[matham]

I think this is the difference between a valid argument and a sound argument. A valid argument means the conclusion follows from the premise, kinda like the quoted argument in the article which seems to be valid.

A sound argument is one whose premises are also true. This is where the quoted argument in the article fails. The premises either are false or don't apply to all startups. This is basically what the author means by a argument that is missing premises. It's not really that a premise is missing, but that without additional into it may seem like the argument is sound,but with additional into you realize it is not sound and therefore leads to a different conclusion instead.