Veterinary Medicine and the Philosophy of Science

Version 1.2 modified December 17, 2013   initial draft July 25, 1998


    The veterinary profession continues to experience controversies about which are valid modalities of practice versus which are not and what is science-based versus what is pseudo-science based or quackery. By oath, practitioners are bound to use the most efficacious modalities on their patients but what are these? Do components of acupuncture, homeopathy, aromatherapy or chiropractory offer more or less efficacious procedures than do similar procedures of more conventional medicine? With increasing basic knowledge from science, new methods emerge and old trusted ones are found lacking. At the clinical level, the principles from the discipline of clinical epidemiology and evidence-based medicine are the tools for empirically evaluating methods and for answering these questions in the clinical environment. But what is the philosophy underlying basic science and ultimately the progress of veterinary medicine? What is science? What is the process of science? What does the scientific process produce? How does the community of science function? What are scientific laws, theories and hypotheses? How do these relate to veterinary practice? How are scientific theories developed and discarded? What does it mean when theories proposed to explain a particular treatment modality are in conflict with more fundamental scientific theories? What portion of veterinary medicine is science-based? Clinicians with a clearer understanding of the history and philosophy of science will be better judges of claims about treatment modalities and the evidence supporting them when deciding whether or not they should become part of the clinician's armamentarium.

For definitions of general science terminology, see:

Science Terminology

Why the concern about understanding what is science, what is not and distinguishing between the two? Some quotes from over the years that convey the reason:

One accurate measurement is worth a thousand expert opinions - Grace Hopper (1906-1992)

Be very careful what you put in that head, because you will never, ever get it out.    Cardinal Wolsey (1475-1530)

It ain't so much the things we don't know that get us into trouble. It's the things we know that just ain't so. "Artemus Ward" (Charles Farrar Browne, 1834-1867

Man seeks to form for himself, in whatever manner is suitable for him, a simplified and lucid image of the world, and so to overcome the world of experience. . .   Albert Einstein (1937)

You cannot reason a person out of a position he did not reason himself into in the first place.   Johnathan Swift

For what a man more likes to be true, he more readily believes. Man prefers to believe what he prefers to be true. Francis Bacon (1561-1626)

The human understanding supposes a greater degree of order and equality in things than it really finds; and although many things in nature be sui generis and most irregular, will yet invest parallels and conjugates and relatives where no such thing is. Francis Bacon

For the mind of man is far from the nature of a clear and equal glass, wherein the beams of things should reflect according to their true incidence; nay, it is rather like an enchanted glass, full of superstition and imposture, if it be not delivered and reduced. Francis Bacon (Scientific American 5/04)

It is impossible for anyone to learn that which he thinks he already knows. Plutarch

My opinion, my conviction, gains infinitely in strength and success, the moment a second mind has adopted it. "Novalis" Friedrich von Hardenburg (1882-1801)

Ultimately, our troubles are due to dogma and deduction; we find no new truth because we take some venerable but questionable proposition as the indubitable starting point, and never think of putting this assumption itself to a test of observation or experiment. Will Durant

When you can measure what you are speaking about, and express it in numbers, you know something about it, but when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter be. (Lord Kelvin, 1858)

Certitude is not the test of certainty. Oliver Wendell Holmes, Jr. (1841 - 1935)

As usual the greatest assurance goes hand in hand with the greatest ignorance. (Feyerabend, 1978)

Nothing is worse than active ignorance... Nothing hurts a new truth more than an old error... Everyone hears only what he understands... The phrases men are accustomed to repeat incessantly, end by becoming convictions and ossify the organs of intelligence... We know accurately only when we know little. With knowledge doubt increases    Johann Wolfgang von Goethe

The chief cause of povetry in science is imaginary wealth. The chief aim of science is not to open a door to infinite wisdome but to set a limit to infinite error. Bertolt Brecht,Galileo

I know that most men, including those at ease with problems of the greatest complexity, can seldom accept even the simplest and most obvious truth if it be such as would oblige them to admit the falsity of conclusions which they have delighted in explaining to colleagues, which they have proudly taught to others, and which they have woven, thread by thread, into the fabric of their lives. -Tolstoy

The real purpose of the scientific method is to make sure Nature hasn't misled you into thinking you know something you actually don't know. Robert Pirsig, Zen and the Art of Motorcycle Maintenance

The discovery of truth is prevented more effectively not by the false appearance of things present and which mislead into error, not directly by weakness of the reasoning powers, but by preconceived opinion, by prejudice. - Schopenhauer

A absolutely clear and exhaustive understanding of any single thing in the world would imply a perfect comprehension of everything else.- Schopenhauer

Science . . . warns me to be careful how I adopt a view which jumps with my preconceptions, and to require stronger evidence for such belief than for one to which I was previously hostile. My business is to teach my aspirations to conform themselves to fact, not to try and make facts harmonize with my aspirations. Thomas Huxley, 1860 (Science 281:898)

Another thing I must point out is that you cannot prove a vague theory wrong.   . . . Also, if the process of computing the consequences is indefinite, then with a little skill any experimental results can be made to look like the expected consequences. Richard Feynman, 1964 (Science 281:903).

Whilst part of what we perceive comes through our senses from the object before us, another part (and it may be the larger part) always comes out of our own mind.   William James.

Another source of fallacy is the vicious circle of illusions which consist on the one hand of believing what we see and on the other seeing what we believe. Sir Clifford Allbutt

Science is not a set of definitive results but a way of understanding the world around us. Science is the gradual process of understanding that is achieved through careful refining and sharing of information and results. DH Levy, 1998.

The purpose of science in medicine is to attempt to get at the truth. Why should falsehood and ignorance be warm, while truth and knowledge should be cold? Only more and better science will perform the humane function of eliminating the errors encouraged by warm emotion. D. F. Horrobin, 1977.

All scientific work is incomplete-whether it be observational or experimental. All scientific work is liable to be upset or modified by advancing knowledge. That does not confer upon us a freedom to ignore the knowledge we already have, or to postpone the action it appears to demand at a given time. (AB Hill, 1965)

Believe those who are seeking the truth; doubt those who find it. (Andre Gide, 1869-1951)

No testimony is sufficient to establish a miracle, unless the testimony be of such a kind that its falsehood would be more miraculous than the fact which it endeavours to establish. David Hume, Of Miracles, 1748.

The final, proper and only trustworthy arbiters of research results are time and replication. W.A. Brown, 2001 (The Scientist, 15:17, 39.).

We have to remember that what we observe (what we learn about) is not nature in itself, but nature exposed to our method of questioning. W Heisenberg

The facts of nature are what they are, but we can only view them through the spectacles of our mind. Our mind works largely by metaphor and comparison, not always (nor often) by relentless logic. Stephen Jay Gould

Belief means not wanting to know what is true.
Convictions are more dangerous enemies of truth than lies.
Deep is the well of truth and long does it take to know what has fallen into its depths.
One's belief in truth begins with doubt of all truths one has believed hitherto.
(Friedrich Wilhelm Nietzsche, German philosopher, 1844 - 1900)

We tend to mistake our beliefs, which are thoughts about reality, for reality. Unknown (to me).

 Good Quotations by Famous People - Gabriel Robins

What is Science? Cheap Thoughts on Science (KA Boudreaux, Angelo State U)

References related to the philosophy of science:

The basic set: The following five books comprise a basic introduction to science, its logic, practice, philosophy and history. Reading these gives a good understanding of this area.

Schick, T,  L Vaughn, M Gardner. How to Think About Weird Things: Critical Thinking for a New Age, 6th ed., 2010  (Amazon)

Chapters (third edition):

  1. Introduction: Close Encounters with the Strange.
  2. The Possibility of the Impossible
  3. Looking for Truth in Personal Experience
  4. Relativism, Truth, and Reality
  5. Knowledge, Belief, and Evidence
  6. Evidence and Inference
  7. Science and Its Pretenders
  8. How to Assess a "Miracle Cure"uot;
  9. Case Studies in the Extraordinary
  10. Appendix: Informal Fallacies
  11. Epilogue: Mysteries in Perspective

If I were to select only one book to read, I would read this one. It is short, easy to read and covers in a clear, straightforward fashion the range from the occult to pseudoscience to miracle cures to UFO phenomenon. It explains why our senses and memory fail us and the logic necessary to interpret the reality our own observations and those of others.

Hatton, J, PB Ploufee, eds. (1997). Science and Its Ways of Knowing. 150 pp. pprbk Prentice Hall; ISBN 0132055767. (Amazon)

21 essays by renown scientists and philosophers on the nature of science and scientific knowledge in general, the relationships in science between fact and theory, about the nature of scientific theory, and about the kinds of claims on truth that science makes.

Mason, S (1962). A History of the Sciences. 638 pages, pprbk. Macmillan General Reference; ISBN 0020934009. ()

A very readable book on the origins of scientific thinking, methods and knowledge across the scientific disciplines from the earliest recorded times around the world and the social factors that impacted these. Understanding the histories of scientific disciplines helps the reader understand the rise of currently dominant paradigms and the fall of alternate paradigms, such as alchemistry, and the vestiges of the battles for dominance that remain today in medicine, science and culture.

Shapin, S (1996). The Scientific Revolution. 218 pgs, ppbrk. Univ Chicago Press, ISBN 0226750213.

A book that focuses the critical period during which the model of science as it is currently practiced developed, the improvement of the optical performance of the telescope and microscope, the transition from geocentric to heliocentric paradigm for the universe occurred and the foundations of chemistry as opposed to alchemy were laid.

Fetzer, JH, RF Almeder (1993). Glossary of Epistemology/Philosophy of Science. 147 pgs, ppbrk. Paragon House; ISBN 1557785597.

The readers of the philosophy of science literature need to understand the terminology as used by the philosophers of science because the definitions are sometimes different from common usage outside of this context. Although limited to the philosophy of science rather than philosophy in general, the words and definitions in this book have a bent toward those used by the more recent philosophers of science than the more traditional. A easily obtainable dictionary with a more conventional approach but broader coverage is that of Angeles, PA (1992). The Harper Collins Dictionary of Philosophy, 2nd ed.

Other books:

Bauer, HH (1994). Scientific Literacy and the Myth of the Scientific Method. 173 pgs. pprbk. Univ of Illinois Pr (Trd); ISBN 0252064364.

Dunbar, RIM (1996). The Trouble With Science. 213 pgs. Pprbk Harvard Univ Pr; ISBN 0674910192.

Kuhn, TS (1996). The Structure of Scientific Revolutions. 3rd ed, 212 pgs. pprbk., Univ Chicago Pr, ISBN  0226458083.

Gilovich, T (1991). How We Know What Isn't So: The Fallibility of Human Reason in Everyday Life. 216 pgs. Macmillan Inc ISBN 0029117054, pprbk  ISBN: 0029117062. (Cornell Univ.)

Sagan, C (1997). The Demon-Haunted World: Science As a Candle in the Dark. 457 pgs, pprbk. Ballantine Books (Trd Pap); ISBN 0345409469.

A good but somewhat long book on science versus pseudoscience written in more of a story fashion. The Schick book "cuts to the chase" more quickly. "There are many hypotheses in science which are wrong. That's perfectly all right; they're the aperture to finding out what's right. Science is a self-correcting process. To be accepted, new ideas must survive the most rigorous standards of evidence and scrutiny."

Excerpts from "The Fine Art of Baloney Detection", pp. 210-216 in above ( html)  

Carl Sagan's Baloney Detection Kit ( site2) from The Demon Haunted World (Excerpted from the book by Michael Paine)

Shermer, M. (2002, revised). Why People Believe Weird Things: Pseudoscience, Superstition, and Other Confusions of Our Time. Google Books excerpts (Amazon)

"Science is not the affirmation of a set of beliefs but a process of inquiry aimed at building a testable body of knowledge constantly open to rejection or confirmation. In science, knowledge is fluid and certainty fleeting. That is at the heart of its limitations. It is also its greatest strength." (p. 124)

  • Smart People Believe Weird Things: Rarely does anyone weight facts before deciding what to believe. Scientific American, Sept. 2002
  • How to be a skeptic - principles governing the persistence of scientific claims by pseudoscientists - excerpts from above in Natural History, April 1997

Strahler, AN (1992). Understanding Science: An Introduction to Concepts and Issues. 409 pgs, Prometheus Books; ISBN 0879757248.


  • Sutherland, WJ, D Speigelhalter, M Burgman (2013). Policy: Twenty tips for interpreting scientific claims. Nature 503:335-337 - pdf
  • Platt, JR (1964). Strong inference. Science 146:347-353.
  • - pdf  pdf2

    Certain systematic methods of scientific thinking produce much more rapid progress than others.

34 Principles of Knowledge, Reasoning and Evidence:

(from Schick, T,  L Vaughn, M Gardner (1995). How to Think About Weird Things, page no's. in "()"):

  • Just because something is logically possible doesn't mean that it is real. (17)
  • Just because a claim hasn't been conclusively refuted doesn't mean that it's true. (18)
  • Just because a claim hasn't been conclusively proven doesn't mean that it's false. (19)
  • Just because something seems physically impossible doesn't mean that it is. (19)
  • Just because something is physically possible doesn't mean that it's real. (24)
  • Just because something seems (feels, appears) real doesn't mean that it is. (35)
  • It's reasonable to accept personal experience as reliable evidence only if there's no reason to doubt its reliability. (62)
  • Just because you believe that something is true doesn't mean that it is. (72, 143)
  • Just because a group of people believe that something is true doesn't mean that it is. (73, 139)
  • There is such a thing as objective truth. (80)
  • We are justified in believing a proposition when we have no good reason to doubt it. (101)
  • There is a good reason to doubt a proposition if it conflicts with other propositions we have good reason to believe. (102)
  • The more background information a proposition conflicts with, the more reason there is to doubt it. (103)
  • When there is good reason to doubt a proposition, we should proportion our belief to the evidence. (104)
  • There is good reason to doubt a proposition if it conflicts with expert opinion. (107)
  • Just because someone is an expert in one field doesn't mean that he or she is an expert in another. (108)
  • If we have no reason to doubt what's disclosed to us through perception, introspection, memory or reason, then we're justified in believing it. (113)
  • Personal experience alone generally cannot establish the effectiveness of a treatment beyond a reasonable doubt. (152)
  • Case studies alone generally cannot establish the effectiveness of a treatment beyond a reasonable doubt. (163)
  • When claims of a treatment's effectiveness are based solely on case studies or personal experience, you generally cannot know that the treatment is effective. (164)
  • Scientific evidence gained through controlled experiments - unlike personal experience and case studies - generally can establish the effectiveness of a treatment beyond a reasonable doubt. (169)
  • Single medical studies generally cannot establish the effectiveness of a treatment beyond a reasonable doubt. (171)
  • When the results of relevant studies conflict, you cannot know that the treatment in question is effective. (172)
  • New study results that conflict with well-established findings cannot establish the effectiveness of a treatment beyond a reasonable doubt. (173)
  • Test-tube studies alone generally cannot establish the effectiveness of a treatment beyond a reasonable doubt. (176)
  • Animal studies alone generally cannot establish the effectiveness of a  treatment (for a different species) beyond a reasonable doubt. (177)
  • Observational studies alone generally cannot establish the effectiveness of a treatment beyond a reasonable doubt. (179)
  • Clinical trials with any of these limitations (lack of a control group, faulty comparisons, small numbers) generally cannot establish the effectiveness of a treatment beyond a reasonable doubt. (184)
  • A hypothesis is scientific only if it is testable, that is, only if it predicts something other than what it was introduced to explain. (201)
  • Other things being equal, the best hypothesis is the one that is the most fruitful, that is, makes the most novel predictions. (204)
  • Other things being equal, the best hypothesis is the one that has the greatest scope, that is, that explains and predicts the most diverse phenomenon. (207)
  • Other things being equal, the best hypothesis is the simplest one, that is, the one that makes the fewest assumptions. (209)
  • Other things being equal, the best hypothesis is the one that is the most conservative, that is, the one that fits best with established beliefs. (210)
  • We should accept an extraordinary hypothesis only if no ordinary one will do. (225)

Notes from On Scientific Thinking

(Tweney, RD, ME Doherty, CR Mynatt, eds. Columbia University Press, 1981)


Newton, Isaac Mathematical Principles of Natural Philosophy

The Rules of Hypothesizing:

  1. We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances.
  2. Therefore to the same natural effects we must, as far as possible, assign the same causes.
  3. The qualities of bodies, which admit neither intensification nor remission of degrees, and which are found to belong to all bodies within the reach of our experiments, are to be esteemed the universal qualities of all bodies whatsoever.
  4. In experimental philosophy we are to look upon propositions inferred by general induction from phenomena as accurately or very nearly true, notwithstanding any contrary hypotheses that may be imagined, till such time as other phenomena occur, by which they may be either made more accurate, or liable to exceptions.

Popper, Karl Conjectures and Refutations (biography)

  1. It is east to obtain confirmations, or verifications, for nearly every theory - if we look for confirmations.
  2. Confirmations should count only if they are the result of risky predictions: that is to say, if, unenlightened by the theory in question, we should have expected an event which was incompatible with the theory - an event which would have refuted the theory.
  3. Every "good" scientific theory is a prohibition: it forbids certain things to happen. The more the theory forbids, the better it is.
  4. A theory which is not refutable by any conceivable event is non-scientific. Irrefutability is not a virtue of a theory (as people often think) but a vice.
  5. Every genuine test of a theory is an attempt to falsify it, or to refute it. Testability is falsifiability; but there are degrees of testability: some theories are more testable, more exposed to refutation, than others; they take, as it were, greater risks.
  6. Confirming evidence should not count except when it is the result of a genuine test of the theory; and this means that it can be presented as a serious but unsuccessful attempt to falsify the theory. (I now speak of such cases of "corroborating evidence".)
  7. Some genuinely testable theories, when found to be false, are still upheld by their admirers - for example by introducing ad hoc some auxiliary assumption, or by re-interpreting the theory ad hoc in such a way that it escapes refutation. Such a procedure is always possible, bit it rescues the theory from refutation only at the price of destroying, or at least lowering, it scientific status. (I later described such a rescuing operation as a "conventionalist twist" or a "conventionalist stratagem".)

Stephen J. Gould on Science Facts and Theories

From Evolution as Fact and Theory, Discover, May 1981) (edited):

"In the American vernacular, "theory" often means "imperfect fact" - part of a hierarchy of confidence running downhill from fact to theory to hypothesis to guess. . . . (F)acts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. . . . Moreover, 'fact' doesn't mean 'absolute certainty'; there ain't no such animal in an exciting and complex world. The final proofs of logic and mathematics flow deductively from stated premises and achieve certainty only because they are NOT about the empirical world. . . . In science 'fact' can only mean 'confirmed to such a degree that it would be perverse to withhold provisional assent. I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms."

"The firm requirement for all science - whether stereotypical or historical - lies in secure testability, not direct observation. We must be able to determine whether our hypotheses are definitely wrong or probably correct."

Michael Shermer on Science:

From: Shermer M (1992). The triumph of the scientific method: The most precious thing we have. Skeptic 1(1):34-49.

Science is a set of cognitive and behavioral methods designed to describe and interpret observed or inferred phenomenon, past or present, aimed at building a testable body of knowledge open to rejection or confirmation.

Scientific facts are data or conclusions confirmed to such an exent it would be reasonable to offer temporary agreement.

Scientific progress is the cumulative growth of a system of knowledge over time, in which useful features are retained and non-useful features are abandoned, based on the rejection or confirmation of testable knowledge.

A scientific paradigm is a particular cognitive framework shared by some but usually not all members of the scientific community, designed to describe and interpret observed or inferred phenomenon, past or present, and aimed at building a testable body of knowledge open to rejection or confirmation.

The shift from one scientific paradigm to another may be a mark of improvement in the understanding of causality, the prediction of future events, or the alteration of the environment. It is, in fact, the attempt to refine and improve the paradigm that can ultimately lead to its demise, as anomalous data unaccounted for by the old paradigm (as well as old data accounted for but capable of reinterpretation) fit into the new paradigm in a more complete way.

Science is the best tool we have for understanding causality in all realms.

Baloney Detection: How to draw boundaries between science and pseudoscience

From: Shermer M (2001), Scientific American, 285:5, November, 285:6, December.

10 questions to ask when encountering any claim:

  1. How reliable is the source of the claim?
  2. Does this source often make similar claims?
  3. Have the claims been verified by another source?
  4. How does the claim fit with what we know about how the world works?
  5. Has anyone gone out of the way to disprove the claim, or has only supportive evidence been sought?
  6. Does the preponderance of evidence point to the claimant's conclusion or to a different one?
  7. Is the claimant employing the accepted rules of reason and tools of research, or have these been abandoned in favor of others that lead to the desired conclusion?
  8. Is the claimant providing an explanation for the observed phenomena or merely denying the existing explanation?
  9. If the claimant proffers a new explanation, does it account for as many phenomena as the old explanation did?
  10. Do the claimant's personal beliefs and biases drive the conclusions, or vice versa?

Six Symptoms of Pathological Science and Self-Delusion

(Dr. Irving Langmuir, 1932 Nobel Laureate, as condensed by DL Rousseau in: "Case Studies in Pathological Science: How the Loss of Objectivity Led to False Conclusions in Studies of Polywater, Infinite Dilution and Cold Fusion," American Scientist 80:54-63 (1992))

See also: Ramey, DW (1998). Pathological Science. World Eq Vet Rev 3(2):25-27.

1) Claimed effect being studied is often at the limits of detectability

Subjective visual observations replace objective instrumental measurements
The maximum observed effect is produced by an agent of barely detectable intensity

2) Investigators readily discard prevailing ideas and theories and disregard criticism of their new ideas and theories

Investigators concoct new ad hoc thories to account for the phenomenon

3) Investigators do not attempt critical experiments that could refute their new theory by determining whether or not the effect is real

Experiments done by others that refute the new theory are disregarded.

For a fuller definition, see "pathological science" in The Skeptic's Dictionary

Definition of Science in 1986 Amicus Curiae Brief to the Supreme Court:

(edited and paraphrased)

Note: This document is uniquely significant in that a large group of Nobel Laureates and others joined to, in part, define science. This had not been done previously by such a large group of distinguished scientists. For further information on the circumstances surrounding its origin, see: Shermer, MB (1991). Science defended, science defined: The Louisiana creationism case. Science, Technology Human Values 16:517-539. The following is that in the document which pertains to this definition.

No. 85-1513 On Appeal From the United States Court of Appeals For The Fifth Circuit, Amicus Curiae Brief of 72 Nobel Laureates, 17 State Academies of Science, and 7 other scientific organizations. (source of text on the Internet)

Science is devoted to formulating and testing naturalistic explanations for natural phenomena. It is a process for systematically collecting and recording data about the physical world, then categorizing and studying the collected data in an effort to infer the principles of nature that best explain the observed phenomena. Science is not equipped to evaluate supernatural explanations for our observations; without passing judgment on the truth or falsity of supernatural explanations, science leaves their consideration to the domain of religious faith. Because the scope of scientific inquiry is consciously limited to the search for naturalistic principles, science remains free of religious dogma . . . .

The scientific community has developed a vocabulary to describe the various aspects of the scientist's work. Although individual scientists are not always careful in their use of that vocabulary, a rigorous set of definitions can help to prevent confusion about what a scientific theory is. It can also provide a firm base on which to discuss the legal issues presented in this case.

The grist for the mill of scientific inquiry is an ever increasing body of observations that give information about underlying "facts." Facts are the properties of natural phenomena. The scientific method involves the rigorous, methodical testing of principles that might present a naturalistic explanation for those facts. To be a legitimate scientific "hypothesis," an explanatory principle must be consistent with prior and present observations and must remain subject to continued testing against future observations. An explanatory principle that by its nature cannot be tested is outside the realm of science.

The process of testing leads scientists to accord a 'special dignity' to those hypotheses that accumulate substantial observational or experimental support. This 'special dignity' is denoted by granting the title 'theory', which, when it explains a large and diverse body of facts is considered 'robust' and if it consistently predicts new phenomena that are subsequently observed it is 'reliable'. Facts are the world's data. Theories are explanatory ideas about those facts. If a theory successfully explains a large and diverse body of facts, it is an especially "robust" theory. If it consistently predicts new phenomena that are subsequently observed, it is an especially "reliable" theory. Even the most robust and reliable theory, however, is tentative. It follows from the nature of the scientific method that no explanatory principles in science are final. Even the most robust and reliable theory is tentative. A scientific theory is forever subject to reexamination and -- as in the case of Ptolemaic astronomy -- may ultimately be rejected after centuries of viability.

Every scientific discipline embraces a body of facts and one or more theories to explain them. Significantly for this case, scientific facts and theories are not interchangeable: An explanatory principle is not to be confused with the data it seeks to explain. This relationship between scientific theory and fact permeates all scientific disciplines; it unifies the enterprise of all scientists, from astronomers to zoologists.

Any body of knowledge accumulated within these guidelines is considered 'scientific'.

In an ideal world, every science course would include repeated reminders that each theory presented to explain our observations of the universe carries this qualification: 'as far as we know now, from examining the evidence available to us today.'

From Federal Judge W. R. Overton's previous ruling (as cited by Shermer above):

The essential characteristics of science:

  1. It is guided by natural law.
  2. It has to be explanatory by reference to natural law.
  3. It is testable against the empirical world.
  4. Its conclusions are tentative.
  5. It is falsifiable.

Evolution and the Nature of Science 

(Excerpts from "Teaching About Evolution and the Nature of Science, National Academy Press)

"Science is a particular way of knowing about the world. In science, explanations are restricted to those that can be inferred from confirmable data—the results obtained through observations and experiments that can be substantiated by other scientists. Anything that can be observed or measured is amenable to scientific investigation. Explanations that cannot be based on empirical evidence are not a part of science.

On the nature of science:

  1. First, science is not the same as common sense. Common sense indicates that the sun does rise and set. Nevertheless, there can be other explanations of that phenomenon, and one of them, the rotation of the earth on its axis, is responsible for day and night. A concept based on observation proved to need extensive modification as new observations accumulated.
  2. Second, the statements of science should never be accepted as "final truth." Instead, over time they generally form a sequence of increasingly more accurate statements. Nevertheless, in the case of heliocentricism as in evolution, the data are so convincing that the accuracy of the theory is no longer questioned in science.
  3. Third, scientific progress depends on individuals, but the contributions of one individual could be made by others. If Copernicus had kept his ideas to himself, the discovery of heliocentricism would have been postponed, but it would not have been blocked, since other astronomers eventually would have come to the same conclusion. Similarly, had Darwin and Wallace not published their hypotheses, the concept of biological evolution would nevertheless have emerged as the accepted explanation for the history of life on earth. The same cannot be said in other areas of human endeavor; for example, had Shakespeare never published, we would most assuredly never have had his plays. The publications of scientists, unlike those of playwrights, are a means to an end—they are not the end itself.

It is part of scientific inquiry to evaluate the results of scientific investigations, experiments, observations, theoretical models, and the explanations proposed by other scientists. Evaluation includes reviewing the experimental procedures, examining the evidence, identifying faulty reasoning, pointing out statements that go beyond the evidence, and suggesting alternative explanations for the same observations. Although scientists may disagree about explanations of phenomena, about interpretations of data, or about the value of rival theories, they do agree that questioning, response to criticism, and open communication are integral to the process of science. As scientific knowledge evolves, major disagreements are eventually resolved through such interactions between scientists.

Science distinguishes itself from other ways of knowing and from other bodies of knowledge through the use of empirical standards, logical arguments, and skepticism, as scientists strive for the best possible explanations about the natural world.

Scientific explanations must meet certain criteria. First and foremost, they must be consistent with experimental and observational evidence about nature, and must make accurate predictions, when appropriate, about systems being studied. They should also be logical, respect the rules of evidence, be open to criticism, report methods and procedures, and make knowledge public. Explanations on how the natural world changes based on myths, personal beliefs, religious values, mystical inspiration, superstition, or authority may be personally useful and socially relevant, but they are not scientific.

Because all scientific ideas depend on experimental and observational confirmation, all scientific knowledge is, in principle, subject to change as new evidence becomes available. The core ideas of science such as the conservation of energy or the laws of motion have been subjected to a wide variety of confirmations and are therefore unlikely to change in the areas in which they have been tested. In areas where data or understanding are incomplete, such as the details of human evolution or questions surrounding global warming, new data may well lead to changes in current ideas or resolve current conflicts. In situations where information is still fragmentary, it is normal for scientific ideas to be incomplete, but this is also where the opportunity for making advances may be greatest.

An Excerpt from the Book "This Is Biology: The Science of the Living World" (1997) by Ernst Mayr

The axiomatic assumptions or first principles of scientists:

  1. That there is a real world independent of human perceptions. This might be called the principle of objectivity (as opposed to subjectivity) or common-sense realism. This principle does not mean that individual scientists are always "objective" or even that objectivity among human beings is possible in any absolute sense. What it does mean is that an objective world exists outside of the influence of subjective human perception.
  2. That this world is not chaotic but is structured in some way, and that most, if not all, aspects of this structure will yield to the tools of scientific investigation. A primary tool used in all scientific activity is testing. Every new fact and every new explanation must be tested again and again, preferably by different investigators using different methods. Every confirmation strengthens the probability of the "truth" of a fact or explanation, and every falsification or refutation strengthens the probability that an opposing theory is correct. One of the most characteristic features of science is this openness to challenge. Often, in science, the absolute truth of a fact can be established. The absolute truth of an explanation or theory is much harder, and usually takes much longer, to gain acceptance.
  3. That there is historical and causal continuity among all phenomena in the material universe, and they include within the domain of legitimate scientific study everything known to exist or to happen in this universe. But they do not go beyond the material world.

Why Bogus Therapies Seem to Work  

(BL Beyerstein, Simon Fraser Univ, Skeptical Inquirer, 21.5 Sept/Oct 1997)

"If an "alternative" or "complementary" therapy:

  1. is implausible on a priori grounds (because its implied mechanisms or putative effects contradict well-established laws, principles, or empirical findings in physics, chemistry, or biology),
  2. lacks a scientifically acceptable rationale of its own,
  3. has insufficient supporting evidence derived from adequately controlled outcome research (i.e., double-blind, randomized, placebo-controlled clinical trials),
  4. has failed in well-controlled clinical studies done by impartial evaluators and has been unable to rule out competing explanations for why it might seem to work in uncontrolled settings, and,
  5. should seem improbable, even to the lay person, on "commonsense" grounds,

Why would so many well-educated people continue to sell and purchase such a treatment?"

"Mistaking correlation for causation is the basis of most superstitious beliefs, including many in the area of alternative medicine. We have a tendency to assume that when things occur together, they must be causally connected, although obviously they need not be.  .. Without comparison to a similar group of sufferers, treated identically except that the allegedly curative element is withheld, individual recipients can never know whether they would have recovered just as well without it."

List of "Ten Errors and Biases":

  1. The disease may have run its natural course.
  2. Many diseases are cyclical. (Even we epidemiologists benefit from this phenomenon in epidemics)
  3. Spontaneous remission; these can occur even for cancers that are nearly always lethal.
  4. The placebo effect; the reason for blinding. (In veterinary medicine, the placebo effect operates on the observers)
  5. Some allegedly cured symptoms are psychosomatic to begin with.
  6. Symptomatic relief versus cure.
  7. Many consumers of alternative therapies hedge their bets.
  8. Misdiagnosis (by self or by a physician). (A surprisingly common occurrence.)
  9. Derivative benefits.
  10. Psychological distortion of reality.

See also: Stevens P (2001). Magical thinking in complementary and alternative medicine. Skeptical Inquirer 25.6 Nov/Dec 2001

Questions for discriminating between pseudoscience and protoscience

(emerging science establishing its legitimacy)

 (modified from the initial list of 16 by Lee Moller, BCS Debates a Qi Gong Master, Rational Enquirer 6(4), Apr94)

  1. Would accepting the tenets of a claim require abandoning any well established, fundamental physical law or theory?
  2. Do proponents claim that because conventional scientific theories cannot be proven, which is true, their theories are of equivalent merit?
  3. Do proponents claim that the lack of evidence for a component of a conventional theory itself constitutes support for their theory?
  4. Has the discipline shown progress in understanding mechanisms and causal relationships?
  5. Does the discipline use scientific or technical words such as "vibration" or "energy" without clearly defining what they mean?
  6. Are popular articles on the subject lacking in references to the scientific literature?
  7. Is the only evidence offered anecdotal (case studies or case series of miraculous results) in nature?
  8. Do proponents of the subject claim that "air-tight" experiments have been performed that prove the truth of the subject matter and that cheating would have been impossible?
  9. Have the results of the aforementioned experiments been successfully replicated by other independent, skeptical researchers?
  10. Do proponents of the subject claim to be overly or unfairly criticized or to be the targets of a conspiracy or cover-up?
  11. Do proponents allege that disinterest or dismissal by conventional scientists is evidence of this conspiracy or cover-up?
  12. Is the subject only taught in non-credit institutions and not in major public research institutions as part of their main curriculum?
  13. Do proponents use alleged expertise in other areas to lend weight to their claim?
  14. Do proponents cite research credentials (e.g., PhD) without stating in what area the credential was awarded and by what institution?
  15. Do proponents cite faculty status (e.g., professor) without stating the institution that granted this rank?
  16. Are the best texts on the subject decades old?
  17. Do proponents of the claim use what one writer has called "factuals" -- statements that are a largely or wholly true but unrelated to the claim?
  18. When criticized, do the defenders of the claim attack the critic rather than the criticism, often using terms such as demolished, double standards, vapid, dirty tricks, dishonest, gamesmanship?
  19. Do proponents make appeals to history (e.g., this has been around a long time so it has to be true because if it wasn't it wouldn't have been)?
  20. Do proponents make appeals to weight of usage (e.g., thousands of Chinese use this therapy with great results) as evidence of efficacy?
  21. Does the subject display the "shyness affect"?     (Shyness effect: Demonstrable claims that can only be demonstrated when skeptics are not present or only when demonstrated to a sympathetic audience - Lee Moller)
  22. Do proponents use the appeal to ignorance argument ("there are more things under heaven than are dreamt of in your philosophy...")?
  23. Can you find relevant papers authored by the proponents in the relevant refereed scientific literature (e.g., such as on Medline Pubmed for medical subjects)?
  24. Are other papers in the relevant refereed scientific literature (e.g., such as on Medline Pubmed for medical subjects) by other independent investigators also supportive of the proponent's claims?

Another list, pdf

On-Line Resources:

General Science Terminology Glossary

The History and Philosophy of Science and Medicine:

Creationism / Intelligent Design Controversy:

Intelligent Design Watch

Other On-Line Resources:

Note: I've provided some key quotes and points from some of the following resources. For explanation, please see the on-line full text.

A Field Guide to Critical Thinking (J Lett, Indian River Comm Coll, Skeptical Inquirer, 1990)

A Liberal Education and Where to Find It  (T.H. Huxley, 1868 - argument on the necessity for all to understand science and the consequence of not)

Alternative Medicine and the Laws of Physics (RL Park, Univ Maryland, Skeptical Inquirer, 1997)

Bad Science (AB Fraser, Prof emeritus, Penn State Univ)

Critical Thinking: What is it Good for? (In Fact, What Is It?) Skeptical Inquirer March 2006

Dan Berger, MadSci Admin - History of Science (Bluffton College)

The Pathology Guy E. R Friedlander (E Friedlander, Univ Missouri Health Sciences pathologist)

European Enlightenment (Richard Hooker, World Civilizations, Washington State)

Free Inquiry (SD Schafersman, Univ Texas) (dead 1/11?)

Goodstein, David (Caltech vice provost)

How Science Works - pdf

Healthcare Reality Check (anti-quackery information and links, Georgia Council Against Health Fraud) (down 9/04)

Homeopathy and Science: A Closer Look (DW Ramey, DVM, M Wagner, PhD, RH Imrie, DVM` V Stenger, PhD)

Hypothesis Testing: Statistics as Pseudoscience (DH Johnson, USGS)

326 Articles/Books Questioning the Indiscriminate Use of Statistical Hypothesis Tests in Observational Studies (WL Thompson)

Introduction to the Scientific Method (F Wolfs, U Rochester) (S Milloy)

Lipps, Jere H. (Evolutionary Paleobiology Group, UC Berkeley)

Myths of Skepticism (MD Sofka, Rensselaer Polytech I) (shorter version) (pdf)

"Science is that application of formal and informal reasoning methods to understand and predict the natural and artificial worlds in which humans live. Central to science is a belief that the natural world is ordered; that it can be understood; and that it can be explained via natural processes without resorting to special causes, or the interventions of the supernatural. Science also places a very high priority on what can be observed and measured. The theories of science should be fruitful, inclusive, simple, and, to the degree possible, independently tested. . . . Science is first and foremost, however, a human activity. As such, its methods and conclusions are subject to the psychological, sociological, historical, religious and political assumptions of the individual and collective scientists. This does not invalidate science or its conclusions, but it does mean that scientist must apply the same formal methods to their own reasoning that they apply to the object of study. It is incumbent upon ethical scientists to make their own biases known when requesting research support, and when announcing the conclusions of that research."

On Science, Scientific Method And Evolution Of Scientific Thought: A Philosophy Of Science Perspective Of Quasi-Experimentation (Y Malhotra)

Philosophy, Science and Skepticism (MI Vuletic, U of Ill Chicago)

Frequently Encountered Criticisms in Evolution vs. Creationism: 2002 Edition

Quackwatch: Your Guide to Health Fraud, Quackery, and Intelligent Decisions (Stephen Barrett, MD)

Russel Turpin's "Characterization of Quack Theories"

sci.skeptic FAQ

The Scientific Method

Science and Philosophy

Science and Pseudoscience - London School of Economics - Lakatos

Science Haven: Surfing the Gap Between Arrogance and Stupidity (T Halwes)

Sense About Science

  • Peer Review And the Acceptance of New Scientific Ideas, 2004 (pdf)

Skeptics Quotes (many later proven wrong, of course)

Speculations of the Future of Science (Kevin Kelly, Edge: The Third Culture)

Stephen's Guide to Logical Fallacies (S Downes, University of Alberta)

Task Force for Veterinary Science: Dedicated to Reliable Health Information

Ten Myths of Science: Reexamining What We Think We Know (W. McComas, USC: Vol. 96, School Science & Mathematics, 01-01-1996, pp 10)

  • Myth 1: Hypotheses Become Theories Which Become Laws
  • Myth 2: A Hypothesis is an Educated Guess
  • Myth 3: A General and Universal Scientific Method Exists
  • Myth 4: Evidence Accumulated Carefully Will Result in Sure Knowledge
  • Myth 5: Science and its Methods Provide Absolute Proof
  • Myth 6: Science Is Procedural More Than Creative
  • Myth 7: Science and its Methods Can Answer All Questions
  • Myth 8. Scientists are Particularly Objective
  • Myth 9: Experiments are the Principle Route to Scientific Knowledge
  • Myth 10: All Work in Science is Reviewed to Keep the Process Honest

The Critical Thinking Community

The End of Science? (T Schick, Muhlenberg College, Skeptical Inquirer, 1997)

"Can science be shown to be a superior means of acquiring knowledge? Yes it can, but only by showing that it is more likely to yield justified beliefs than any other methodology. Thus the real issue is not whether a belief is scientific or pseudoscientific but whether it is justified or unjustified. . . .We are justified in believing something to be true when it provides the best explanation of the evidence. Science is superior to other methods of inquiry because it usually provides better explanations than they do. The goodness of an explanation is determined by the amount of understanding it produces, and the amount of understanding an explanation produces is determined by how much it systematizes and unifies our knowledge. The extent to which an explanation does this can be determined by appealing to various criteria of adequacy such as simplicity, scope, conservatism, and fruitfulness. No one wants to hold unjustified beliefs. The problem is that most people never learn the difference between a good explanation and a bad one. Consequently they come to believe all sorts of weird things for no good reason."

The Heuristics of Intellectual Due Process: A Primer for the Triers of Science (PDF E Beecher-Monas, NY Univ Law Review 75:1563-1657)

The Philosophy of Science Association

The Scientist's World (Geology 109, College of Marin)

Twenty Science Attitudes (Rational Enquirer, 3(3))

The description of 20 important attitudes about science and knowledge that are generally held by scientists, such as empiricism (look and see), determinism (cause and effect), parsimony, skepticism, precision, open mindedness, intellectual drive, awareness of assumptions, and appreciation of chance.


Crooked Timber

Respectful Insolence (a.k.a. "Orac Knows")

Sciencegate (science-minded journalists)

Science and Politics

  • Publishing hypotheses and data on a blog - is it going to happen on science blogs? (4/17/06)