Explore all our learning and teaching solutions

Explore all our learning and teaching solutions

Got a Kanye-sized ego? → Test it on our Ego-Meter
Logic Introduction

Logic Introduction

  • Report
Author: Jacob Sorem
  • Define a Syllogism
  • Define Deductive and Inductive reasoning
  • Define a Logical Fallacy
See More


The structure of the logical syllogism involves premise statements and a conclusion. Generally, syllogisms are made up of three statements (two premises and a conclusion). In those three statements, there are three concepts that are related (A, B, and C). The Syllogism then becomes:

  1. Premise: A is B
  2. Premise: C is A
  3. Conclusion: Therefore C is B

There is also a way to introduce a negative. (Note how this changes the order of the C relationship to A and B.)

  1. Premise: A is B
  2. Premise: C is not B
  3. Conclusion: Therefore C is not A.

The following videos give further explanations as well as examples.

Deductive and Inductive Reasoning

Application: Finding Logical Arguments in an Article

Article link used in the video:


Appliation: Identifying Logical Fallacy in an Article

Article link used in video:


Questions and Answers

  • Tikvah
    Answer 1
    Tikvah — over 2 years ago

    Generally speaking, what is the academic definition of deductive reasoning? There seems to be multiple platforms to use deductive reasoning (ex. solving puzzles) or to analyze and create logical arguments, but I don't think I'm fully understanding what deductive reasoning is in a broader, general sense. Furthermore, what are some examples of deductive reasoning techniques that can be applied to any situation?

      Jacob Sorem answered over 2 years ago

      Deductive reasoning is the act of using clues to find an answer that might not otherwise be apparent. There's a quote from Star Trek VI that Spock said that pretty much sums up what deductive reasoning is all about: "if you eliminate the impossible, whatever remains, however improbable, must be the truth" (which is also very close to what Sherlock Holmes says in the Sir Arthur Conan Doyle stories).

      In a practical sense, we use deductive reasoning to problem solve. We try something; if it doesn't work, we try something else. Every time we try something, we can eliminate that something as either the answer we are looking for or not. Theoretically, we could systematically assemble a jigsaw puzzle by trying each piece with every other piece. We will eventually get the finished puzzle in this manner, without ever looking at the picture. That might be the ultimate use of deductive reasoning.

      Tying this concept to IT Support and Troubleshooting, if we have a problem like no picture on a computer monitor, we can identify possible solutions and then try each one. Is the power switch on? Are all the cables plugged in? Does another monitor work with this computer? Does this monitor work on another computer? Answers to each of these questions can help us narrow down to the eventual solution. That's deductive reasoning.

      In my class, we use the logic puzzles and games to help hone deductive reasoning. It doesn't come easy for everybody, and the more you practice it, the more intuitive it becomes.

      (Great question!!)

College Algebra

Do the math.
Our College Algebra Course is only $329.

Sophia's online courses not only save you money, but credits are also eligible for transfer to over 2,000 colleges and universities.*