What is and is not

Let’s talk of what is and is not
If I say day, you say night
If I say friend, you say no friend
If I say here, you say gone
Me: eternal, you: ephemeral
Swim, drown
Walk, stumble
Smooth, abrasive
Sunny, buckets of rain
All the live long day, oh de do dah day
Let’s talk, let’s stop talking
Hello, Goodbye
Whose idea was it to talk in the first place?