In the fourth part of the series, Diarmaid MacCulloch makes sense of the Reformation, and of how a faith based on obedience and authority gave birth to one based on individual conscience. He shows how Martin Luther wrote hymns to teach people the message of the Bible, and how a tasty sausage became the rallying cry for Swiss Reformer Ulrich Zwingli to tear down statues of saints, allow married clergy and deny that communion bread and wine were the body and blood of Christ.

Laurie Anderson embarks on a cinematic journey through love, death and language. Cantering on Anderson's beloved rat terrier Lolabelle, who died in 2011, the film is a personal essay that weaves together childhood memories, video diaries, philosophical musings on data collection, surveillance culture and the Buddhist conception of the afterlife, and heartfelt tributes to the artists, writers, musicians and thinkers who inspire her. Fusing her own witty, inquisitive narration with original violin compositions, hand-drawn animation, 8mm home movies and artwork culled from exhibitions past and present, Anderson creates a hypnotic, collage-like visual language out of the raw materials of her life and art, examining how stories are constructed and told - and how we use them to make sense of our lives.

Dawkins opines that the moral framework of religions is warped, and argues against the religious indoctrination of children. He discusses specifically the idea of religion seen as a virus in the sense of a meme. He begins by explaining how a child is genetically programmed to believe without questioning the word of authority figures, especially parents – the evolutionary imperative being that no child would survive by adopting a sceptical attitude towards everything their elders said. But this same imperative, he claims, leaves children open to infection by religion.

The Pythagorian philosopher Plato hinted enigmatically that there was a golden key that unified all of the mysteries of the universe. It is this golden key that we will return to time and again throughout our exploration. The golden key is the intelligence of the logos, the source of the primordial om. One could say that it is the mind of God. With our limited senses we are observing only the outer manifestation of the hidden mechanics of self similarity. The source of this divine symmetry is the greatest mystery of our existence.

Dan Cohen, founder of the nonprofit organization Music & Memory, fights against a broken healthcare system to demonstrate music's ability to combat memory loss and restore a deep sense of self to those suffering from it.

All cooking is transformation, and in that sense, it's miraculous, it's alchemy. But of all the different transformations we call cooking, fermentation is the most miraculous and the most mysterious. And that's because it doesn't involve any applied heat at all. Discover how microbes help turn raw ingredients into delicacies like chocolate and cheese as Pollan tackles the mysterious process of fermentation.