““Come now, and let us reason together,” Says the LORD, ” (Isaiah 1:18a, NASB95)

Sound Logic and Flawed Logic

The discipline of logic provides a powerful framework for reasoning. The tools of logic can be very helpful in understanding and analyzing thought. One can spend a career constructing intricate scaffolding allowing the understanding of the highest of thoughts. To our great benefit, many great minds have pondered these thoughts before we came along. Their effort and dedication is an advantage to all who appreciate sound thinking and clear thought. Even for those of us who are not philosophers and theologians, the benefits of the discipline of logic are available and accessible.

Just as proper grammar facilitates clear communication, sound logic facilitates clear thought. The primary goal of disciplines like logic, philosophy or theology is not well-built framework for understanding — it is correct understanding. In the case of theology it is about a correct understanding of truths of God and of God Himself. The purpose of considering these principles is facilitation of reasoned discussion and analysis. With practice, the tools of logic should become incidental. The shovel is not important, what is important and of consequence is the size of the pile of dirt produced by the shovel (hopefully it is dirt).

Any proficient editor of grammar can read any writing and find errors or inefficiencies in how the english language was constructed. Likewise, any practiced logician, philosopher, or theologian, can no doubt find errors or inefficiencies in the reasoning or argument of another. The purpose of reviewing or introducing the concepts of traditional logic is to facilitate thinking and communication of reasoning and thought. Logic is a means, not an end. Discussion of godly knowledge, truth, and wisdom is this blog’s goal. Whether this comes from study and analysis or as a gift from above, the goal is the same.

A fault of blind dogmatism, only considering one side of the argument worth investigating, is that it stymies reasonable dialogue. Often it is not necessary for the reasonable arguer to show that an argument he criticizes is fallacious, logically inconsistent, or based on error and worthless evidence and reasoning. In fact, often strong refutation is not appropriate. Often the job of a critic can be accomplished by showing that an argument is open to reasonable doubt or lacks needed support and is open to questioning. This weaker form of criticism is very often enough to reserve or withdraw commitment to a given position.

One may believe that true wisdom comes only as a gift from God. Even from that perspective, these concepts can be still be considered valuable for man in preparing the container of his mind, heart, and spirit for receiving that blessing from above.

With this background the following information is presented for use in tackling issues in this blog.

Common Errors in Logic, Analysis, and Argument

The construction of logical arguments can be viewed as links of a chain. If one link is weak or broken, the entire chain is compromised. Errors in logic can be obvious or subtle. The term fallacy is generally used to mean an argument that is problematic for any reason, whether it is formal or informal. A formal fallacy is a form of reasoning that is always wrong. The flaw is in the logical structure of the argument which renders the argument invalid. A formal fallacy is contrasted with an informal fallacy, which may have a valid logical form and is unsound because one or more premises are false. Key errors are outlined below:

1. Types of Formal Fallacies:
   1. Bad Reasons Fallacy (your reasoning is bad therefor mine is good)
   2. Existential Fallacy (subtype of Quantification Logic Fallacy)
   3. Fallacy Fallacy (subtype of Bad Reasons Fallacy)
   4. Masked Man Fallacy (illicit substitution of identicals)
   5. Modal Logic Fallacy (possibility/necessity, temporal [past/future], obligatory/permissive, knowledge/belief)
   6. Probabilistic Fallacy (historically and traditionally categorized with informal fallacies, dependent on knowledge of probability theory)
   7. Propositional Logic Fallacy (or, not, only, if)
   8. Quantification Logic Fallacy (All/Some)
   9. Syllogistic Fallacy (non-valid combination of premises and conclusion)
2. Informal Fallacies:
   1. Personal Attack (ad hominem) — a personal attack on a person in argument. Generally, questions regarding character, motive, trustworthiness of the person
   2. Straw Man Fallacy — misrepresentation, exaggeration, misquotes, or otherwise distorting views of others
   3. Circular Reasoning (petitio principii), also called begging the question — the conclusion to be proved is already presupposed by the premises of the arguer
   4. Vagueness and Ambiguity of terms
   5. Fallacy of Equivocation — shifting meanings of a term in the same argument (often context or relativity related issues)
   6. Fallacy of Composition/Fallacy of Division — attributes of some parts to attributes of a whole or all parts of a group/or the opposite
   7. inductive or Incorrect Statistical Reasoning (post hoc, ergo propter hoc) — assigning casual conclusion on statistical correlation between two events
   8. Complex Questions (plurium interrogationum, a question that has a presupposition that is complex)
   9. Irrelevant Conclusion (ignoratio elenchi)
   10. Ignoring the Issue  (ignoratio elenchi)
   11. Appeal to Force (ad baculum)
   12. Appeal to Pity (ad misericordiam)
   13. Appeal to Emotions, popular feelings (ad populum)
   14. Appeal to Modesty (ad verecundiam)
   15. Argument from Ignorance (ad ignorantiam)
   16. Slippery Slope Fallacy
3. Fallacy vs blunder:  Systematic deception or error generally fall under the banner of fallacy. A blunder can be applied for errors that are not systematic or clever deceptions designed to make a point.