The Nature of Scientific Evidence

Activity Goals 1. recognize how scientific explanations differ from non-scientific explanations. 2. recognize that scientific explanations can change, and why this happens. 3. recognize that some explanations are better than others, and why.

Important Points Science is about evidence: facts, observations, data, etc. Science is not about personal accounts, popular stories, etc. Scientific explanations must be changed when data provides insurmountable difficulties for the existing knowledge. Not all explanations are equally valid; some are "better" than others, simply because they work better, explain more observations.

What evidence do you have that the earth is not flat?

Instructions read handout "The Flat-Earth Round-Earth Controversy" by Weinberg/Magrane. work in groups to determine problems in the evidence given for the flat earth.

What makes the flat earth defense not science (pseudoscience)?

List characteristics of science

Six Criteria of Science: C.O.N.P.T.T. Consistent Observable Natural Predictable Testable Tentative

Consistency The results of repeated observations and/or experiments concerning a naturally occurring event (phenomenon) are reasonably the same when performed and repeated by competent investigators. The weight of the evidence is also compatible with well established observations and limits. REALITY CHECK #1: which of the following is a scientific statement, and which one is not a scientific statement? 1. Green plants will grow towards a light source. 2. Walking under a ladder will cause bad luck.

Observability The event under study, or evidence of the occurrence of the event, can be observed and explained. The observations are limited to the basic human senses or to extensions of the senses by such things as electron microscopes, Geiger counters, etc. (it’s measurable) If the phenomenon cannot be reproduced through controlled conditions, natural evidence of the event's occurrence must be available for investigation. REALITY CHECK #2: which of the following is a scientific statement, and which one is not a scientific statement? 1. Some plants eat meat. 2. Extraterrestrial beings have visited Earth.

Natural A natural cause (mechanism) must be used to explain why or how the naturally occurring event happens. Scientists may not use supernatural explanations as to why or how naturally occurring events happen because reference to the supernatural is outside of the realm of science. Scientists cannot conduct controlled experiments in which they have designed the intervention of a supreme being into the test. REALITY CHECK #3: which of the following is a scientific statement, and which one is not a scientific statement? 1. Green plants convert sunlight into energy. 2. A man parted the sea so some people could cross to the other side.

Predictability The natural cause (mechanism) of the naturally occurring event can be used to make specific predictions. Each prediction can be tested to determine if the prediction is true or false. REALITY CHECK #4: which of the following is a scientific statement, and which one is not a scientific statement? 1. Without sunlight (or comparable artificial light), green plants will die. 2. If you are a "Scorpio", your horoscope for today is “The greatest day of your life is coming soon."

Testability The natural cause (mechanism) of the naturally occurring event must be testable through the processes of science, controlled experimentation being essential. Reference to supernatural events or causes are not relevant tests. REALITY CHECK #5: which of the following is a scientific statement, and which one is not a scientific statement? 1. The Bermuda Triangle is an area of sky and ocean that causes ships and planes to sink and disappear. 2. Stanley Miller showed that living things could be made from non-living things under the right conditions with an experiment.

Tentativeness Scientific theories are subject to revision and correction, even to the point of the theory being proven wrong. Scientific theories have been modified and will continue to be modified to consistently explain observations of naturally occurring events. REALITY CHECK #6: which of the following is a scientific statement, and which one is not a scientific statement? 1. The number of human chromosomes was once "known" to be 48, but is now considered to be 46. 2. We know that the world began about 6000 years ago, and nothing will change that.

SUMMARY Science is a limited discipline that studies only naturally occurring events, while offering natural explanations for the phenomenon under study. The data must be consistent, observable, predictable, and testable, while any conclusions or theories must be tentative.

Energy-Boosting Necklace Stand beside and at arm’s length to the unknown object in the bag on the table. Do not touch the bag or the object. On the signal, with your arm outstretched, lift the bag about 30 cm off the table. Lower the bag back to the table. Put on the necklace. Lift the bag again, in the same manner.

The Necklace: A Scientific Explanation Lifting may feel easier the second time. Why? When a person tries to first lift the object his or her brain makes a rough estimate as to how much strength will be required. With an unknown object, this estimate will be inaccurate and, since the brick is small but heavy, the estimate will likely be an underestimation. The necklace test is the second try, by which time the person’s brain knows how much strength is required. So the muscles are prepared and the brick now seems easier to lift.

Scientific Inquiry Model (The Scientific Method) Current SI Model: Evidence-explanation-current scientific knowledge (NSES) Engage with a scientific question. Gather and analyze relevant evidence. Formulate explanations from evidence. Evaluate explanations in light of evidence and current scientific knowledge. Communicate explanations.

What Science Is/ Nature of Science Goal is to develop theoretical explanations of the observed world. Explanations should be consistent with current scientific ideas, logical, “fit the facts”, and have predictive power. Hypotheses about the world must be tested against reality. Validity of a scientific claim is established through evidence and reasoning.

Nature of a Scientific Theory/Explanation Consistent with itself and with other accepted theories. Zero or few assumptions. Testable and falsifiable. Based on repeated, controlled experiments. Changed in accord with new discoveries. Admits possible error rather than certainty.

Evidential Style of Belief The belief is held along with the evidence relevant to its rational assessment. The believer is capable of critically inquiring into the worthiness of the belief. The belief can be reconsidered in the face of contradictory evidence. The belief can change, based on the evidence.

Constructivism: Finding Out Existing Ideas Constructivist learning theory Importance of learner’s existing ideas May not cohere with scientific ideas, make sense to holder, hard to change Multiple choice: Definitely true, probably true, probably not true, definitely not true Supply answers and then more questions: I believe the earth is round (spherical) and not flat because….. Jean Piaget (1896-1980)

What is Pseudoscience? “False” science. Claims to be scientific or at an even higher level than science. Fails to comply with the usual scientific tests. Inconsistent with existing, well-established scientific knowledge.

Why Investigate Pseudoscience? Teach relevant science concepts. Clarify what science is (and is not). Engage students in scientific inquiry. Engage students in scientific thinking. Improve creative and critical thinking. Help develop an evidential style of belief. Equip students to evaluate future pseudoscientific claims, e.g., media.

Examples of Pseudoscience Mental Powers: ESP, mind reading, precognition, psychic surgery, auras Spirit World: contacting the dead, ouija board, channeling, astral travel, astrology Natural Mysteries: Boogeyman, Atlantis, crop circles, Bigfoot, Loch Ness monster Aliens & UFOs: flying saucers, Roswell, alien abductions, Men in Black

Claims Require Independent Testing Pseudoscientific claims are based on a non-evidential style of belief. Many pseudoscientific claims are never tested scientifically. When pseudoscientific claims are tested, methods, conclusions are questionable. Others cannot replicate test “successes.” Excuse given of “fragility” of phenomena.

“I Saw Bigfoot” Many pseudoscientific claims are based on personal, anecdotal evidence. Are essentially second hand stories: “I saw Bigfoot.” “I was abducted by aliens.” Problems: Very hard to verify or test Essentially unfalsifiable Collected in a haphazard way/filtered Argument from authority

Alternative Explanations of the Evidence Non-occurrence of the event: It didn’t happen. Human error, e.g., mistaken observations and/or inferences. Fraud/trickery, e.g., fake Bigfoot photos, stage magic masquerading as ESP. Chance, e.g., coincidental events, a long run of heads in coin flipping. Science.

Kraken: Alternative Explanations Unknown monster Sea monsters sighted since ancient times Stories of monsters battling whales Huge creatures attacking ships Many witnesses silent Deep sea unexplored Giant sea squid Sea “monsters” now identified - oarfish Sea squids battle sperm whales Sea squids have attacked ships Many stories told Sonar, submersibles

Occam’s Razor When we are faced with more than one hypothesis that explains the data equally well, we choose the simpler explanation. A hairy creature in the woods is more likely a bear than Bigfoot. An unknown object in the sky is more likely a balloon than a flying saucer. “When you hear hoof beats, think of horses not zebras.”

Could This Be Pseudoscience? Claim is first publicized thru mass media. Claim is sensational and exaggerated. Evidence for the claim is anecdotal. Claim contradicts known scientific principles. Claim uses scientific-sounding terminology in non-scientific ways.

Is a Pseudoscientist Making This Claim? Claimant has worked alone. Claimant says methods of discovery and testing the claim are secret. Claimant says the ruling elite is trying to suppress the claim. Claimant appeals to false authority. Claimant says a belief is reliable because it is ancient. Claimant seeks publicity and profits.

What’s Your Sign? Review the handout that describes the personalities related to each of the (unknown) signs of the Zodiac. Choose the description that you believe is closest to your “sign”. Tally how many participants choose their own sign and how many do not. Consider if the findings are significant.

Criticisms of Astrology Constellation names & limits are arbitrary Ophiucus, Cetus omitted from Zodiac Original signs, constellations out of step Planets are not “in” constellations There is no single moment of birth Doctor exerts greater G force than planets If many vague predictions are made, it is impossible to always be wrong

Instructions Read the "Balanced Treatment" article Is giving alternative theories to the shape of Earth scientific or pseudoscience? What other factors may be at play with this bill? Who are the stakeholders and what are they trying to accomplish?