Why do some scholars propose that the book of Isaiah has multiple authors?
Doubts about the authorship began in the 12th century when Rabbi Ibn Ezra speculated it wasn't written by Isaiah. He famously quipped against the norm that claimed Isaiah wrote the book given that it's his namesake, that Samuel could have written the book of Samuel up until it says, "And then Samuel dies". The rational is that Isaiah chapter 1-39 fits the political context of the 8th Century B.C. Assyria was Israel's main threat at that time, and Assyria is mentioned 39 times. Between Isaiah chapters 40-55, Assyria is only mentioned once, in the past tense (Isaiah 52:4). In Isaiah 40-55 Babylon is the central threat, which makes the most sense if it is contextualized in the 6th century B.C. It would be akin to reading a document that claimed Germany is a threat to America, and another document that claimed ISIS is a threat to America, one might conclude that the first document was written in the early 20th century and the second document was written in the 21st century. Once the reader arrives to Chapter 40-55, they will notice that the writer has knowledge of Babylonian gods (Ch. 41:6-7, 21-24, Ch. 55:9-20, 25, Ch. 46:1-2), which doesn't make sense in the 8th century. There are also stylistic differences. Chapter 1-39 has short, striking, staccato poetry whereas chapter 40-55 has longer, ponderous, majestic poetry. Chapter 1-39 is preaching against a corrupt people, warning against God's judgment. Chapter 40-55 is offering a message of hope and return for a people in exile. A third distinction comes between chapter 55 and 56, from chapter 56-66 Jerusalem appears to have been restored (Ch. 62:6, 63:1, 66:10). There are references to the temple and sacrifice (60:6-7, 62:9). The concern for sin and judgment has returned (59:1-8, 18-19). None of these make sense during the Exile period is the 6th century B.C., but does make sense if this section of the book was written after the restoration of Jerusalem, when the Persians conquered the Babylonians. For these reasons many scholars reached the conclusion that Isaiah has at least three different authors, from three separate time periods.
How have Kant's categories impacted philosophy?
Prior to Kant there were rationalists like Descartes who believed that knowledge begins with logical or mathematical ideas (that if A = B, and B = C, therefore A = C, or that 2 + 2 = 4). We apply these concepts, that we are born knowing, to the world around us and construct our beliefs according that. Opposed to the rationalists were the empiricists, like John Locke or David Hume, who believed that knowledge begins with experience. We aren't born simply knowing the law of non-contradiction, we abstract it from the observations we've made. We abstract that 2 + 2 = 4, by counting two objects, and counting another two objects, then count that they've added up to four objects. Thus we have a debate between rationalists and empiricists. In steps Kant. He argues that all knowledge begins with experience, but that our experience of the world is guided by innate presuppositions - categories. These innate ideas are empty until we have an experience to add content to them. When I interact with a table, I'm interpreting the experiencing according to certain biases - innate ideas or presuppositions. I assume the table had a cause - a manufacturer - at some point in the past. I don't really know anything prior to my experience with the table, but my assumption is still there. What is the world like independent of our presuppositions? There's the world as we interpret it, and the world as it actually is. Philosophers and scientists began to speculate that concepts such as space and time don't operate the way we perceive that they do. The world might be quite different from the way in which we experience the world. Outside of philosophy, Einstein attributes Kant for prodding him to rethink Newton's physics and it's concepts of space and time. 20th century physics has operated on the assumption that space and time are very different from the way we perceive space and time, and in large part, this is because of Kant.
How do changes in national interest rates effect the economy?
Interest rates determine banking behavior. At low interest rates, more people qualify for loans to purchase things such as a house through a mortgage or a car through a car loan. If the interest rates are lower, then the cost of borrowing decreases - the mortgage has a lower price tag attached to it. The laws of supply and demand suggest that at lower prices, more people will be interested in purchasing these loans (if a mortgage payment is low, more people will wish to purchase a house, or if a car loan payment is low, more people will purchase a car). This means that at low interest rates, the economy will move faster because people are buying more products. With more house purchases, there will be a greater need for more construction workers, more real estate agents, and more mortgage brokers for example. The more people purchase cars, the greater the demand will be for sales people to sell the cars, for manufacturers to build them, and mechanics to repair them. However, because the economy is moving faster there is a risk that inflation could set in. As more people demand a product, the more sellers will charge a higher price for the product. As prices rise, inflation sets in. So to avoid major inflation, central banks will increase rates. In summary: to stimulate an economy, central banks will lower interest rates, and to combat inflation, central banks will raise interest rates.