The enlightenment is at its core embracing science and reason. It is the rejection of tradition. That includes many ideas held by faith based religions. The US revolution and constitution are heavily influenced by the enlightenment.
Pinker supports the idea that moving beyond faith and tradition to reason, science and humanism is driving progress.
Population growth, automation and sustainable energy are all addressed in detail.
He rejects the idea of going back to simpler times and points out that in our nostalgia, we forget about the horrible things we've overcome like polio, famine and even war (comparatively). The data is really indisputable here.
A couple of more great points I've learned so far:
Organic farming is unsustainable. That is counter intuitive but the book explains it quite well. Organic farming takes many more times the amount of land and natural resources compared to using technologies like fertilizer, engineered seeds, hydroponics, etc. The argument is that all agriculture is human engineered. All our crops have been selectively bred to increase yield, reduce water needs, pest resistance, etc. What makes anyone believe that the technology we had 30 or 50 years ago is the right level and we should stop there. Advances in agriculture is what is feeding the world right now. Data shows that technological advances have allowed us to reduce the amount of land dedicated to farms. This leads to forrests reclaiming farmland that's no longer needed.
Pinker states that what we know of 'environmentalism' is actually holding us back. Ecomodernism shows how advancing technology can be used to solve environmental issues. For example moving from burning wood to coal to oil to natural gas for energy is a huge factor in reducing pollution. Cities allow for high efficiency with dense populations, less energy used for heat and transportation. There is a pretty strong call for nuclear power to take over, with some optimism that fusion may actually be for real in the near future.
I'm sure my paraphrased arguments have holes, but Pinker doesn't leave many in his near 500 page manifesto. It can get wordy at times, but I'm digesting and learning a lot from it. The facts used to back up each concept are compelling.