Pennington Publishing Blog

A basic understanding of logic is necessary to be able to read critically and write with coherence. Good critical thinking follow rules of logic to observe, interpret, apply, and revise ideas or problems. These rules of logic are not new. In fact, five key forms of logic were developed by the Ancient Greeks. We still use these patterns of thinking, known as reasoning, to solve problems today. Students need to be trained to recognize these patterns of logical organization and follow these patterns in their own writing and problem-solving.

1. Deductive Logic

In deductive reasoning, the pattern of thinking is whole to part. Specific applications (or conclusions) are made from general statements or accepted ideas.

Example: Bees sting. Bee stings hurt. Be careful of bees.

2. Inductive Logic

In inductive reasoning, the pattern of thinking is part to whole. Specific applications (or conclusions) lead to more general applications.

Example: (Repeated Addition) 2 + 2 + 2 + 2 = (Multiplication) 4 x 2 = (sum) 8

3. Syllogistic Logic

In syllogistic reasoning, an application (or conclusion) about a category that is drawn from two forms of evidence that each make sense as separate categories and relate to each other.

Example: All Golden Retrievers are dogs; Calico Kelley is a Golden Retriever; therefore, Calico Kelley is a dog.

4. Comparative Logic

In comparative logic, an application (or conclusion) is drawn about a situation based on how one idea or problem is similar to previous ideas or problems. The similarities are based upon logical, historical, or statistical probability.

Example: Ian is always absent from school when it rains. It is raining today. Ian will most likely be absent today.

5. If, ____; then ____ Logic

In if-then logic, an “if” state proposes a condition or hypothesis, and the “then” provides a logical answer or solution.

Example: If A = B, and B = C; then A = C.

Unfortunately, not all writing follows these rules of logic. Teaching students to recognize errors in reasoning will promote analytical reading and improve their writing coherency.

Reading, Study Skills, Writing argument, begging the question, coherency, deductive, either-or, errors in reasoning, fallacious reasoning, if-then, inductive, logic, logical argument, Mark Pennington, proposition, reasoning, red herrings, straw man, syllogisms, writing organization