After analyzing the elements of blood, he came to the conclusion that the red portion of fresh blood is the blood, the white material mixed with blood is the phlegm, the yellow-colored froth on top is the yellow bile, and the heavy part that settles down is the black bile. Essentially, according to this theory, human body is filled with these four humors, which are in equilibrium in the healthy state of the body. Any intermittent distribution of these humors will lead to diseases or disabilities. This theory was adapted by Greek, Roman, and Persian physicians and became widely accepted, dominating Western medical philosophy for over two centuries. However, this theory was continuously challenged when many medical researches were performed in the 16th and 17th century. Having the advantage of new technology, scientists used scientific methods to get a deeper understanding of human bodies. From the results collected, they could develop logic to arrive at an answer for the accuracy of this theory. It was officially falsified and discarded by the establishment of modern Western medicine in the 17th century, mainly due to William Harvey's discovery of the circulation of blood and the innovation of microscope. The elimination here is indispensable as the four humor theory was shown to be wrong and no longer useful to aid the pursuit of medical knowledge. .
I found a similar circumstance in human science while going through the timeline of macroeconomics in my textbook. Keynesian economics is an economic theory named after John Maynard Keynes, a British economist in the 19th century. This model supports the idea that the economy can be recovered and stimulated when the government assists it by increasing spending, deficit and debts. Using reasons as the main way to understand the situation of recession, Keynes concluded that more government spending and deficits could lead to a rise in aggregate demand in the economy.
