Porter vs Stout: What’s the Difference?

stout

I know I have asked myself this question many a time while sipping on one or the other.

The label says Porter, but why isn’t it a stout?  Is there a difference?  Does anyone really know?

I have curated several articles on the subject for your perusal.  As you will see, some claim there isn’t a clear, definitive answer, but others say there is a distinct difference, such as a strong roasted barley presence in a stout.  You decide!

And here are the official style guides from BJCP: