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Welcome back to another installment of Do You Know Dewey! This time, we’ll be looking at the 100s classification, otherwise known as Philosophy and Psychology. While I enjoyed Psychology, Philosophy was my worst subject in college, so perhaps this is an area of the library that I need to spend more time browsing? What do you think? And do you care to join me?

100 (Philosophy)

Classification 100 is all about philosophy! From introductions and theories to dictionaries, concordances, and serial publications of philosophy, you can find all your general Philosophy 101 and Intro to Philosophy titles here!

110 (Metaphysics)

The 110s cover metaphysics. Think of this section as ideas of philosophy which are beyond our human comprehension: being, knowing, time, space, cause, existence and nonexistence, good and evil, the origins of life, chaos, force, energy, beauty, and eternity. Wow! What a varied and exciting selection!

120 (Epistemology, Causation, and Humankind)

The 120s get into Epistemology, which is the theory of knowledge. Another way of describing it would be to ask “How do we know?”. Armchair philosophers who wander into this area of the collection will find a whole host of fascinating theories. This classification covers the limits of knowledge, chance, doubt and denial, the self, and free will. The later 120s bring us to concepts of humankind, including the soul, the mind, death, reincarnation, and immortality.

130 (Parapsychology and Occultism)

Turn on your flashlights and grab your crucifixes! We’re getting into some creepy territory here! The 130s are devoted to occult studies (or, the study of hidden knowledge). Here are books on ghosts, haunted places, demonology, apparitions, divination, witchcraft, astrology, and curses. But, it’s not all scary. This section also includes New Age practices such as astrology, dream interpretation; Feng Shui; and Kabbalah.

140 (Philosophical Systems)

While 100 could be looked at as Philosophy in general, 140 is where you’ll find the works of specific philosophical schools. No, you’re not going to find your specific philosophers yet (that’ll be 180-190), but you’ll find movements, such as Individualism, Romanticism, and Pragmatism. Also in this section is Pantheism, Optimism, and Nihilism.

150 (Psychology)

Time to learn about the brain! Whether you want to learn about memory, emotions, the subconscious, or applied psychology, you can find it here. Mental illness, however, won’t be shelved in the 150s. That will be in 616, with diseases of the nervous system (remember how I said that Dewey tends to spread topics out?)

160 (Philosophical Logic)

Compared to some of the previous classifications, 160 feels relatively small. But, here you’ll find books on logic, that is, the science of reasoning. Argument, persuasion, fallacy, and deduction are all covered here.

170 (Ethics)

To quote Shakespeare: “There is nothing either good or bad, but thinking makes it so”. Do you agree? Ethics addresses the concept of what is right and wrong, and how we come to these conclusions. In addition to ethical systems (perfectionism, hedonism, etc.), the 170s cover political ethics, the ethics of family and relationships, of various professions, and even of our social relationships, like our friendships. Ethics of Sex and Reproduction covers controversial topics such as abortion and prostitution, while Other Ethical Norms includes a respect for life and nature, the treatment of animals (including animal testing), and other tough topics like euthanasia, genocide, and capital punishment.

180 (Ancient, Medieval, and Eastern Philosophy)

Remember how a few times I referenced that your favorite philosophers would be found in 180 and 190? Well, we’re finally there! In 180, we look at Ancient, Medieval, and Eastern Philosophy. There are technically three distinct areas all grouped together here: Ancient philosophies, such as the teachers of Pythagoras, Socrates, Aristotle, and Plato; Medieval Philosophies, such as Aquinas, Ockham, and Bacon; and Eastern Philosophies, such as Taoism, Confucianism, and the ancient and modern philosophies of countries like China, Japan, Korea, Egypt, Syria, Pakistan, and the Philippines.

190 (Modern Western Philosophy)

While the 180s contain ancient philosophy and the philosophies of the East, The 190s include pretty much everything else (that is, non-ancient or medieval philosophies of the West). If the philosophy was NOT ancient, medieval, or Eastern, then it can be found here. And there is quite the wide array of authors here, from Satre to Oprah!


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