Making messages specific by sending additional information
Could write separate method for every possible combination of circumstances, but unwieldly and repetitive
- where, when, and with whom is a meeting?
- in which component should another appear?
Parameters allow us to generalize methods
what is all this jargon?
Formal parameters are "dummy" variables that represent instances sent when calling method, for internal use only
Actual parameters are "actual" instances sent when calling method
- placeholders, like x in 2x+5
- have no value of their own; take on value of actual parameters passed in when method is called