Class 7 - Jan. 27, 2026

Underlying assumptions

• Suppositions upon which an argument is based
  • "What must we believe if we are to see the evidence as relevant to the claim being made"
• They're usually implicit or unstated
• You can deduce what they are by reading the text
• Helps us understand if the premises and evidence build the claim

Why are assumptions underlying?

• Generally, author believes reader holds the same assumptions
  • Why?
    • They're often deeply engrained in us and part of our belief system
    • Often taken for granted
    • We often don't even notice them
    • It would be tedious to spell them out every time
  • Implications
    • Different people may have different assumptions - must be careful the assumptions you are using won't influence the persuasiveness of the argument
    • If underlying assumptions are questionable, argument may be weakened even if it includes quality evidence
      • But you must be self-aware of those underlying assumptions and that they could be questionable

How do you find underlying assumptions?

Ask these questions:

1. What must be true if the claim is to follow from this evidence?
2. What general principle might link this claim to this evidence?
3. What beliefs might I expect from the author?
   • Being open-minded and open to new perspectives
4. Could someone believe this evidence and still not accept the claim? Why?

Two types of underlying assumptions

1. Reality assumptions
   • "The way things are"
   • Beliefs about what events have taken place, what exists, how thinks work in the world
   • Shaped by first-hand experiences, conversations, what we read / see
   • How to evaluate the accuracy of a reality assumption
     • Use data / provide new information
2. Value assumptions
   • "The way things should be"
   • Ideals, standards of right and wrong, the way things SHOULD be
   • Shaped by family, teachers, friends, religion, culture
   • Often resistant to change
   • How to evaluate the accuracy of a value assumption
     • We can't
     • They're values for a reason

Sample Argument - Free University Tuition in Canada

Claim: University tuition should be free in Canada

• Premise: It increases access to higher education and creates a more equitable society
  • Assumptions:
    • Free tuition increases # of students enrolling
      • Reality - test by comparing rates in countries with free tuition (pre and post)
    • Governments should take actions that increase equity among citizens
      • Value - n/a
    • There's a large amount of people that want to go to university but can't afford it (cost being a main barrier)
      • A different way of saying this: the primary barrier to enrolling in university is the cost of tuition
      • Reality - test by surveying young people to determine reasons for not enrolling
    • Higher education dries equity in society more than other measures / opportunity cost of providing free tuition is less than other options
      • Reality - test by comparing equity levels in countries where tuition is free
    • Free tuition increases the number of people graduating
      • Reality - test by comparing graduation rates in countries where tuition is free (pre and post)
    • Universities in Canada have the capacity for more students
      • Reality - test by surveying university administrators to determine capacity levels
• Premise: It benefits the economy as an educated workforce drives innovation, productivity, and economic growth
  • Assumptions:
    • Innovation, productivity, and economic growth is generated more by university graduates than other types of employees
      • Reality - test using economic output data by education level of employee
    • University graduates that don't pay tuition enter the workforce sooner than other workforce entry paths
      • Reality - test by gathering data on workforce entry paths
    • Students gain same skills in free tuition environment / quality of university education is unchanged
      • Reality - test by comparing quality levels of countries who have free tuition
    • Canadian government can afford to pay for tuition completely
      • Reality - test by financial analysis of federal government
    • Benefits to economic output outweigh the cost of providing free tuition
      • Reality - test using cost/benefit analysis
    • University graduates who don't pay tuition will stay in Canada
      • Reality - test other countries who have free tuition to see if they stayed in the country
    • Free tuition does not change length of time to finish degree
      • Reality - test other countries who have free tuition to have check time it takes to finish
    • Employers do not change their entry-level job requirements
      • Reality - test pre and post entry-level job requirements
    • Canadian economy has capacity for more educated workers
      • Reality - test using unemployment rates
• Premise: Students can graduate without the burden of debt, which means they will contribute positively to the economy sooner
  • Assumptions:
    • Students don't have many other expenses during their time at university / The primary source of debt is tuition
      • Reality - test by researching sources of debt of university students
    • Governments should support the well-being of young citizens
      • Value - n/a
    • The sole reason grads don't contribute to economy sooner is debt from tuition
      • Reality - test by
    • Canadians do not pay more tax even when university tuition is free
      • Reality -

Identifying & Evaluating Assumptions is a lot of work - why bother?

• Helps us determine if we feel comfortable accepting the argument
• Look at the assumptions that would have to be measures to make sure it's a valid argument
• Use questionable assumptions as red flags
• How can you transfer this skill of uncovering, classifying, and evaluating assumptions?
  • Every time you read/hear an argument, do this