There is an interesting answer on the french wikipedia article for Reflection (here)
Reflection can be decomposed in two parts:
- introspection: a program can examine itself.
- intercession: a program can modify its state/meaning.
So reflection is a ‘stronger’ property than introspection. That’s why you say type introspection for the ability to know types at runtime (and changing them is another action: conversion/casting).
EDIT: actually I just realized the first answer was saying exactly that ^^. Time to unplug myself…