Critical thinking


Published on

Critical thinking is a difficult concept to define in clear, objective terms. This can make it a challenging objective for teachers to implement and assess. The aim of this resource is to provide teachers with some tools to help clarify and communicate what critical thinking is and how it might be implemented as a teaching method.

Published in: Education, Technology, Spiritual
  • Be the first to comment

Critical thinking

  1. 1. Thinking Critically
  2. 2. Critical thinking is...? Critical thinking is a way to think about ideas. These could be ideas you’ve come up with or ideas you’ve heard or read. It covers a range of values, skills and knowledge. What a good idea! Good ideas are based on accurate information. They can be used to make decisions that are as predictable as possible. Bad ideas can be based on information that is misleading or wrong. Making decisions using a bad idea might end up causing you to take wrong actions, or cost you more than you’re willing to pay!
  3. 3. Don’t I already think well? Your brain evolved to take in information and use it to make sense of your surroundings. However, it requires a lot of energy to do this. So your brain uses a number of shortcuts to save energy. They work well most of the time, but on some occasions it makes you more confident in an idea than you should be.
  4. 4. Brain cheats!Illusions are a result of your brain taking a shortcut.Do these horizontal parallel lines look straight to you?
  5. 5. Elements of critical thinking Critical thinking involves a variety of skills, values and knowledge. Skills are thinking processes. They can involve the ability to: • Reflect analytically • Imagine broadly • Relate to other people • Communicate clearly • Identify context and bias • Apply logic effectively and recognise the application of poor logic
  6. 6. Elements of critical thinking Knowledge: describes facts and theories such as: • The structure of logic • Measured observations • Contemporary scientific theories Values: are concepts you think are important. They can involve an appreciation of: • The diversity of ideas people can have • The right to respectfully be critical of other’s ideas • That good ideas depend on accurate information • The usefulness of logic in forming new ideas • That all people can have confidence in bad ideas
  7. 7. Activity 1 & 2: What do we value? Values are what inform our decision making. Sometimes we might put a priority on friendship, while other times it might be wealth. We might like to put a value on thinking reasonably, but sometimes our fear or our faiths and beliefs might take priority instead. Knowing how to understand our own values and those of others is important in making good decisions. Read the Activity 1 & 2 handout: ‘What do we value?’ and complete the exercises Extension: Find a newspaper article or a ‘letter to the editor’ that you disagree with. Identify what values differ between you and the article’s author.
  8. 8. Video Watch Video 1: A valuable argument
  9. 9. That’s debatable! Your parents and teachers might not like you arguing, but in critical thinking, knowing what makes for a good argument is important. An argument is a structured response to an idea that shows why you should (or shouldn’t) have confidence in it. It is made of two parts: premises and a conclusion. • Premises are ideas that are already presumed be true. • The conclusion is the idea to be accepted as true or false.
  10. 10. A valid argument An argument is valid when: a) It has a logical structure b) Its premises are accepted as true
  11. 11. Video Watch Video 2: Broken logic
  12. 12. A valid argument An argument is valid when: a) It has a logical structure b) Its premises are accepted as true Example Premise 1: Magnets attract iron Premise 2: This object is made of iron Conclusion: Magnets will attract this object Both premises are accepted as true, and the relationship between the premises and the conclusion is logical.
  13. 13. Invalid arguments Arguments can be invalid if the relationship between the premises does not lead to that conclusion. Think of mathematical equations; just as 3 + 2 does not equal 1, an incorrect relationship between premises will make a conclusion incorrect.
  14. 14. Invalid arguments Example Premise 1: Magnets attract iron Premise 2: The object in my hand is attracted to a magnet Conclusion: The object in my hand must be made of iron While premises 1 and 2 are correct, they don’t combine to produce that conclusion. In this case, the premises dont exclude the possibility that other materials are also attracted to magnets.
  15. 15. False premises Arguments can have a good logical structure but have false premises. True premises come in three varieties: • Axioms (self-evident truths, such as all squares have four sides) • Observed facts • Valid conclusions from other arguments Critical thinking involves the ability to identify how likely it is a premise is true or false.
  16. 16. Activity 3 Read the following four arguments. Three of them are invalid. Identify the invalid arguments and state whether the logic is flawed or the premises are incorrect:
  17. 17. Argument 1 Premise 1: Jack started school in June. Premise 2: Things started going missing from the change rooms in July. Conclusion: Jack is a thief.
  18. 18. Argument 2 Premise 1: Scientists rubbed nano-particles into the skin of the mice. Premise 2: The mice got cancer. Conclusion: Humans can get cancer from nano-particles.
  19. 19. Argument 3 Premise 1: Bacteria are defined as prokaryotes. Premise 2: Prokaryotes are defined as having no nucleus. Conclusion: Bacteria do not have a nucleus.
  20. 20. Argument 4 Premise 1: All teachers are female. Premise 2: Bill is a teacher. Conclusion: Bill is female.
  21. 21. AnswersArgument 1 Invalid. Premises might be true, but there are other possible reasons explaining why things started to go missing in June.Argument 2 Invalid. Premises might be true, but humans and mice aren’t the same animals, therefore logically the two premises aren’t comparable.Argument 3 Valid. Premises are true and the conclusion follows from them.Argument 4 Invalid. The structure is logical, but premise 1 is false – not all teachers are female.
  22. 22. Video Watch Video 3: The man who was made of straw
  23. 23. Activity 4 Read the following four arguments and counter arguments. Each counter argument is either off-topic, over simplified, exaggerated or subtly twisted, identify which and why you think so.
  24. 24. Argument 1 Argument: The use of nanotechnology in products comes with benefits and risks. We should continue research in nanotechnology so we can understand what is safe and what is not. Counter-Argument: Nanotechnology comes with risks, and knowing what those risks are will allow people to misuse the technology. Research into nanotechnology should be stopped.
  25. 25. Argument 2 Argument: We’re pumping more and more carbon dioxide into the air, these gases trap heat in the atmosphere, and so through our actions we are heating the planet. We must do something to reduce carbon dioxide emissions and slow global warming. Counter-Argument: Carbon dioxide is also absorbed by plants; more carbon dioxide will just mean more plants. This cancels out any concerns about global warming because the extra carbon we make won’t stay in the atmosphere.
  26. 26. Argument 3 Argument: While there are ethical concerns regarding the use the embryonic stem cells, research in this area could help improve the lives of many people. We should continue with research in this area. Counter-Argument: The world is over populated as it is. Medical research just extends lives, leading to more over population. It’s unnatural that we live so long, research in this area should be stopped.
  27. 27. Argument 4 Argument: In law, a patent protects people’s work by giving them exclusive rights to it. It costs a lot of money to isolate and identify genes, and therefore it’s only right that you can patent genes. It protects your investment. Counter-Argument: Patenting genes means owning something which is naturally occurring. Pretty soon only a handful of biotechnology companies are going to own all our genetic material. Patenting of genetic material should be stopped.
  28. 28. AnswersArgument 1: The counter-argument is overly simple.Argument 2: The counter-argument twists facts to draw its conclusion.Argument 3: The counter-argument is off topic. Ignoring the issue of ethics in embryonic stem cell research to focus on over population issues.Argument 4: The counter-argument exaggerates the issue at hand.
  29. 29. That’s debatable! Extension: Are there parts of the counter-arguments that you found you would like to agree with? How do these counter-arguments match with your values from Activity 1? Visit and follow the links to Wikipedia articles to find the arguments for and against these issues. Also view the Discussion page on each issue to follow the ongoing arguments between the writers of these articles. Now write better arguments (for or against) the arguments presented in Activity 3. Discuss with your class.
  30. 30. Social thinking Your brain is a complex organ. However it is an organ nonetheless. It evolved to work cooperatively with other brains, which means it uses thinking tools that work well in groups. The upside is that there is safety in numbers. The downside is that it produces biases. These help us cooperate with people who share our values and beliefs. But it also means we are more likely to dismiss the ideas of people who we dont like or trust, or whose values aren’t the same as ours. Unfortunately this can persuade us to overlook invalid arguments, or to dismiss valid arguments prematurely.
  31. 31. Video Watch Video 4: Getting personal
  32. 32. Social thinkingWhat sort of social factors affect our thinking?Authority: We rely on experts who spend time researching facts to cometo conclusions. Identifying informed experts amongst a range of talkingheads is a vital skill in todays world.Popularity: Ideas we hear from people we view as friends or celebritiesare more easy to accept as valid.Exclusivity: Ideas we hear from people we view as bad or our enemy aremore difficult to accept as valid.Equivalence: Everybody has an equal right to hold an opinion. But not allopinions are equally likely to prove to be right.
  33. 33. Activity 5Rank from 1 to 10 (1 being least, 10 be most) whose opinions you value.Business Executive, Government Official, Politician, TV Journalist, Blogger,Friends, Teacher, Family Members, Environmental Activist, ScientistDo these people have similar values to you?Do you consider them experts?What issues would you approach these different people about?What additional people would you add to this list?
  34. 34. Misleading patterns Our brains are good at identifying patterns in nature. Sometimes, they are too good at identifying patterns and can see things that aren’t there. In the following sequence of coin flips, which face is most likely to come up next? HHHHTHTTHHHTTTTTTHHTTTHHHTTTTTTTTT ?
  35. 35. Misleading patternsWhich of these three answers matches yours?• Either: Heads or tails are equally likely• Tails: It is having a good run• Heads: It is due to come upThe last two answers is known as the gamblers fallacy. The right answer is A.It can be difficult to appreciate how probability works. Our difficultydistinguishing what is probable from what is possible makes us identifypatterns in sequences where there are none.
  36. 36. Video Watch Video 5: The gamblers fallacy
  37. 37. Confirmation biasConfirmation bias is a tendency we have to subconsciously look forpatterns that confirm ideas we already suspect are true. This means wewill be more likely to see sequences of events or listen to arguments thatsupport our point of view.Unfortunately, if our idea is a bad one, it makes it less likely we’ll spot theflaws in our arguments.Critical thinking involves challenging our ideas. This often means askingwhat the world would look like if our argument was wrong, and lookingfor ways to disprove rather than prove our ideas.
  38. 38. Effective communicationWhile jargon, metaphors or even mathematics areoften useful in communicating ideas, they cansometimes be confusing or misleading.For example, metaphors are phrases or words thatcompare a new idea with one you already know.However they can sometimes imply unwantedmeaning.DNA is like a ‘code’ where four base chemicals arearranged in a sequence.Codes are messages intentionally written. DNA mightbe like a code, but that does not mean somebodywrote it.
  39. 39. Who argues?When is it important to be able to make a good argument?Any time you need to persuade somebody that an idea is useful in makinga decision, it needs to be supported by a logically sound argument.This is called the burden of proof. Even if you need to convince yourselfthat your own idea is reliable, you should have a good argument to back itup.
  40. 40. Precautionary principleSometimes people have to persuade others to accept the risks that comefrom their actions, such as for adopting a new technology like geneticengineering or nanotechnology. If a decision you make involves otherpeople, you have the burden of proof to convince them to accept anyrisks.This is no easy task – while our actions often have an effect on others, wedont all have the same opinion about what risks are worth taking.
  41. 41. Precautionary principlePeople can sometimes demand certainty that there be zero risk, whenapplying the precautionary principle.This is a misrepresentation of the principle though, and logically it isimpossible, for there will always be some doubt, even if an idea seemscertain. The precautionary principle not be interpreted as being about100% risk free, but about having a clear understanding of the risks andbenefits of a decision, and knowing when to proceed cautiously .
  42. 42. Video Watch Video 6: The precautionary principle
  43. 43. Activity 6: Pick your argument New technology is often viewed with caution until it becomes familiar. Given the mix of potential risks and benefits science can provide, it’s important that decisions are made using critical thinking. Read the handout titled Activity 6: ‘Pick your argument’. Discuss which arguments are valid and which are invalid.
  44. 44. Activity 7: Classroom DiscussionDiscuss the following issues with your class. 1. How safe is safe? At what point does something become safe or unsafe? If it turned out to be the case that GM food was safe and could save many people from starvation, would it have been an evil act to delay introducing it? 2. A lot of people claim we should delay action on climate change until all the science is in and we have absolute proof. Some people say the same about new technologies, such as genetic engineering, but think we should act now on climate change without waiting for absolute certainty. Can these two completely contradictory positions be equally legitimate?
  45. 45. Activity 7: Classroom Discussion 3. If new technologies were developed by a massive philanthropic organisation, rather than by multinational corporations, would this affect the merits of the technology or not? Would any philanthropic organisation be acceptable? What if the philanthropy came with – for example – religious or political strings?
  46. 46. Activity 7: Classroom Discussion 4. Here are three questions we could ask when applying the precautionary principle to a new technology: • What are the benefits that the new technology could provide – what are the risks and uncertainties associated with the technology? • What are the risks and uncertainties attached to any current ways we have of realising the same benefits using existing technologies? • Do these work? What would you suggest?