Currency relative values of the different currencies. Currencies in this sense are defined by governments, and each type has limited boundaries of acceptance. Other definitions of the term "currency" are discussed in their respective synonymous articles banknote, coin, and money. The latter definition, pertaining to the currency systems of nations, is the topic of this article. Currencies can be classified into two monetary systems: fiat money and commodity money, depending on what guarantees the value (the economy at large vs. the government's physical metal reserves). Some currencies are legal tender in certain political jurisdictions. Others are simply traded for their economic
What Is it Like to Be a Bat? What Is it Like to Be a Bat? "What is it like to be a bat?" is a paper by American philosopher Thomas Nagel, first published in "The Philosophical Review" in October 1974, and later in Nagel's "Mortal Questions" (1979). In it, Nagel argues that materialist theories of mind omit the essential component of consciousness, namely that there is something that it is (or feels) like to be a particular, conscious thing. He argues that an organism has conscious mental states, "if and only if there is something that it is like to be that organism—something it is like "for"