In standard form every premise sits on its own line. But premises can work together in two different ways, and an argument map shows which.
Key idea
Linked premises support the conclusion only together: take one away and the other gives no support. Convergent premises are separate reasons: each supports the conclusion by itself.
Why it works
The difference matters when a premise turns out false. If premises are linked, one false premise breaks the whole support. If they are convergent, the other reasons still stand, and the case is only weaker.
Worked example: The cover test
"We should take the bus to the museum. The bus is cheaper than a taxi. The bus stops right at the door."
- Cover the first reason. Does "the bus stops at the door" still give a reason to take the bus? Yes.
- Cover the second. Does "the bus is cheaper" still give a reason? Yes.
- Each works alone, so the premises are convergent.
Answer: Convergent.
Worked example: Only together
"The hall holds 500 people. 500 tickets have been sold. So the concert is sold out."
- Cover the first premise: knowing 500 tickets were sold says nothing about sold out unless we know the size of the hall.
- Cover the second: knowing the hall size alone says nothing about sales.
- They support the conclusion only together.
Answer: Linked.
Common mistake
Treating every pair of premises as linked. Use the cover test: remove one premise and ask whether the other still gives some support by itself. If it does, they are convergent.