WHAT IS THE NATURE OF SCIENCE? • Please read the complete article which is posted at my website for you. • There is also a PPT summary posted at my website for you. Please use it for your exam reviews.
THIS IS THESCIENTIFIC WORLD VIEW • The Universe Is Understandable. • The Universe Is a Vast Single System In Which the Basic Rules Are Everywhere the Same. • Scientific Ideas Are Subject To Change. • Scientific Knowledge Is Durable. • Science Cannot Provide Complete Answers to All Questions.
WHAT IS THE NATURE OFSCIENTIFIC INQUIRY? • Certain features of science make it distinctive as a means of understanding the world/universe • Those features are especially characteristic of the work of professional scientists, but anyone can use them to think scientifically about many aspects of everyday life
Science Demands Evidence • The validity of scientific claims is settled by referring to observations of phenomena • Therefore, scientists concentrate on getting accurate data
THE SCIENTIFIC METHOD • Observe and describe a phenomenon or group of phenomena. • Formulate hypotheses to explain the phenomena; hypotheses often take the form of a proposed causal mechanism or mathematical relationship. • Use the hypotheses to predict the existence or actions of other phenomena, or to predict quantitatively the results of new observations. • Perform additional data collection or repeat experimental tests of the predictions by several independent experimenters using properly performed techniques or experiments.
THE SCIENTIFIC METHOD • Observations/Data ➔ Hypotheses ➔ Hypothesis Testing ➔ Models ➔ Laws ➔ Theories • At some point in time, each stage must be reported to the larger scientific community by presentations or publications.
THE SCIENTIFIC METHOD • The scientific method does not allow any hypothesis to be proven true. • Hypotheses can be disproven, in which case that hypothesis is rejected as false. • A hypothesis which withstands a test designed to falsify it establishes a level of probability that the hypothesis accurately explains data and can be used for further predictions, subject to further tests.
SCIENTIFIC LAWS AND THEORIES • A Scientific Theory is an explanation of a set or system of related observations or events based upon proven hypotheses and verified multiple times by detached groups of unbiased researchers. • (One scientist cannot create a theory; s/he can only create hypotheses.)
SCIENTIFIC LAWS AND THEORIES • As a result of our confidence in the Scientific method, both scientific laws and scientific theories are accepted to be “true” (accurate) by the scientific community as a whole. • A scientific law or a scientific theory is used to make predictions of events or relationships among data sets.
SCIENTIFIC LAWS AND THEORIES • The biggest difference between a law and a theory is that a theory is much more complex and dynamic. • A law governs a single action or situation, whereas a theory explains an entire group of related phenomena. (Mendel’s Laws versus Darwin’s Theory of Evolution by Natural Selection) • [Note: Evolution is a Fact; Darwin’s Theory is the scientifically accepted explanation for the fact(s) of evolution.]
SCIENTIFIC LAWS AND THEORIES • Genuine scientific theories must be falsifiable by means of additional application of the scientific method (data collection and hypothesis testing). • If one cannot imagine a specific investigation or experiment, based on predictions from the theory, leading to results which can further verify or refute the predictions, then the theory, as an explanation, is not scientific.
SCIENTIFIC LAWS AND THEORIES • By the time the scientific community accepts a Law or Theory, it represents the best understanding of the explanations for the propertied of a given system at that point in time. • A Scientific Theory represents our best understanding of the “truth” about some aspect of the universe, even though it is not proven as absolute and is still understood to be subject to future revision, or even to rejection.
THE EXPERIMENTAL METHOD • The Experimental Method is usually considered the most scientific of all methods, the “method of choice.” • The main problem with all other non-experimental methods is less control over the situation and its components. • The Experimental Method is a means of trying to overcome this problem of control.
THE EXPERIMENTAL METHOD • An experiment is a study of cause and effect. • It differs from non-experimental methods in that it involves the deliberate manipulation of one variable, while trying to keep all other variables constant. • Experiments must be properly designed and include controls.
HYPOTHESIS GENERATION • The use of logic and the close examination of evidence are necessary but not usually sufficient for the advancement of science. • Scientific concepts do not emerge automatically from data or from any amount of analysis alone. • Inventing hypotheses or theories to imagine how the world works and then figuring out how they can be put to the test of reality is a creative thought process.
SCIENCE EXPLAINS AND PREDICTS • Scientists strive to make sense of observations of phenomena by constructing explanations for them that are consistent with currently accepted scientific principles. • Such explanations—theories—may be either sweeping or restricted, but they must be logically sound and incorporate a significant body of scientifically valid observations. • The credibility of scientific theories often comes from their ability to show relationships among phenomena that previously seemed unrelated.
SCIENCE EXPLAINS AND PREDICTS • It is not enough for scientific theories to fit the observations that are already known. • Theories should also fit additional observations that were not used in formulating the theories in the first place; that is, theories should have predictive power.
SCIENTISTS TRY TOIDENTIFY AND TO AVOID BIAS • When faced with a claim that something is true, scientists respond by asking what evidence supports it. • But scientific evidence can be biased in how the data are interpreted, in the recording or reporting of the data, or even in the choice of what data to consider in the first place. • A scientist’s nationality, culture, sex, ethnic origin, age, political convictions, etc., may incline him to look for or emphasize one or another kind of evidence or interpretation.
SCIENCE IS NOT AUTHORITARIAN • It is appropriate in science, as elsewhere, to turn to knowledgeable sources of information and opinion, usually people who specialize in relevant disciplines. • But respected authorities have been wrong many times in the history of science. Aristotle
SCIENCE IS SELF CORRECTING AND PROGRESSIVE • In the short run, new ideas that do not mesh well with mainstream ideas may encounter vigorous criticism, and scientists investigating such ideas may have difficulty obtaining support for their research. • Challenges to new ideas are the legitimate business of science in building valid knowledge.
SCIENCE IS SELF CORRECTING AND PROGRESSIVE • SF Author Sir Arthur C. Clarke’s First Law: “When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”
SCIENCE AS A WAY OF KNOWING • The Universe Is Understandable. • The Universe Is a Vast Single System In Which the Basic Rules Are Everywhere the Same. • Scientific Ideas Are Subject To Change. • Scientific Knowledge Is Durable. • Science Cannot Provide Complete Answers to All Questions. Scientific ideas are developed by particular ways of observing, thinking, experimenting, and validating. Observations/Data ➔ Hypotheses ➔ Hypothesis Testing ➔ Models ➔ Laws ➔ Theories
Principles and Processesof Evolution • For the rest of the semester, we will be looking at the fact of Evolution and the evidence that supports Darwin’s/Biology’s Theory of Evolution by Natural Selection.