Revised 16 September 2021

Critical Thinking

An argument is a presentation of reasons to support a conclusion. An argument can be verbal or in written form. 

A person who practices critical thinking can make an objective and rationale assessment of the assertions and arguments of others. By doing so, a critical thinker is better able to make decisions and solve problems than those who do not practice critical thinking. 

Critical thinking involves the ability to recognise the logical form of an argument, deconstruct that argument, and then evaluate the conclusion. Someone with a high IQ and/or who has broad knowledge and a fast memory recall is not necessarily a critical thinker. 

Critical thinking includes not only understanding the correct use of logic, but also considers the psychological biases of oneself and others. Critical thinking requires practice, effort, and the humility of being prepared to objectively consider claims and arguments of others which challenge one’s own beliefs. 

The process of critical thinking is not intended to make all people think alike and critical thinkers can come to different conclusions due to having a different value system. Actions or inaction which follow beliefs based on some value systems might  imperil the rights, wellbeing, and safety of others.  

Formal Logic

Aristotle (384 BCE – 322 BCE) developed a formal framework of deductive reasoning. The following three statements is a classic example of deductive reasoning: 

1. “All men are mortal

2. "Socrates is a man”

and then concludes

3. "Socrates is mortal" 

The above conclusion is a logically valid deduction based on reasoning from the general to the particular. 

In formal logic, the statements “All men are mortal” and “Socrates is a man” are known as premises (propositions) and a syllogism is the simplest sequence of logical premises and conclusions. The modern term "argument" will continue to be used here for any form of reasoning in which a conclusion is drawn from two or more premises. The key feature of a logically valid deduction is that if the premises are true and one thing follows necessarily from the other, then the conclusion must be true. 

Deduction alone, however, cannot establish whether a conclusion is true or not as opposed to being logically valid. All that logic can offer is that if all the premises are true, then the conclusion must also be true so long as the conclusion follows necessarily from the premises. If any of the premises is not true, then the conclusion is also not true. 

Refer to the Recommended Books Sub-section: Scientific Method and Sub-Section: Critical Thinking for the sources of this Sub-section and further reading.