Perhaps the best way of understanding this is by looking at the difference between a greek tragedy and a western drama, focusing mainly on the character development and their unfolding destinies within the world of the play. Now, I must note it has been a long time since I read this, but it should not matter as I read it pretty thoroughly. I would also recommend that if you do read it, read it quickly. I had a friend who read it too slowly and missed some of the ideas in volume 2.

Spengler regarded attic culture as only concerned with the eternal present. They viewed the phyiscal body as supreme over the inner will. The highest actualisation of this was in greek sculpure, the purest manifestation of their own expression: the eternal present. But if we extend this idea to their dramas, 'where the polis is present and individual destinies are subject to capricious fate' (Ebert), where the powers of the individual are limited to their involvement in the external, we see a pattern, or more aptly a living world view. Ebert shows how Greek drama began essentially as a dialogue between two parties that investigates the relationship and tension between an individual and the collective will of society. We see an external tension between several forces that always lead to a dynamic yet tragic end, in 'the tragedy'. Now, what does Ebert mean by capricious and why is that important? He means unpredictable and not dependent on the internal will of the hypocrites (character in greek), as the internal will is actually secondary to the external. Early attic greek plays saw a battle between parties whose destinies were interdependent on the confrontation, like two planets colliding. There was less focus on the inner struggle of one will or as Ebert aptly puts it 'there was not an emphasis on ones personal relationship with God,' which you see in western plays. Characters in a greek play are then treated more like pawns in a game of chess. Their inner struggles were much less important. There was less room for the Western idea of personal destiny where the protangonists internal will could be fealt pulsing through the atmosphere like a thunderstorm (see Hamlet) No, the greeks focused on the clash of wills and the unpredicability of destiny. The fullness of this revelation being shown through the physical exaltation or destruction of ones person which only could be actualised in the present moment (the body). Compare that to Faust, where the entire play focuses on a personal development: 'the erudite Faust is highly successful yet dissatisfied with his life, which leads him to make a pact with the Devil at a crossroads, exchanging his soul for unlimited knowledge and worldly pleasures' (Wikipedia, Faust, first sentence). The mark of a western play is a personal inner dialogue which holds everything together. The plot only develops if the internal character develops, and most importantly, every other character is dependent on the personality and inner will of the main character. The western protagonist's internal struggle determines the destinies of his close peers, his town or even the entire world (see Maestersinger by Wagner). In western play, the audience is supposed to relate to the internal world of the main character where as in greek plays the audience need not: they need only relate to the greater story and the sum of all its components, the entire game of chess.

The greek play is the opposite: the destiny of the individual is completely determined on the outer world as the outerworld shares a more intimate, connected relationship to the Body (the supreme part of the ego of the individual) than the inner world.

But in order to understand why they viewed the world in this way you must read the first volume. It helps if you are good at mathematics but not required.

(John David Ebert, “Mythologies of the Evolution of Consciousness: Oswald Spengler).