The applications of science have built man a well-supplied house, and are teaching him to live healthily therein.
I like this analogy because with science we can "refurnish" what is understood to be true, and can replace old ideas with new and improved ones.
They have improved his food, his clothing, his shelter; they have increased his security and released him partly from the bondage of bare existence.
There are also other very useful improvements to life besides just the things mentioned. Science has vastly improved medicine, allowing us to live longer and healthier lives. Furthermore, there has been advancements in how we communicate, which bring us closer together as a world.
suggesting that they are best understood as a replacement for traditional textbooks.
Saying MOOC's serve as a replacement for traditional textbooks is an important distinction. Reading a textbook will teach you a lot of information, but is not quite the same as taking the class, which is an important difference which should be recognized.