Frames of Reference

Understanding Logic and Reason

Reason and logic are two closely related forms of thinking that can be studied in terms of mathematics or philosophy and can be considered together as well as apart.[1][2]

Although these two terms are different, they have the same general end, which is truth and understanding (where logic tends to seek absolute truth and reason tends to seek probable truth and understanding).

Given their relation and the sea of definitions from 300’s BC to today, I’m not going to offer a specific answer, rather I’m going to offer many examples of the ways in which logic and reason relate and differ.

Before we get started here are the Wikipedia definitions:

  • Reason is the capacity for consciously making sense of things, applying logic, establishing and verifying facts, and changing or justifying practices, institutions, and beliefs based on new or existing information. It is closely associated with such characteristically human activities as philosophy, science, language, mathematics, and art and is normally considered to be a definitive characteristic of human nature. Reason, or an aspect of it, is sometimes referred to as rationality.
  • Logic is generally held to consist of the systematic study of the form of arguments. A valid argument is one where there is a specific relation of logical support between the assumptions of the argument and its conclusion. (In ordinary discourse, the conclusion of such an argument may be signified by words like therefore, hence, ergo and so on.)

In words, Reason is what makes us human, logic is what we often use to reason, both are modes of human thinking, but (cognitive AI aside) only logic can be mimicked by a modern machine.

Logic vs. Reason

With the above definitions in mind, the first thing to know about logic and reason is… that I’ve never seen the terms logic and reason defined perfectly.

With that said, certainly, logic is the A+B=C science one (it is a formal system with clear rule-sets), and reason is the more broad and loose “art of critical thinking” that uses logic as one of its tools (it is a more informal system of induction, deduction, and associating that mixes in beliefs, opinions, and facts and rationalizes toward many ends).

Orators and philosophers use reason liberally, while the insurance adjuster generally sticks to logic.

There are correct ways to reason (valid vs. invalid, sound and unsound), but the system has somewhat loose bounds beyond this… meanwhile logic demands rules so exact that a computer could follow them flawlessly.[3]

Logic is more a thing of the empirical, reason more theoretical. Logic is more a natural science, reason well suited for moral philosophy. A skeptic uses reason to deduce a range of probable answers, logic is binary.

Reason uses logic, but logic doesn’t have much need for reason after the rule-set has been formulated.

Reason is more like the human brain, pulling from experince, logic, ethics, morals, and tastes, considering many complex layers, associating and combing ideas, and logic is more like the cold and hard mathematics of a calculator.

With that in mind, Reason is more a thing of philosophy and critical thinking that moves one toward understanding of any sort, it can follow logical rule-sets, but can also use beliefs and opinions, it seeks truth and understanding over consistent answers (and can even be used to sway opinions, such as in oration and rhetoric).

A debater reasons, a lawyer reasons, and a person reasons with their friend to get them to share their cake.

Those who reason almost always use an assortment of different types of logic in their reasoning.

Logic is more a science that involves a series of judgments that includes formal logic like that used in mathematics and computing, and deductive logic (where conclusions are drawn from premisses).

A computer uses logic, a statistician uses logic, and a person reasoning often uses logic in their reasoning.

So, one would use logic to program a computer, but one might use reason to come up with easier ways to program the computer.

It makes sense to use logic in your reasoning, but logic itself doesn’t always require the use of reason.

In this sense we can say reason is a broad category of thinking, where logic is the aspect of thinking that can be translated to actionable and consistent rule-sets.

Consider, Deductive Reasoning and Deductive Logic are both the same thing, both are the process of reasoning from one or more statements (premises) to reach a logically certain conclusion (AKA syllogism).

Consider the classic example of a deductive argument:

  1. All men are mortal.
  2. Socrates is a man.
  3. Therefore, Socrates is mortal

In other words, there is logic to the above line of reasoning, it is a consistent rule-set (so it is logic), but it is reasoning because one is deducing information using their reason.

To frame this another way:

Logic is a science that uses defined rule-sets that produce consistent answers, reason is an art that describes all forms of critical thinking which seek understanding.[4][5][6][7]

Both seek understanding, but logic is what makes a computer run, while reason is what made Jobs and Woz decide to build computers.

One doesn’t use reason to do their math homework, they reason with their mother to stay home from school.

One might use logic in a debate, but the art of rhetoric can sometimes involve using reason and not logic.

  • Thus, Reason generally uses logic, although it doesn’t have to (one can use specific rule-sets in their reasoning such as because A is true, therefore B is also true; but they can also say, “knowing B is true, how can I use this to convince a person of C”).
  • Meanwhile, logic doesn’t generally require reasoning (as finding “X” in the equation 1+X=2 requires nothing more than a rule-set).

ON LOGIC: A master of logic was Lewis Carrol (the guy who wrote Alice in Wonderland). Alice is actually a story poking fun at theoretical mathematics and almost all of his works are about logic. If you like your brain, you’ll love having it destroyed by Lewis’ “so far from Alice it stops being funny pretty quickly, and then becomes fun again” Symbolic Logic. The more logic you know, the better you’ll be able to reason, so if Carrol’s name isn’t reason enough… I mean, logically speaking. Ok, maybe that didn’t sell you, but if that is overwhelming try a System of Logic, Ratiocinative and Inductive by John Stuart Mill (it is even more burly and will make you appreciate Carrol). Sorry, bad joke. Do read those, but start with Carrol’s Game of Logic (there is cake!) If you understand logic, you understand reason, reason is logic and then everything left over pertaining to critical thinking.

How to Argue – Philosophical Reasoning: Crash Course Philosophy #2

Reason can be used to seek any truth or understanding, but its inputs aren’t limited to facts and rule-sets. One can reason using emotions, opinions, or beliefs, and can arrive at illogical answers.

Reason is a process of critical thinking, but the result doesn’t define it.

For example, I can say, “I believe in Santa, and I want Santa to get me a unicorn, and I have only enough ingredients to make chocolate chip or blueberry cookies, since I don’t think Santa’s reindeer like chocolate, I’ll make the blueberry cookies.”

That line of reasoning is actually valid, even though nothing in the story is fact-based.

We can say the line of reasoning was “logical,” as it followed a rule-set… but I certainly would describe it as logic.

Meanwhile, if I say, “I believe in Santa, and I want Santa to get me a unicorn, so I’m going to go steal stuff…” that reasoning is not very good. Santa doesn’t get bad kids presents, so stealing stuff is not (logically speaking) going to net one a Unicorn. In other words, my logic was off in my reasoning, so my reasoning was not good.

Logic and reason are both things of pure reason, but where logic deals with formal rule-sets most often applied to the natural sciences, reason can pull from anything and be applied to anything.

So, while the distinctions are somewhat semantic in every day language, there is a world of difference between the formal science of logic (which can make a computer run), and the more ethereal art of reasoning (which is what Google tries to get its search engines to do with endless lines of coded logic when you ask it “what is the difference between reason and logic”).

All the Enlightenment founders used reason, but Newton’s mathematics are a thing of logic. We can apply reason, even when we don’t know all the facts logically.

To end, I’d say this:

  • Logic is the science of following a rule-set that produces consistent results.
  • Reason is the application of “pure logic,” empirical evidence, experiment, and skepticism to find truths, facts, and theories (AKA “critical thinking”).
  • Enlightenment is simply the natural conclusions to which reason leads.

In other words, if the goal is enlightenment, the foundation must start with logic.

TIP: Logic and reason are also music programs. Great ones actually. In music, learning the intervals and chords and scales is a thing of logic, but improvising with those rule-sets is a thing of reason. 😀

Logic –The Structure of Reason (Great Ideas of Philosophy)


  1. Reason
  2. Logic
  3. Validity and Invalidity, Soundness and Unsoundness
  4. What is the difference between logic and reason?
  5. What is Kant’s argument about the relationship between logic and reason?
  6. Logic
  7. Classical Logic

"What is the Difference Between Logic and Reason?" is tagged with: Liberalism

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