I recently answered a question on Quora, titled “What is something possible in duck type programming, which is not possible in Scala?”. (Note: The title was later edited by the OP.) I took time to provide what I think is a good response. I am embedding it here so that more people benefit from it.
By the way, if this topic interests you, then you might also want to read Chris Smith’s “What to know before debating type systems”. (If you haven’t already read it, that is.)
This blog post was originally posted at my Blogspot blog at this URL.