Basics Of Logical Thinking

In order to think rationally (come to a conclusion based on facts rather than emotion) you need to think in a logical manner.

There are two main ways in which this can be achieved : inductive reasoning and deductive reasoning. Let’s explore both of these thinking skills in more detail.

Thinking Skill 1 - Inductive Reasoning

Inductive reasoning is a thinking skill that involves observing something, and then forming a conclusion based upon what has been observed.

For example, 150 years ago Gregor Mendel formed his theory of heredity based upon his observation of sweet pea plant characteristics. 

His conclusion was based on observation.

Inductive reasoning is the basic method of scientific investigation, but it is also a thinking skill we use throughout our life.

For example, if you are driving in your car and it starts making a noise, you may come to the conclusion that something is wrong and so you decide to get it serviced.

Inductive Reasoning = A thinking skill that forms a conclusion based on observation.

Thinking Skill 2 – Deductive Reasoning

Deductive reasoning is a thinking skill that involves forming a conclusion which follows from a premise.

For example, deductive reasoning would involve saying something like : 

“If this happens…”, “then that will happen…”, “which means the answer is…”

Deductive reasoning is a thinking skill which involves a process of investigation, and is therefore built upon a series of arguments that ultimately allows you to make some sort of prediction.

Predicate Thinking

According to Freud there is a type of thinking that occurs at the unconscious level which is neither inductive nor deductive, he called this “predicate thinking” (also called paleological thought) and is something which is commonly used by preschool children.

Freud said that when two sentences have identical beginnings (identical predicates), the objects or people in the sentences become associated in an illogical manner.

For example,

• A BMW is driven by rich people.

• A BMW is the type of car I drive.

• Therefore I am a rich person.

In this example the conclusion seems to make sense, however it is not based on facts and is therefore not a logical argument. Just because you drive a BMW, it doesn’t mean that you are rich.

Predicate thinking is one example of how logical thinking can be lead astray, although there are many other types of logical errors that can occur.

Let’s look at some of these now.

Overgeneralisation

Overgeneralisation involves jumping to a conclusion without having all the facts to support it.

For example, if you are talking to someone and they appear rude and abrupt, you may come to the conclusion that they do not like you.

However this person may have just lost their job, and so how they reacted to you was more out of frustration rather than anything personal towards you.

Overgeneralisation is quite a common way in which logical errors can occur, and causes people to form incorrect conclusions based on incomplete information.

False Analogy

An analogy is a comparison between two things that are similar in some way. This can lead you to believe that if they are alike in one way, they must be alike in other ways.

A false analogy occurs when this comparison results in an incorrect conclusion.

For example, water is liquid and is good for you to drink. Engine oil is also liquid and must therefore be good to drink.

In this example two things have been compared which are similar in one way (liquid). The false analogy leads us to believe that they are also similar in other ways, when in fact they are not.

Appeal To Authority

An appeal to authority involves backing up a weak argument by making reference to an authority figure.

For example, you tell your friend they should eat more green vegetables. When they ask you why, you say “because the nutritionist on TV said they were good for you”.

In this case, rather than presenting factual information such as the nutritional content of green vegetables, you have chosen to back up your argument based on what someone else has said.

In other words, you didn’t really have the facts to back up your argument, so you made an “appeal to authority”.

Even though in this example the argument was correct, an appeal to authority can very easily cause you to form incorrect conclusions, especially if your source (the authority figure) is incorrect themselves.

Arguing In Circles

Arguing in circles involves making an argument that doesn’t contain any real meaning to it.

For example, you say to your friend “I like you”. They reply “why?” You say “because I really like you”, they say “why?”. You say “because you’re such a likable person”.

In this type of circular argument no factual information is given to back up a statement, and as a result your friend cannot come to any firm conclusion as to why you like them.

It would have been better to say for example, “I like you because you have a great sense of humour and make me laugh”. Now it will be possible for your friend to form a correct conclusion as to why you like them.

Attack On Character

An attack on character involves using something someone has done wrong in the past, to discredit them or their argument.

For example, John is in a debate and arguing his case, when his opponent counters by saying “John was caught stealing money at work two years ago, so you can’t trust anything he says”.

In this example John’s argument has been discredited with a reference to his past, even though his past actions have nothing to do with his speech.

Summary Of Thinking Skills

• Rational thought is based on facts not emotions.

• Inductive reasoning is a thinking skill that involves a process of forming a conclusion based upon what has been observed.

• Deductive reasoning is a thinking skill that involves an investigative process that allows a prediction to be made based on the available evidence.

• Predicate thinking is an unconscious method of thinking proposed by Freud, that does not involve inductive or deductive reasoning.

• Overgeneralisation involves forming a conclusion without examining all the facts.

• A false analogy results in a comparison between two things which share a similar property. This leads you to believe they are similar in other ways when they are not.

• An appeal to authority involves backing up a weak argument by referring to an authority figure.

• Arguing in circles is an argument that does not contain any factual information, and therefore does not allow a firm conclusion to be made.

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