6 Ways to Develop your Deductive Reasoning

Updated By Staff Writer on July 10, 2020

Deductive reasoning is often associated with one of the most famous fictional detectives of all, Sherlock Holmes. This art is something that most people never fully tap into during their lifetimes but Sherlock was able to master it! Developing this skill can help you predict behaviors, formulate strategies for unfamiliar situations, and overall increase your perception of your surroundings.


What is deductive reasoning? This is an important life skill that is used to form conclusions about the world around you. Also known as top-down reasoning, this method is used in the scientific method and can be used in everyday life as well. In order for deductive reasoning to work, there must be two true statements and an inference based on those statements. As a simple example, if ducks are birds and all birds have wings, then you can conclude that ducks have wings. This reasoning forms the backbone of Sherlock’s detective skills.

What Is the Difference Between Inductive and Deductive Reasoning?

Deductive reasoning isn’t the only type of reasoning and logic skill that is important to develop. Inductive reasoning is another style of logic, but it differs from deductive reasoning in a few ways.

While deductive reasoning is a top-down form of thinking, inductive reasoning is a bottom-up type of thinking. With this method, you’ll first form a conclusion, or hypothesis, then seek the evidence to support your conclusion. In contrast, deductive reasoning analyzes two true statements before forming a conclusion.

Inductive reasoning can sometimes lead to false conclusions and weak arguments, since it uses specific circumstances to make generalizations. For example, if you have an older brother who likes to play baseball, you could use inductive reasoning to falsely conclude that all older brothers like to play baseball. Often, inductive reasoning is used by children to help formulate their sense of the world. There may have been a time when you were young that you realized your life experiences were not the same as others and, depending on your age, it might have seemed illogical.

However, inductive reasoning can be helpful in making predictions about the future. For example, if a teacher notices higher test scores when tests are given in the morning, they might continue to administer tests earlier in the day. This is useful for predicting behaviors, and Sherlock Holmes does this all the time when solving mysteries. By knowing behaviors, Sherlock is able to rule out certain types of people for being suspects, and when typical routines are broken, which indicate that something is afoot.

What Does Deductive Reasoning Look Like?

Seeing examples of deductive reasoning can help you give you a better understanding of how the process works, especially if you’re just developing your Sherlock deduction skills. If you’ve been asking yourself, “What is a deductive reasoning example?” check out the list below for some ideas:

  • Numbers that end in 0 or 5 can be divided by 5. The number 30 ends with a 0, so it is therefore divisible by 5.
  • Redwood trees are plants, and all plants perform photosynthesis. So we can conclude that redwood trees also perform photosynthesis.
  • Noble gases are stable. Since helium is a noble gas, we know that helium is stable.

Why is deductive reasoning used? If you don’t know whether a large number is divisible by 3, 5, or 9, but you do know the divisibility tests for those numbers, you can apply the test.

  • Is 8,910 divisible by 9? If the digits in a number add up to 9 or a multiple of 9, it is divisible by 9. The digits in 8,910 add up to 18, so it is divisible by 9.
  • 8,910 ends in a 0, which means it’s also divisible by 5.
  • 9 is a multiple of 3, so 8,910 is also divisible by 3 as well.

Deductive reasoning allows us to apply principles we know to things we don’t know, expanding our knowledge and providing answers.

Using Deductive Reasoning

Now that you better understand what deductive reasoning is, it’s time to figure out how to apply it to your own world. But how can deductive reasoning be used in everyday life?

While it may seem impossible to become like Sherlock using deductive reasoning in daily life, there are some easy ways to apply it. Whether you are a forensic scientist, doing accounting for your business, or simply want to become more observant, check out these six tips on how to develop deductive reasoning.


Many people will tell you things that seem to be true, but don’t be fooled into believing everything you hear. Deductive reasoning all about controlling your emotions and listening to reason. Sherlock seldomly lets his emotions drive his conclusions and searches for data.


It is all about observation. If you analyze and think things out, you will be more likely to deduce the right answer to things. Always take the time to look at things a second time. Try looking at things from a different angle if you’re getting stuck.

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Sometimes the easiest answer is the right one. Rather than creating larger-than-life problems, it is important to break them down, piece by piece, until we can determine what the problem really is. In calculus it’s called factoring, and it is a very efficient way of taking things apart to save time and effort. Dr. Watson is consistently surprised at the simplicity of Holmes’ deductive pathways.


Curiosity is really just the will to know and understand something as a whole. If you don’t have that then you won’t be able to motivate yourself to deduce things. Often curiosity is the catalyst behind truly important discoveries. When Sherlock is perplexed, he will keep searching for answers, because his initial result isn’t fully satisfying.


Make sure when you get those powerful feelings that you pay heed to them. Your body sometimes is smarter than your mind. There are subtle cues we subconsciously can pick up on, and oftentimes, we won’t realize it until later. Sherlock has learned to bring these cues to his conscious mind and deduce fairly accurate information about people.


By talking things out you are able to dissect and understand things more fully. Sometimes, Sherlock doesn’t have the answer until Watson provides a question he hadn’t considered. This starts a new train of thought, and helps solve a case. It’s important to remember that other people’s thoughts and opinions can help shape your answers.

Overall, learning how to develop deductive reasoning skills can help you problem solve and give you added perception as you go through life. Whether you are a student or entrepreneur, use these tips to become more like Sherlock Holmes and become a more effective problem solver.

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