Why would I learn to think (logically)?

Most people are convinced of their ability to think logically and don’t see the point of getting a specific training like the Logical Thinking Process  training course.

Indeed, in some extend most of the people have an innate basic logical thinking way, otherwise our world would be pretty weird.

Yet it is also true that many people are unable to structure properly their thoughts and express their ideas with clarity and in a straightforward brilliant logical way. Even so it makes sense in their mind, what they try to share doesn’t always make sense to others.

How many times did you listen to someone and ask (yourself) “so what?” once the speech is over.

The importance of clarity

The first important thing to achieve is to express ideas with clarity. Clarity means that the idea, purpose, objective or goal is expressed in an unambiguous way, letting no room for misunderstanding or interpretation.

Clarity is always important. As an employee to be correctly understood by managers and colleagues and as a leader to be correctly understood by the team members or subordinates.

Imagine the consequences of an ill-stated objective. Stakeholders may misunderstand it and do something unexpected but aligned onto the objective they understood. Such kind of situation can be costly in terms of motivation – the stakeholders are feeling bad about their misunderstanding, resenting their leader for his/her poor objective statement and disappointed for all the energy they put into some action, for nothing – and in terms of resources and time wasted.

Ambiguous or ill-stated objectives are also welcome for some people to smartly escape some chores or refrain to commit to something they don’t agree, don’t want or don’t like. Room for interpretation is also room for later arguing. Something not desirable when some objectives are non negotiable.

Conversely, the inability to clearly explain what has been achieved, why and how it contributes to achieving some objective may make a team member look as a poor performer even so his/her contribution was significant.

It is frustrating to be a brilliant contributor to some project but unable to explain why and how. It is also frustrating to be unable to “sell” a brilliant idea to colleagues, the boss or customers.

Sound logic

The robustness of a cause-and-effect analysis or demonstration is also important in order to convince readers or listeners about the soundness of the ideas expressed.

According to the principles of adult learning, sense and purpose must be fully understood for adults to commit to something. If the rationale of some project or actions asked is not demonstrated in a clear and sound (robust) way, it will invite opponents to fight against it, making use of all “holes”.

Some undertaking presented in a fluffy way with many unanswered questions remaining open is scary. Opponents will have it easy to reinforce the doubts and fears of the audience by pointing out the inconsistencies and “holes” in the reasoning.

Lack of confidence is very likely to turn away customers, stakeholders or decision makers from the best of proposal. Instinctive risk aversion is probably more common than innate logical thinking.

Using “long arrows”

Many people with good logical thinking abilities will mentally cut corners and use “long arrows” in their demonstration. A long arrow is a metaphor for skipping several cause-and-effect steps linking an effect to a cause or the other way round.

While the link exists, it does not appear clearly. The audience cannot understand the rational link between an effect and a cause and may lose trust or interest about the presentation, get stuck because of this logical “hole”, doubt about the reality and validity of the ideas expressed, and so on.

Long arrow example

I have to make a presentation in building n°10, 15 minutes walking from here. It rains. I need an umbrella. I must borrow one.

“Could I borrow your umbrella because I must present my report?” I ask a colleague.

My colleague may ask herself what the link is between presenting a report and her umbrella. She will probably lend me the umbrella anyway, still not understanding what for. I did not feel necessary to explain the whole sequence of cause-and-effect, perfectly clear and logical in my head but strange when expressed that way.

Now imagine asking for commitment to something very important and serious that does not make sense because of long arrows.

Mastering logical thinking is also about avoiding long arrows and being able to detect them. I guess someone trapped with long arrows would be grateful for the help by someone seeing the shortcut and helping to reformulate the idea in a more robust and clearer way.

Mitigate the risk of “negative branches”

Negative branch is another metaphor used in the Logical Thinking Process, were logical relationships are depicting in logical trees. A negative branch is an undesirable effect or chain of cause-and-effect that “grows” from an action or decision taken.

Negative branches are often growing unexpectedly because the action was decided or decision taken without checking the possibility for things to go in an unexpected and undesirable direction.

Some fixes for a problem can result in other problems to arise, sometimes worse than the initial problem that was to be fixed.

Awareness and practice of the Logical Thinking Process hones the ability to “foresee” or at least to prevent negative branches and craft better solutions.


Basic logical thinking is a given and it may appear strange to promote “learning to think logically”. But it is as with many other things supposed to be “common” but aren’t. Common sense for instance is not so common.

Therefore there is a lot of room to improve one’s logical thinking skills.

Once introduced to the Logical Thinking Process, there are daily opportunities to hone one’s scrutinizing abilities. Newspaper, tv news, blog posts, speeches… are not always constructed with sound logic. Fallacious reasoning is easier to debunk, as well as surfacing false assumptions or “insufficient causes” on which some thinking are built upon. Negative outcome can be sensed and hopefully prevented.

Mastering Logical Thinking helps for better analyzing situations, understanding real causes of problem, crafting better solutions and expressing oneself much better.

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What are Categories of Legitimate Reservation?

Categories of Legitimate Reservation (CLR) are rules for scrutinizing the validity and logical soundness of Theory of ConstraintsThinking Processes logic trees and diagrams.

As with most of simple looking methods and tools, it is easy to get trapped or misuse the seemingly simple logical tools proposed by the Thinking Processes. In order to prevent decision making and actions based on flawed analysis, the CLR provide effective rules to check and validate the logical soundness of the various trees and diagrams.

Bill Dettmer call them “logical glue” that hold the trees together. In “The Logical Thinking Process”, Bill provides a full chapter (34 pages on the CLR).

There are eight Categories of Legitimate Reservation:

1. Clarity: is used to check the complete understanding of a word, idea or causal connection and avoid ambiguous wording. All the trees and diagrams are also good communication support, it is therefore important to insure the content is fully understood by anyone, even people not involved in the trees and diagrams construction.

2. Entity Existence verifies the reality or existence of the stated entity in the reality of the scope of analysis or problem solving. Sometimes people confuse building logical Thinking Processes trees and brainstorming, adding entities which are assumptions but not proven realities.

3. Causality Existence is the next thing to verify. Does the cause really lead to this effect? It is then important to read aloud the relationship, for example: “if A exist, then B exist” or “in order to have B, we must have A”.

4. Cause Sufficiency looks for one (set of) cause(s) to be sufficient by itself to create the effect. In complex systems, several independent causes could lead to the effect (logical OR) or some causes may combine to produce a given effect (logical AND).

If one legit cause remains hidden/unknown, the injections (solutions) may not always prevent the effect to occur. It is therefore important to list all causes.

5. Additional Cause is the check if no other cause, not mentioned so far, could have the same effect.

6. Cause-Effect Reversal checks the possible confusion between cause and effect.

7. Predicted Effect Existence is the search for an (additional expected and verifiable effect of a particular cause. Dettmer states that this reservation does not stand alone, but helps to validate or invalidate causality existence. If another predictable effect appears with this cause, the cause exists. If the additional effect does not show, the cause existence is very likely invalid.

8. Tautology, also called circular logic, is checking if the effect is not the sole and insufficient proof or rationale offered for the cause existence. It happens mostly when the cause is intangible: I strongly hopped for good weather ==> the weather was good because I strongly hopped for it.

“Long arrows”

Looking for “long arrows” is not formally part of the CLRs but I see it as such.

Long arrows are logical relationships linking causes to effects skipping multiple intermediate cause-and-effects, usually because the analysts know the intermediate links and do not feel necessary to describe them.

The risk of long arrows is to confuse people who weren’t involved in the tree building and/or are not sufficient familiar with the subject or situation.

Long arrows may also appear as flaws in the tree construction, thus making people reading them or attending a presentation doubt about the robustness and soundness of the whole.

The only acceptable long arrows, which are purposely used, are for Executive Summary Trees. And in this case, some caution is advised.

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