In this video, Professor Thorsby discusses offers an overview of the first few sections of the Philosophical Investigations by Ludwig Wittgenstein. This represents Wittgenstein later work in which he adopts a very different view regarding the meaningfulness of propositions. Rather tRoughly speaking, this video introduces §1-75 of the first part of the text. Not all arguments are covered, but the major concepts are noted, including:
Language-games
Family Resemblances
Ostensive Definitions
Naming
The "Tractatus Logico-Philosophicus" is not covered. For a much greater review of his work see
https://books.google.com/books?id=bisiGaxtIlcC&lpg=PP1&dq=wittgenstein&pg=PP1#v=onepage&q=wittgenstein&f=false