
Required for situational analysis. It plays a major role in the work of criminologists, forensic experts, and doctors of various specialties. Workers of such profiles deal mainly with visual, visual material: be it the scene of investigative actions, radiography (image), a picture on the screen of an ultrasound machine, or something else in the same spirit. The specialist’s task is to track important visual data and interpret it correctly, integrate it into the overall picture and create a consistent concept. In the case of doctors, it may look like this. A radiology specialist takes a picture, deciphers it and gives general information about the condition of the lungs (optional). He does not make diagnoses. Its contribution is to assess the characteristics of the organ and search for anomalies. This requires developed logical thinking. The therapist or pulmonologist, based on X-ray data and other objective studies, already draws conclusions on the diagnosis. Which requires systematization and in-depth analysis skills.
It is not always necessary for all three varieties to be developed to an equal, high degree. It all depends on the person himself, his desires, professional activities, and experience. It's all about skills and willingness to practice. In any case, you cannot do without logical thinking. It lies at the basis of knowledge. Moreover, one cannot achieve success in academic and scientific activities if one does not master such a rich toolkit.
