At some point, I gained the notion that inflections of a word didn't constitute different words, but rather different forms of the same word. This Wikipedia article however, says the process of inflection is a part of word formation, which is the creation of new words. The linked-to Wikipedia article on word formation however, doesn't list inflection as a type.
So, are different inflections of a word different words, or different forms of the same word? Or are there different opinions here?