The Human Truth Foundation

Scientific Theories Must Make Way for New Evidence

By Vexen Crabtree 2017

#knowledge #science #scientific_method

The nature of the scientific method lends itself to continual improvement in knowledge1, based on a continual stream of new data. Scientists spend "a great deal of time questioning and challenging one another"2 and frequently admit when their theories have been superseded or corrected by their peers3,4. The procedures of peer review and independent verification both ensure that mistakes in theory, application or analysis of data are spotted when other scientists examine and repeat the experiment. "The essence of science is that it is self-correcting" says the eminent scientist Carl Sagan (1995)5. Yet it is still rare that new evidence completely destroys a theory. Philosopher Bertrand Russell states that "theories, if they are important, can generally be revived in a new form"6. Hence, theories undergo continual improvement.

Still perhaps it may appear better, nay to be our duty where the safety of the truth is concerned, to upset if need be even our own theories, specially as we are lovers of wisdom: for since both are dear to us, we are bound to prefer the truth.

"Ethics" by Aristotle (350BCE)7

Sometimes, individual theories do have to be abandoned. Rarely, entire scientific paradigms are questioned such as when Newtonian physics gave way to Einstein. New evidence can cause entire theoretical frameworks to be undermined, resulting in a scientific revolution. "Science involves an endless succession of long, peaceful periods [... and then periods of] scientific revolution" (Kuhn 1962). To overthrow a theory requires strong evidence and a full cycle of the scientific method. To overthrow an established theory, which is often supported by many other theories and mountains of testing and evidence, requires extraordinary evidence8.


1. Errors in Thinking: Cognitive Errors, Wishful Thinking and Sacred Truths

#beliefs #pseudoscience #psychology #thinking_errors

We human beings, even while forming theories and conducting experiments, only have a limited capacity to think clearly and accurately. Our neural brains have evolved many methods of discerning what is true that are like shortcuts rather than logical analysis. As such, sometimes even trains of thought that seem clear turn out to result from mild self-delusion. It is not just apophenia (recognizing patterns that aren't really there) that can lead theorists astray, but many traits of human nature can belie the search for truth. Apart from cognitive errors in general thought, all humans are also subject to subjective desires, such as the desire to find supporting evidence for ones' own ideas.

We all suffer from systematic thinking errors9,10 which fall into three main types: (1) internal cognitive errors; (2) errors of emotion11, perception and memory; and (3) social errors that result from the way we communicate ideas and the effects of traditions and dogmas. Some of the most common errors are the misperception of random events as evidence that backs up our beliefs, the habitual overlooking of contradictory data, our expectations and current beliefs actively changing our memories and our perceptions and using assumptions to fill-in unknown information. These occur naturally and subconsciously even when we are trying to be truthful and honest. Many of these errors arise because our brains are highly efficient (rather than accurate) and we are applying evolutionarily developed cognitive rules of thumb to the complexities of life12,13. We will fly into defensive and heated arguments at the mere suggestion that our memory is faulty, and yet memory is infamously unreliable and prone to subconscious inventions. They say "few things are more dangerous to critical thinking than to take perception and memory at face value"14.

We were never meant to be the cool, rational and logical computers that we pretend to be. Unfortunately, and we find it hard to admit this to ourselves, many of our beliefs are held because they're comforting or simple15. In an overwhelming world, simplicity lets us get a grip. Human thinking errors can lead individuals, or whole communities, to come to explain types of events and experiences in fantastical ways. Before we can guard comprehensively against such cumulative errors, we need to learn the ways in which our brains can misguide us - lack of knowledge of these sources of confusion lead many astray16.

Learning to think skeptically and carefully and to recognize that our very experiences and perceptions can be coloured by societal and subconscious factors should help us to maintain impartiality. Beliefs should not be taken lightly, and evidence should be cross-checked. This especially applies to "common-sense" facts that we learn from others by word of mouth and to traditional knowledge. Above all, however, our most important tool is knowing what types of cognitive errors we, as a species, are prone to making.

"Errors in Thinking: Cognitive Errors, Wishful Thinking and Sacred Truths" by Vexen Crabtree (2008)

2. What is Science and the Scientific Method?

#epistemology #knowledge #science #truth

To counteract human thinking errors, we developed methods of spotting and correcting mistakes. Over a few thousand years, Human cultures got better at managing how to approach truth sensibly. The result is what we call science, and the safeguards are called the scientific method.

The "Scientific Method" is a set of steps taken to ensure that conclusions are reached sensibly, experiments designed carefully, data is interpreted in accordance with the results of tests, and that procedures can be verified independently. The system is designed to reduce as much Human error and bias as possible17. Ideas and theories must be subject to criticism, and counter-evidence must be taken into account in order to produce new and more accurate theories18. Everything should be questioned. Most people cannot "do" science and do not have the skills to analyse data in an adequate manner19. The Scientific Method is hard and demanding, with high standards of ethical conduct expected - Daniel C. Dennett wrote that "good intentions and inspiration are simply not enough" (2007)20. The effects of science can impact on all human development, changing entire societies21. Science has been responsible for a staggering increase in human knowledge, human technology and human capabilities over the last few centuries.4

"What is Science and the Scientific Method?" by Vexen Crabtree (2014)

Science is a human endeavor and, as such, is prone to bias, error, emotion, greed, hubris, and manipulation. All of these are human traits, and thus each researcher may be guilty of any of these failings. To be sure, these failings are present in every human activity [...]. Because science is largely self-correcting, these failings are usually rectified [...], science weeds out human errors over time in a way that no other major self-regulating institution does.

David Koepsell (2006 Sep/Oct)22 in the Skeptical Inquirer

3. Gradual Improvements in Scientific Theories

#science #scientific_method #theories

The nature of the scientific method lends itself to an acceptance of a continual improvement in knowledge, based on a continual stream of new data. "Science is a perpetual process of debate, analysis and reconsideration"1. Biologist Richard Dawkins points out that scientists frequently admit when their theories have been superseded or corrected by their peers3. Yet it is still rare that new evidence completely destroys a theory. Philosopher Bertrand Russell states that "theories, if they are important, can generally be revived in a new form after being refuted as originally stated. Refutations [...] in most cases [are] only a prelude to further refinements"6. The academic Patricia Barnes-Svarney, author of New York Public Library Science Desk Reference23, enthusiastically agrees and states "as any lover of science will tell you, it's precisely this dynamism that keeps science exciting"24.

The procedures of peer review and independent verification both ensure that mistakes in theory, application or analysis of data are spotted when other scientists examine and repeat the experiment. Scientists spend "a great deal of time questioning and challenging one another"2. Competing theories will have proponents that actively do not want new information threatening their own theory, so they will actively seek out weakspots in new experiments and new theories.

New scientists know that one of the best ways to advance their careers is to find a weakness in our current understanding of something and to correct it with a new or modified hypothesis. This is one of the reasons science has made such dramatic progress.

"Astronomy" by Fraknoi, Morrison & Wolff (2017)2

Many scientific publications report on the failures of data and experiments, and in the face of this and the criticism from peers, science self-regulates in a very efficient and detailed manner. "The essence of science is that it is self-correcting" says the eminent scientist Carl Sagan, "new experimental results and novel ideas are continually resolving old mysteries" (1995)5.

Sometimes, then, individual experiments are found to be faulty. Sometimes, the conclusions of the scientist are questioned even if the data is good. And sometimes, rarest of all, entire scientific paradigms are questioned such as when Newtonian physics gave way to Einstein. New evidence can cause entire theoretical frameworks to be undermined, resulting in a scientific revolution in understanding.

4. Replacing Old Scientific Theories With New Ones

#science #scientific_method #theories

Some theories are unsalvageable and are completely abandoned. Dr Harriet Hall states that to be a good scientist you must "be willing to follow the evidence and admit you are wrong if that's what the evidence says"4. It is considered bad form to cling on to an old, disproven idea. Theories tend to emerge together and tie-in with each other; so that often after a certain amount of progression a suite of theories will become outdated and a new group will replace them. "Science involves an endless succession of long, peaceful periods [... and then periods of] scientific revolution" (Kuhn 1962).

Often in science, models that fail some empirical test are modified in ways that enable them to pass the test on a second or third try. While some philosophers claimed this shows that falsification does not happen in practice, the modified model can be regarded as a new model and the old version was still falsified. I saw many proposed models falsified during my forty-year research career in elementary particle physics and astrophysics; it does happen in practice.

"God, the Failed Hypothesis: How Science Shows That God Does Not Exist"
Prof. Victor J. Stenger (2007)25

The idea of scientific "revolutions" in which a community of scientists is converted to a new way of thinking by new evidence is credited to the American philosopher and scientist Thomas Kuhn, particularly to his 1962 book The Structure of Scientific Revolutions.

One must be prepared to overthrow an entire theoretical framework - and this has happened often in the history of science - but there has to be strong contravailing evidence that requires it. It is clear that skeptical doubt is an integral part of the method of science, and scientists should be prepared to question received scientific doctrines and reject them in the light of new evidence.

Paul Kurtz in Skeptical Inquirer (2006)

The pioneering quantum scientist Paul Dirac, caveats this in saying that these 'revolutions' only occur in uncommon circumstances:

These big jumps usually consist in overcoming prejudice... and then a physicist has to replace this prejudice by something more precise, and leading to some entirely new conception of nature

"Science: A History in 100 Experiments" by John and Mary Gribbin (2016)26

The great scientist Max Planck argues that an alternative route is more common: old theories continue to be accepted, and it is the next generation who select the more truthful theories, silently letting the old ones fade away:

An important scientific innovation rarely makes its way by gradually winning over and converting its opponents: it rarely happens that Saul becomes Paul. What does happen is that its opponents gradually die out, and that the growing generation is familiarised with the ideas from the beginning.

Max Planck
Quoted in "Science: A Four Thousand Year History" by Patricia Fara (2009)27

Contrary to what is sometimes taught, science does not proceed by revolutions, except on very rare occasions. It is incremental, building on what has gone before. [...Sometimes, ] adherents to [a] failed hypothesis may try desperately to find a way to shore it up and explain things without accepting the experimental evidence. But in the long run, the truth will out - if only because the die hard really do die.

"Science: A History in 100 Experiments" by John and Mary Gribbin (2016)28

Once old theories are revealed to be problematic, and the need for new theories arise to explain new information, the cycle of the scientific method begins anew. It is a continual search for truth, led strictly by the evidence. Non-scientific minds often expect science to offer definite answers and absolute truth. However whenever a truth is declared absolute and beyond question, the search for truth becomes stagnant and eventually ludicrous as new data continues to come to light and cannot be explained or understood.

5. The Elements of the Scientific Method

  1. To Turn a Hypothesis Into a Theory, It Must Be Tested
  2. Systematic Literature Review and Meta-Analysis - Overcoming Selection Bias
  3. Peer Review - Overcoming Poor Design and Poor Argumentation
  4. Reproducibility and Independent Verification of Results
  5. Occam's Razor: Simplicity & Fewer Assumptions are Better
  6. Randomized Double-Blind Trials
  7. Be Open to Criticism and Make Way for New Evidence