SCIENCE AND PSEUDOSCIENCE
Science is the study of all natural objects, processes, and phenomena of the Universe. It is the # 1 best approach and method for learning about the nature of reality. Science is based on making objective interpretations of all available facts and observations from nature. It is NOT based on beliefs - never has been, never will be, whether you like it or not. Scientific ideas have to be falsifiable, or testable. Any concept or idea that cannot be potentially tested to verify whether it's right or wrong or partially right or partially wrong is NOT part of science. One of the goals of science is to understand processes or phenomena so well that one can make successful predictions (in experimental science) or postdictions (in historical science).
In doing science, many often speak of "The" Scientific Method. This term implies that there is only one approach to doing science, as if scientists are following a recipe in a cookbook. This is far from the reality of the situation. There are many specific ways of doing science. How a particle physicist does science is different from how an archaeologist does science, which is different from how a chemist or a planetary geologist or a genetic engineer does science. However, all sciences attempt to objectively explain various natural objects, processes, and phenomena by gathering information, making observations, formulating hypotheses, testing those hypotheses, making objective interpretations, and formulating theories.
Two key terms in science are "hypothesis" and "theory". Misunderstanding and misuse of these two terms is widespread in the general public and, sadly, moderately widespread among scientists. For example, I often hear or read the phrase "competing theories" or "several theories" in reference to one set of concepts. There's NO SUCH THING AS COMPETING THEORIES.
Hypothesis - a rough idea or educated guess that explains how or why something works the way it does.
Theory - a rigorously tested hypothesis, or set of hypotheses, that successfully and consistently explains how or why something works the way it does.
There can be competing hypotheses. There is no such thing as competing theories, by definition. Scientists and nonscientists need to use these terms with care.
Sadly, considerable ignorance about science exists in modern society. This has resulted in many claims about the nature of science that range from slightly wrong to ridiculously wrong to enragingly-offensively wrong (Example: In 2008, Ben Stein said during a televised interview "Science leads to killing people.").
My favorite quotes about science:
1) "It's a very, very sad commentary on the values in our culture when shooting a ball into a basket is more laudable, more praiseworthy, more admirable, and more rewarded than teasing out some fundamental truth about the natural world or finding a cure for AIDS or cancer." (2009, Carolyn Porco - the real-life scientist behind the heroine of the movie Contact)
2) "Science is interesting, and if you don't agree, you can f*ck off." (Alun Anderson, editor of New Scientist magazine)
3) “Science will win because it works.” (2010, Stephen Hawking)
4) “All our science, measured against reality, is primitive and childlike and yet it is the most precious thing we have.” (1951, Albert Einstein)
5) “Science is the poetry of reality.” (2007, Richard Dawkins)
6) “The good thing about science is that it’s true whether or not you believe in it.” (2011, Neil DeGrasse Tyson)
7) "Our poets do not write about it; our artists do not try to portray this remarkable thing. I don't know why. Is nobody inspired by our present picture of the Universe? The value of science remains unsung by singers: you are reduced to hearing not a song or poem, but an evening lecture about it. This is not yet a scientific age." (1955, Richard Feynman)
SCIENCE AND PSEUDOSCIENCE
Because of society's widespread misunderstanding of science (mostly the result of intellectual apathy, educational laziness, the frequently-negative Hollywood depictions of science & scientists, and the bigoted anti-science agenda of relativism), pseudoscience and pseudoscientific ideas and pseudoscientists are everywhere.
Pseudoscience includes ideas that are not testable or ideas that have been already tested and shown to be wrong - it's as simple as that. There are many synonyms and near-synonyms of the term "pseudoscience" that include: fringe science, junk science, trash science, voodoo science, bad science, pathological science, cargo cult science, fraudulent science, alternative science, weird science, crackpot science, quack science, parascience, bogus science, malignant science, anti-science, non-science, and nonsense.
So, let's be specific - what past and present ideas out there are pseudoscience & nonsense?
Much of UFOlogy
Much of Cryptozoology
Intelligent Design Creationism
Climate Change Denial
Astrology & Horoscopes
Moon Landing Denial
Noah's Flood Geology
Extrasensory Perception (ESP)
California Breaking Off Into the Ocean
Smoking Health Risks Denial
Abiogenic Origin of Petroleum
Perpetual Motion Machines
Year 2000 Bug ("Y2K")
Polygraphs (Lie Detectors)
Large Particle Collider/Black Hole Catastrophe Predictions
Date-Specific End-of-the-World Predictions
Non-Human Origin of Crop Circles