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? a necessary precondition for understanding the mind-body problem. Dennett denies Nagel's claim that the bat's consciousness is inaccessible, contending that any "interesting or theoretically important" features of a bat's consciousness would be amenable to third-person observation. For instance, it is clear that bats cannot detect objects more than a few meters away because echolocation has a limited range. He holds that any similar aspects of its experiences could be gleaned by further scientific experiments. 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