Revised 26 September 2021


Critical thinking is the ability to evaluate arguments. Understanding how to construct your own valid arguments is an advantage, but not essential, in evaluating the arguments of others. The focus of this Section on Critical Thinking is on evaluating the arguments of others. Guides to constructing your own arguments are provided in the Recommended Books Section.

Deconstructing Arguments

An argument can involve multiple chains of links to support a conclusion. If a verbal argument is complex, then it is an advantage to have a recording of that argument which can be used to create a written transcription to enable deconstruction.  

Not all arguments are presented in a clear and unambiguous form. This can be deliberate confusion. Deconstruction of an argument is a process of disentangling the chain of arguments into separate sets of premises and conclusions and linking conclusions which form the premises of higher order conclusions. The total argument stands on the weakest link in the chains of reasoning. Deconstructing arguments can be done with pen and paper or by using a word processor. 

It is an advantage to set out the structure of a complex argument in graphical form. Pen and paper are adequate, but the use of graphic software makes the task easier. There are several graphics software packages or apps which can be used. For example, Simple Mind is free and Simple Mind Pro can be tailored for specifically mapping out chains of reasoning. The Rolls Royce of argument mapping software is Rationale which can be used online or on Windows desktop, both on a subscription basis. The use of Rationale greatly simplifies the task of deconstruction (or construction) of complex arguments. 

The process of deconstructing an argument involves assessing whether:

1. assumptions of an argument are warranted

2. reasoning is relevant and sufficient, 

3. relevant information has been omitted.  

Assumptions can be overt and explicit or covert. Some overt assumptions can be unrealistic. For example, many economic assumptions which underpin theory lack physical reality. Although predictions of many economic theories based on unrealistic assumptions are unsupported by empirical data, these theories have not been revised despite evidence to the contrary. These failings are addressed in the Section: Current Economic System

Covert assumptions can be the most difficult to identify. In many cases, the boundary of the subject matter is too limited and the argument has accordingly failed to address the full story. 

The ability to recognise fallacies of arguments forms a large part of assessing whether the reasoning of arguments is relevant and sufficient. A fallacy is a type of argument that may seem to be correct, but upon examination is not. Two or more different arguments can contain or commit the same fallacy. It is useful to study and recognise arguments with similar and different types of fallacies to help keep us from being misled. To be forewarned is to be forearmed.

Arguments which omit relevant evidence can appear to be stronger than they really are. Knowing immediately whether critical information has been omitted or not requires a broad background in the field of the argument. This is where the principle of “Extraordinary claims require extraordinary evidence” applies. Common sense can play a large part in identifying omissions of relevant evidence.  

Recognising Fallacies

Aristotle  (384 BCE – 322 BCE) originally identified only 13 types of fallacies. Many more fallacies have been identified over the centuries since. There is currently no universally accepted classification of fallacies. Nonetheless, some classifications are more useful than others. 

Greg Haskins wrote a 20-page paper “A Practical Guide to Critical Thinking” which was hosted on beginning in 2004. This paper was largely based on Robert Todd Carroll’s book “Becoming a Critical Thinker - A Guide for the New Millennium” published in 2000. A copy of Haskin’s paper can be downloaded here

Haskins’ paper divides hindrances to critical thinking into the following four categories:

  • Hindrances due to Basic Human Limitations
  • Hindrances due to Use of Language
  • Hindrances due to Faulty Logic or Perception
  • Hindrances due to Psychological and Sociological Pitfalls

Haskins’ paper forms the basis of his 2016 Kindle book A Practical Guide to Critical Thinking: Essential Steps for Developing Sound Reasoning and Arguments while Overcoming Hindrances to Rational Thinking. This book can be purchased for a nominal sum from Haskins has added a 5th category "Hindrances due to Natural Biases" in this book.  

The following is Haskins’ (2016) description of each category:

Basic Human Limitations

Basic Human Limitations … applies to everyone, including the most proficient critical thinkers. These limitations remind us that we are not perfect and that our understanding of facts, perceptions, memories, built-in biases, etc., precludes us from ever seeing or understanding the world with total objectivity and clarity. The best we can do is to acquire a sufficient or adequate understanding depending on the issue at hand.”

Use of Language

“The Use of Language… is highly relevant to critical thinking. The choice of words themselves can conceal the truth, mislead, confuse, or deceive us. From ads which guarantee easy weight loss to politicians assuring prosperity for everyone, a critical thinker must learn to recognize when words are not intended to commu­nicate ideas or feelings, but rather to control thought and behavior.”

Faulty Logic or Perception and Psychological and Sociological Pitfalls

“Misconceptions due to Faulty Logic or Perception (Appendix 3) or Psychological and Sociological Pitfalls … can also lead one to erroneous conclusions. A critical thinker must understand how numbers can be used to mislead; perceptions can be misinterpreted due to psychological and sociological influences; and reasoning can be twisted to gain influence and power.”

Natural Biases

Natural Biases … are hindrances which we develop over time from our own unique cognitive experiences. These experiences cause us to develop our own “rules of thumb” (or heuristic) ways of learning, doing things, approaching problems, and rendering judgments. Though cognitive, these natural biases are heavily influenced by our past emotional experiences.” 

Haskin’s paper and book are already in summary form of what is required to be a critical thinker. This web publication would serve no good purpose in providing a summary of a summary. A first step towards becoming a critical thinker is to obtain a copy of Haskin’s paper and/or Kindle book and absorb the contents. Developing critical thinking requires time, effort, and commitment. Further resources on critical thinking can be found on a sister website here