♪ [music] ♪ - [Don] In our last video, we covered how
specialization in our work allows us as an economy
to produce more, but each of us also specializes
in how we use our minds. There's much to know, and each of our brains
has a very limited capacity to store and process knowledge. So it makes sense to divide
the tasks of processing knowledge across many different brains. We then trade the products
of our knowledge. Take medicine as an example. Science-based medicine
took off in the 19th century, springing from advances in biology,
physics, chemistry, and math, as well as from Darwin's
theory of evolution. Early specialties
included dermatology, gynecology, and pediatrics. This branching continues with more recent specialties,
like pediatric hematology, and female pelvic
reconstructive surgery. In fact, this specialization
has played an important role in my own life. When my son Thomas
was two years old, he contracted
a very serious digestive ailment. We took him to his pediatrician. The pediatrician
couldn't diagnose it. He eventually wound up
losing 20% of his body weight. Poor kid was really skinny. He spent a month in the hospital. Eventually, it took a specialist -- a pediatric gastroenterologist. Doctor Howard Boswick is his name. He wasn't just a pediatrician,
he wasn't just a gastroenterologist, he was someone
who specialized in studying the digestive ailments
of young children, and he applied
that specialized knowledge to the task of saving my son's life. And it worked. So today my son Thomas
is 17, he's healthy, thriving, but he's alive
only because, I'm convinced, of this incredible
specialization of knowledge that we were able
to take advantage of. If you could choose
what illness to get, would you choose a rare disease
or a common one? Assuming the diseases
are of similar severity you surely want the common one. Having a common illness means that there is likely
enough demand for treatment that someone will specialize
in treating it. A similar principle
was at play with my son. Doctor Bostwick could specialize because of the huge number
of people who live in New York or who can travel there
for treatment. It's only because of trade
that this specialization occurs. The bigger the market, the more potential patients
there are for suppliers of highly specialized
medical services. If Doctor Bostwick
lived in a small town he wouldn't be able
to make a living as a pediatric gastroenterologist. He'd have to be
a general practitioner. In a world without
specialized doctors my son might not be alive today. As Adam Smith said,
the size of the market matters. The greater the number
of potential trading partners, the more each of us can specialize. In a vast market,
such as the United States, almost all our exchange
is done with highly skilled, highly specialized, and hence,
highly productive partners. Specialization exists
everywhere you look: organic chicken farmers,
Bikram yoga teachers, Android app developers,
political speechwriters, corporate speechwriters, Asian fusion chefs, ice sculptors, and modelers of recursive
dynamic linear economies. I could go on
practically without end, but you get the point. Every one of us reaps
great benefits from trading
with other specialized minds. This division of knowledge leads not only
to higher productivity at producing
existing goods and services, but it also spurs innovation. In our next video, we'll sum up
some of what we've learned and talk about
the beauty of cooperation and comparative advantage. Here's the current
leader board of questions submitted from our viewers. ♪ [music] ♪