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Critical Thinking

Updated: Jan 2, 2021

Thinking is extremely important for how we make decisions, know what to believe, and how we understand the world around us. Critical thinking is one's ability to assess and evaluate the legitimacy of beliefs, claims, theories and evidence. Logic and reason is fundamentally based on how our statements relate to one another. An argument exists when some statements support the truth of another statement like, 'I am very tired and I need to rest. I see a chair in the corner so I will take a moment to sit on the chair.' The decision to sit in the chair made is based on several statements, some assumed and others explicit.

There are much more complicated decisions and beliefs we face every day. It is in our best interest to have a deep understanding of how to measure the integrity of our beliefs and decisions. To make sense of the statements and things in our mind we can develop our critical thinking skills. We can also use critical thinking to reduce or eliminate the amount of cognitive distortions that could lead to emotional suffering as seen in the Feeling Good Tool and Burns' CBT research.

Critical thinking is a structured form of thought that offers predictable results. Critical thinking is founded on our skills at building reason-based thoughts with the use of evidence, an awareness of valid argument forms, and an understanding of logical fallacies.

Arguments built of premises supporting conclusions are like the relationship between the legs of a table supporting the table top. The table top or conclusion, is supported by the legs or the premises. If the table, the argument, is constructed properly, the legs, premises, will support the table top, the conclusion.

If the legs are illusionary, premises that are not true, then the table will not even support itself and fall. If the table legs, premises, are not connected correctly, invalidity, they will not support the table top, the conclusion. Arguments or the reasoning process is very much like the structure of a table. If our premises or evidence does not support the conclusion, our reasoning fails. If we construct our arguments correctly, the premises will support our conclusions.

There are two primary types of reasoning: deductive and inductive. Deductive reasoning occurs when we think from general to specific statements, like 'all chairs can be sat on, I can sit on this chair.' When reasoning deductively, if we are able to have true premises, we will always have a true conclusion.

Inductive reasoning goes in the opposite direction, from specific details to general claims. An example of inductive reasoning would be, 'Every cat I have seen has 1 thumb. Xanadu is a cat therefore he has 1 thumb.' This argument is actually not true. For if you ever meet Xanadu, you will notice that he has mitten paws; a genetic variation where he has 2 thumbs! Inductive arguments can only be probably true for they reason from specific observations to general categorical claims.


Deductive Validity

Validity is a term used to describe the structure of an argument. If the structure of our deductive reasoning is valid and we have true premises, our conclusion will always be true. If our premises are true, but our reasoning is invalid, then even if the conclusion is true we did not prove or support the truth of the conclusion. The invalid structure of those premises does not prove the truth of the conclusion. A valid structure with true premises will always yield a true conclusion and a sound argument.

We can identify valid and invalid arguments based on their structure. I will offer both deductively valid and invalid argument types here. If we have the correct structure, we simply have to plug in true statements into the premises and we will always have a true conclusion. If we recognize that the structure resembles an invalid form, we know to restructure our reasoning so it can be sound.


Valid Arguments:

1. Affirming the Antecedent (Modus Ponens)

If P then Q

P

Therefore, Q.


If you have the key, you can unlock the door.

You have the key.

Therefore, you can unlock the door.


2. Denying the Antecedent (Modus Tollens)

If P then Q

Not Q

Therefore, not P.


If there is smoke, then there is fire.

There is no fire.

Therefore there is no smoke.


3. Hypothetical Syllogism

If P then Q.

If Q then R.

Therefore, if P then R.


If I run, I will get exercise.

If I get exercise, then I will reduce my stress.

If I run, I will reduce my stress.


4. Disjunctive Syllogism

Either P or Q.

Not P.

Therefore, Q.


Either I develop my critical thinking skills or it will be difficult to know what is reasonable.

I didn't develop my critical thinking skills.

Therefore, it will be difficult to know what's reasonable.


Invalid Arguments:

1. Denying the Antecedent

If P then Q.

Not P.

Therefore, not Q.


If it is an animal, then it has legs.

It is not an animal.

Therefore, it does not have legs.


2. Affirming the Consequent

If P then Q.

Q.

Therefore, P.


If I am a man then I am human.

I am human.

Therefore, I am a man.


It takes time and practice to recognize these patterns of reasoning. The benefit of learning these structures will help you better understand yourself and communicate your ideas to others more effectively. There are times when emotions run high or when we are under a lot of stress. It is in these times where our training in critical thinking is very beneficial when developed into a habit.


Inductively Strong Arguments and Fallacies:

Inductive arguments do not follow the same pattern as deductively valid ones. Inductive arguments, which are based on probability, can be more or less likely; strong or weak. One important strategy for assessing the integrity of inductive arguments is to determine if there are any flaws in the reasoning due to committing a fallacy.

There are three types of fallacies: unacceptable premises, where the premise itself is very questionable, irrelevant premises, the premises has nothing to do with the argument being presented, and insufficient premises, where the premises does not support the likelihood of its conclusion.

Most arguments we come across are inductive because people work with the observations they have available to them and try to make a general understanding from those observations. Becoming familiar with the informal fallacies can greatly enhance one's ability to detect issues in our own and others reasoning.


Unacceptable or Presumptious

1. Begging the Question

When the conclusion in an argument is being used as a premise, the reasoner is engaged in circular reasoning. The individual is assuming the very thing that they are trying to prove by simply rewording the claim differently not providing any new justification for the claim.

Ex: 'Ghosts are real because paranormal activity occurs all the time.'


2. False Dichotomy or False Dilemma

This reasoning flaw occurs when the reasoner provides only two alternatives when there are actually more possibilities. Not taking into account the other possibilities and framing the reasoning to exclude them creates a fallacious argument.

Ex: 'Only two choices exist, work as a cook or become a carpenter!"


Irrelevance

1. Appeal to Force/ Fear

A person in a position of power uses threats to coerce a person to accepting a conclusion.

Ex: 'I am right! If you do not agree, your fired!'


2. Appeal to Pity

A person attempts to evoke sympathy from an audience to gain support for their conclusion by focusing on the distressing nature of the speaker.

Ex: 'Please give me money to go out with my friends. I am very upset about failing my exam.'


3. Appeal to Emotion

The argument uses emotionally charged language to persuade the audience that the conclusion is true.

Ex: 'Climate change is a real threat. Are you willing to risk the beautiful, lush oceans, deep green forests, and fuzzy friendly animals?'


4. Appeal to Authority

The argument uses social rank as a method to prove the truth of the conclusion. An appeal to an expert is only valid if the person is actually a master of their field.

Ex: 'My favorite hip-hop artist says that sugar can actually prevent cancer!'


5. Ad Hominum/ Appeal to the Person

The argument focuses on attacking the character of the individual to illegitimize the claims the individual is making. To know if something is reasonable, we have to assess the reasons for saying it, not the integrity of the person.

Ex: 'The leader of our country is an asshole. I don't care if he supports social programs or not, everything he says is wrong.'


6. Appeal to Ignorance

The lack of proof is not proof. It is the attempt to argue something is true because has not been proven false or that something is false because it has not been proven true. Our ignorance of a thing cannot make it true or false. We cannot prove a universal negative, meaning one cannot go into the cosmos and check if somethings isn't there, everywhere.

Ex: 'We have no proof of aliens therefore they don't exist.' or 'You can't prove Santa Claus exists, therefore he does.'


7. Composition

When someone reasons that what is true of the parts is also true of the whole. The whole may be greater than the sum of its parts, meaning that the whole has a property that single a part do not. The kind of property that wholes have that the parts do not share is called an emergent property. Some arguments from parts to wholes may be true, but only if the parts and wholes share those properties. The issue falls in making an assumption that the parts and whole necessarily share properties.

Ex: 'I totally love mustard, ice cream and pickled eggs, therefore making a shake out of them would be awesome!'


8. Division

When someone assumes the properties of the whole necessarily apply to the parts.

Ex: 'Water is wet, therefore the water molecules are wet as well.'


9. Equivocation

When we use a word that has two different meanings or senses in an argument, we have committed a fallacy. The different interpretations in meaning reduce the strength of the argument or reasoning.

Ex: 'Man is a great being. Man is greater than woman.'


10. Genetic Fallacy

When someone reasons that the cause or origin of the claim determines the truth or falsity of the claim. It does not matter how the reasoner came to the argument for us to determine the legitimacy of its truth. We must assess and evaluate the reasons independent of how the thinker came to it. We must assess the evidence and structure of the argument to determine its truth.

Ex: 'That idea sucks, you thought about it while you were drunk.'


11. Appeal to the Masses

Just because the majority of people believe something does not make it true.

Ex: 'Everyone hates the kid in the corner, so he is probably a bad guy.'


12. Straw Man

When someone misrepresents your claim as a weak representation and attacks the inaccurate claim to refute, it is fallacious reasoning. The misrepresentation is not relevant to the issue initially raised.

Ex: 'Abortion for a tubal pregnancy is still killing the fetus and killing is murder. You are advocating murder and murderers are wrong.'


13. Red Herring

When a person intentionally diverts attention away from the initial argument to an alternative argument they are prepared to discuss or defend.

Ex: Person 1: 'Hey man, did you forget to clean the table?'

Person 2: 'Oh, don't you owe me 5$?'


Insufficient

1. Hasty Generalization

When a conclusion is made about a general category from a small number of things within that category it is fallacious. The sample that the generalization is being made from must be representative of the group for the generalization to be reasonable.

Ex: 'You slept in this morning therefore you are a lazy person.'


2. Faulty Analogy

The problem when using analogies in reasoning exists if the thing being compared do not share the relevant properties the reasoning implies. The reasoning must account for the degree of similarities and have low or insignificant dissimilarities or the argument is fallacious.

Ex: 'Driving a car is just like riding your bike. Both get you where you want to go.'


3. Correlation Causation/ False Cause

The assumption that when two events occur at the same time one of them caused the other to occur. Correlation does not prove causation.

Ex: 'I heard thunder and the lights in the living room went off!'


4. Slippery Slope

When someone reasons that one action will lead to a single or series of negative actions and thus the first action ought not be taken they are engaging in is a fallacy. The chain of reasoning is only legitimate if there is good evidence to support the sequence of events.

Ex: 'If you go out of the house you will be closer to danger. It's a big city and people get shot so you could be shot. I don't think you should leave the house.'


As you can see there is quite a bit of information to learn to develop critical thinking. Critical thinking is taught in universities as first and second year courses and it would be beneficial to anyone to take some of these courses.

It is very important to learn how to understand our thoughts and make sense of them. If we can develop a rational construction of our ideas, we not only can understand ourselves but communicate effectively to others as well.


AJ 8.2.18, 26.2.18, 14.3.18, 29.5.18, 16.8.18, 23.8.18, 27.3.20


Amazon Link to Schick and Vaughn's 'How to Think About Weird Things':

https://www.amazon.ca/How-Think-About-Weird-Things/dp/0078038367/ref=dp_ob_title_bk

ISBN: 978-0-07-353577-7


© Achilles Atlas Justice and achillesjustice.com, 2018 - 2021. Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Achilles Atlas Justice and achillesjustice.com with appropriate and specific direction to the original content.

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