Scientific Methods and Human Knowledge -- Eric R. Pianka

Scientific Methods and Human Knowledge

© Eric R. Pianka

At the end of the Pleistocene (10,000 years before now), only about 500 generations ago, humans were still hunter/gatherers, living off the land in small bands or tribes. Natural selection shaped these ancestral human populations, both physically and mentally, to cope with the natural world around them. Like all animals, humans dwell in a three-dimensional world that they perceive on a local spatial scale within a limited time horizon.

Because our ancestors possessed very limited knowledge about how the world worked, they benefited by actively seeking evidence of connections among apparently unconnected events. As a result, humans today seem to be predisposed to look for causal connections by linking events whether or not they appear to be connected. We desperately want to understand and 'know' things in order to exploit our environment for our own ends. Our brains, shaped by natural selection, allow us to do this fairly well for immediate events and simple local phenomena using our five senses and logic (Orenstein and Ehrlich 2000).

However, more complex, large scale, time delayed, and elusive things beyond the reach of manipulation, direct observation, or our senses, are another matter. If we don't simply ignore them, we tend to resort to 'super'natural 'explanations,' invoking phenomena beyond those our sensory systems can detect. Some have even suggested that our tendency to believe in such 'super'natural phenomena might have a genetic basis (Morrison 1999; download "Evolution's Problem Gamblers"). Our ability to believe and place faith in 'super'natural (a misnomer, it should be called 'sub'natural) phenomena has doubtless helped humans make apparent 'sense' of otherwise puzzling or inexplicable phenomena or events. A predisposition for unquestioning belief in authority could spare each generation from repeating mistakes or having to rediscover or verify things that have already been discovered. It might also help us reach consensus on 'explanations' that cannot be verified. For example, many must have died in the process of finding out which plants and fungi were edible on a trial and error basis. Our ancestors no doubt sat around campfires telling one another stories, passing on such vital information from one generation to the next -- this was the origin of human knowledge, culture, and the beginning of our domination of planet Earth.

Development of verbal language allowed us to exchange and expand ideas and concepts better, no doubt facilitating control of our environment, and thereby our survival and reproduction. However, language is a double-edged sword: words help us formulate concepts, but at the same time, they limit the directions our thought processes can take. The ways in which we can envision the natural world around us are constrained by the words we develop, especially by the different meanings, attitudes, and emotions they can convey. Words, nouns in particular, can have very different referents between humans.

For example, the word 'mountain' means something quite different to someone raised in Colorado versus someone raised in Georgia. Precise definitions or universal agreement are needed to insure accurate passage of understanding.

Frail and limited as we are, humans have struggled long and hard to comprehend the world around us. Bound by our limited senses and life spans, we have nevertheless managed to begin to understand a fair bit about matter and nature. While we have difficulty imagining worlds with more than three dimensions or things without limits, it is a tribute to our intellect that we have words for concepts as elusive as hypervolumes, eternity, and infinity. For us, all things exist in three dimensions and must have a beginning and an end.

Humans explain events and phenomena in two very different ways. One approach to knowing (sense 1, common sense) involves thinking and is objective, based on making repeatable observations that allow us to predict nature and future events -- this rational logical approach to knowing led to scientific methodology (Moore 1999). Another, very different, non-objective approach to 'knowing' (sense 2, faith-based) is based primarily upon the invocation of 'super'natural explanations, bolstered by authorities who claim to have special access to 'super'natural sources. This non-scientific approach, championed by religions of all kinds, has helped many humans accept and cope with things they have no power to change or difficulty understanding rationally, such as unexpected deaths, other misfortunes, or natural disasters. Unfortunately, the power conferred on religious leaders has often led to serious abuses and resistance to accepting the rational understanding of the functioning of nature as demonstrated by new scientific discoveries. These two diametrically opposed ways we interpret and 'know' (sense 1 versus sense 2) about our environments have contributed to the regrettable past and modern day conflicts between science and religion.

Human intelligence has also evolved so that we have remarkably good abilities to detect intentions of other humans in social interactions. We seem to have a propensity for mysticism and a tendency to emphasize explanations that invoke intent over those based on sheer mechanism, situation, or circumstances. Indeed, humans may be predisposed to see intentions in their friends and enemies. Similarly, they attribute conscious thought and intention to the actions of non-human animals (anthropomorphism). For example, predators 'want' to kill us and prey 'want' to escape from us. We even look for meaning and purpose in inanimate things such as the climate or the universe. Thus a destructive storm is interpreted as having occurred because people strayed from religious tradition or did something wrong and had to be 'punished.'

Everyone, religious or not, relies on objective rational thinking to handle problems encountered in everyday life. Thus, we all know we must eat to stay alive, things fall down not up or sideways, we seek to avoid collisions when driving, balance our budgets, etc. Remarkably, many people switch back and forth between rational knowing (sense 1) to faith-based 'knowing' (sense 2) with ease. Our brains may be organized in ways that promote such duality (download Morrison's "Evolution's Problem Gamblers").

Adamant insistence on faith-based 'knowing' coupled with careless use of words like 'believe' and 'truth' have provided numerous opportunities to foment confusion and have allowed science to be deliberately maligned and misrepresented by those who stand to lose from changing sensibilities. Thus, religious leaders have often rejected new scientific evidence because it reduced the domain of processes over which religion could claim authority. As a result, scientific investigators have sometimes been vilified as Galileo was during the Spanish Inquisition -- scientists have even been tortured and executed because their views conflicted with mystical belief systems.

For various reasons, even many educated people still entertain faith-based systems of belief. Download Reg Morrison's "The origin of faith." They are comfortable with 'proofs' based on ancient mythology as the unchangeable 'truth'. People who 'know' something or 'believe' in 'super'natural 'proof' are thus unable and/or unwilling to use logic and reason to comprehend reasoned alternatives-- they cannot improve their understanding without substantial changes in their world view (a paradigm shift) and thinking processes. Religious beliefs can only be changed when a believer or an authoritative leader has some new 'revelation' or changes or rejects their current faith-based belief system. Sometimes, politically-motivated charismatic leaders create their own new faiths.

In contrast, scientific methods unrelentingly demand that we keep an open mind, leading to a continually improved understanding of the natural world about us. Scientists should never claim to 'believe' or to have access to the 'truth' (one who does will surely be last to find it!).

Scientists do not concern themselves with anything 'super'natural (again, 'subnatural' might be more appropriate), but they are interested only in naturally occurring phenomena. Motivated by curiosity about their surroundings, they assume an organized reality exists in nature and that objective principles can be formulated, which will adequately reflect that natural order. This pivotal assumption that an external organized reality exists is NOT based on faith, but is verified every day by observing predictable repeatable events such as day is followed by night. A scientist 'believes' that an organized reality exists, but in a fundamentally different and much more rational way than a religious person 'believes' in 'super'natural influences. Scientists go to great lengths to satisfy their desire to understand natural events and phenomena. They continually cross check one another to verify currently accepted explanations. For a scientist, reason and logic always trump authority and faith as a way of knowing (Moore 1999, Pianka 2000).

Superficial commonsense perceptions led our ancestors to invoke the notion of a 'flat Earth and moving Sun.' According to this view of things, Earth did not move and was at the center of the universe, with the Sun moving across the sky. Early mariners were actually afraid of falling off the flat Earth (strangely, nobody seemed to be overly concerned about either what supported this flat Earth or about ocean waters spilling off and draining into some sort of bottomless abyss -- why didn't the oceans drain dry?).

Over time, our understanding of the world around us has improved steadily as human knowledge has expanded. Our quest for understanding has liberated and enlightened many of us. For example, in Europe, during the Middle Ages, the origins of disease and other undesirable phenomena were thought to be the actions of demons, unseen creatures from Hell, that wrought havoc on the populace (Sagan 1997). Similarly, primitive peoples such as Australian, New Guinean, and African tribesmen attributed sickness to the influence of witches and spirits. We know now that illnesses are frequently caused by microscopic bacteria and viruses, and at least this can give us some level of comfort that our lives are not controlled by unknown malevolent forces wishing to do us harm. The ultimate result is that instead of continuing to burn witches at the stake, we have sought to create a medical profession.

However, the capacity for ambiguity inherent in language has also provided a ready mechanism that has unfortunately permitted some to obfuscate, conflate, and misinterpret those same ideas and concepts. Communication is impaired when people use the same words in different ways, whether deliberately or not. Many commonly used words suffer because of just such a 'failure to communicate.' Problems arise especially when words convey divergent attitudes. In the context of scientific versus vernacular terminology, key words such as 'fact,' 'know,' 'truth,' 'proof,' 'faith,' 'belief,' 'design' and 'theory' are widely misconstrued because they convey different meanings to different audiences. Another term that is a source of considerable confusion is 'random.' Let us consider some of these.

Most people consider a 'fact' as 'what really happened.' However, many 'facts' are not so clean and simple -- most involve varying levels of interpretation. Consider, for example, the apparently simple fact that the Sun rises each morning. Daily we receive new evidence confirming this fact. We can be quite confident that the Sun will rise again tomorrow. References to sunrise and sunset are based on now defunct concept of a "flat Earth and moving Sun".

Indeed, references to sunrise and sunset are based on this interpretation, which is supported by our superficial commonsense perceptions. Understandably, we think of ourselves at the center of the universe and interpret other events and phenomena from such an anthropocentric and geocentric frame of reference. But our understanding of cosmic events was greatly enhanced when instead of thinking of the Sun as moving, it is viewed as the center of a solar system (a heliocentric perspective), and Earth is interpreted as a rotating globe orbiting around a small star. Our vocabulary hasn't caught up-- clearly, we should refer to 'sunrise' as 'spinup' and 'sunset' as 'spindown' (Pianka 2000). In contrast, since the moon does revolve around Earth, it is appropriate to call its movements 'moonrise' and 'moonset'.

Nietzsche once wrote "there are no facts, only interpretation." He somewhat overstated the case, since repeatable observable events certainly qualify as 'facts' even though they may often not be clean of interpretation. We view the Sun's position change relative to the horizon every day, even though 'sunrise' is a misinterpretation. Although it took a long while to become accepted, the heliocentric solar system perspective has now replaced the geocentric concept in the minds of most people. Hopefully, it will not take as long for people to begin to accept Darwin's logical argument of natural selection.

Some people seem to need to believe in a deity to make sense of their existence and the phenomena they perceive around them. Perhaps 'knowing' that an omnipotent caring entity looks over us helps in confronting and coping with our human weaknesses and limited life spans. People are expected to outgrow their belief in the Tooth Fairy, the Easter bunny, and Santa Claus, but not the cherished myth of one or more omnipotent deities. Everybody wants to believe in a caring god and an afterlife, as comforting and irrational as that may be (but see below).

Unfortunately, some people of faith still favor ancient creation myths over an evolutionary explanation for our own origin, and some religious moderates that reject ancient myths still believe that a god intervened to create humans and establish moral values. Darwin's ideas threatened to dethrone humans as such exalted creatures (Dennett 1995). Many people remain convinced that humans are fundamentally different from other life forms -- they find it odious even to contemplate that we might have descended from a common ancestor of the great apes -- despite the fact that the vast majority of our genes are shared with chimpanzees and gorillas.
Indeed, these apes have the same blood group types as humans. All vertebrates share the same basic body plan. They are bilaterally symmetric, with a head, brain, nose, two eyes, paired forelimbs and hindlimbs, stomach, intestine, heart, kidneys, liver, and assorted other internal organs. Even a tiny fish or lizard shares all these features with humans. How can we not be related by descent? [Creationists might argue that good design(s) are/were used repeatedly, but it is much easier to explain shared derived traits as evidence of descent from a common ancestor.] Scientific evidence is overwhelming that all life on Earth arose from a single common ancestor. Your blood plasma approximates the salt concentrations of the oceans because life arose there. The genetic code is universal for all life forms
on Earth. Right now, genes that
first evolved in bacteria
billions of years ago in
Earth's primeval seas
operate respiratory meta-
bolism in the mitochondria
within your body that keep
you alive from second to
second. Green plants capture
solar energy using genes per-
fected by ancient photosynthetic bacteria, providing the energetic foundation that supports virtually all life on Earth. (Such microbes generated most of the oxygen that makes up Earth's current atmosphere, without which you could not exist.) Such scientific evidence tells us that humans are simply one terminal branch of the vast tree of life. Microbes, fungi and plants are our distant cousins. Some eastern philosophies share the belief that we are one part of a huge river of life flowing through time. Hence we do have an afterlife, after all, in the form of the ongoing tree of life, especially our descendants, and those of our relatives.

People who abandon reason on a regular basis and entertain irrational faith-based systems of belief are comfortable with 'proofs' based on ancient mythology. Anyone who 'knows' something or 'believes' in 'proof' is dogmatic and closed minded, mired down intellectually, unable and/or unwilling to use logic to comprehend reasoned alternatives -- such people cannot improve their limited understanding without substantial changes in their world view and thinking processes. Such certainty is a dangerous illusion.

Another much abused term with varied meanings is 'random.' The dictionary definition is "without definite direction" or "lacking a definite plan, purpose, or pattern" or "equi-probable." Often the word is used to describe anything capricious or unpredictable, which usually means that something is simply so poorly understood that it appears indeterminate. Invoking 'randomness' may often merely be a cover up for our ignorance. Because the basic source of genetic change is 'random' mutations, proponents of so-called "intelligent design" (actually creation mythology) mistakenly argue that "evolution is random." In actuality, natural selection favors the development of highly non-random organisms whose adaptations to cope with their environments enhance their reproductive success.

No self-respecting scientist should ever claim to 'believe' or to have access to the 'truth' (anyone who does will surely be the last to find it!). Instead, scientists rely on reason and should try always to remain open minded, discarding poor hypotheses in favor of better ones. As a result, scientific knowledge steadily improves understanding over time.

Unfortunately, scientists are people and people are fallible and subject to becoming dogmatic -- not all scientists practice the methods of science correctly, nor honestly, nor use potentially confounding words properly. And, although plenty of zealots stand ready to pounce on any such mistake to discredit scientists, unlike religion, science has powerful built in self-correcting mechanisms. Hypotheses are tested and tests are replicated to double check on their accuracy. In addition, the scientific profession comes down hard on individuals that cheat the system by falsifying data or cooking up conclusions. Once detected, such indiscretions typically result in the loss of such individual's jobs and an end to their 'scientific' careers. As Darwin himself once said, "Great is the power of steady misrepresentation, but the history of science shows how, fortunately, this power does not long endure."

Science, especially at introductory levels, is too often taught as fact-based transmission of information, with inadequate attention paid to its process. People are taught that science is a body of answers, deliverable in absolutes ('learn this for your exam') when they should be taught to think of science as a way of asking questions about the natural order of things. As a result, most people, including many who have taken several science courses, simply do not appreciate the scientific process of logical inquiry, especially the tentative and probabilistic nature of many scientific conclusions.

A widespread misconception is that science can explain everything -- quite the contrary, science thrives on uncertainty because it always remains tentative (in science, nothing is ever known for certain). Scientists must always remain open minded, discarding weak explanations in favor of ones that better explain observed events. The strength of scientific methods is that, if these processes are adopted and followed rigorously, understanding and knowledge will improve steadily over time. Dogmatic faith-based belief systems impair such progress by vigorously defending and maintaining the status quo of archaic systems of 'belief', preventing us from reaching our full human potential. Despite such impediments, scientific methods have brought human understanding a long way.

Scientists begin an investigation by formulating hypothetical statements about how reality might work, called hypotheses (also known as models). All hypotheses make simplifying assumptions -- some sacrifice precision for generality, whereas others sacrifice generality for precision. Some hypotheses actually sacrifice certain aspects of realism itself!

Hypotheses are "mere caricatures of nature designed to convey the essence of nature with great economy of detail" (Horn 1979). No hypothesis is "correct" or "true" -- any given hypothesis merely represents one particular attempt to mimic reality. All hypotheses are to some extent incorrect -- they have been likened to imperfect mirrors like those in circuses. Hypotheses generate predictions that can be tested by confronting them with reality. When a hypothesis's predictive powers fail, it is either discarded or revised. Hypotheses that do not conform adequately to reality are gradually replaced by others that better reflect the real world. The scientific method is thus self-regulating; as time progresses, knowledge expands and is continually refined and improved to reflect external reality better and better.

Observation and experiment play a vital role in science. They are used to test models, to refute inadequate hypotheses, and thus they help us to formulate improved interpretations of natural phenomena. Some natural events cannot be manipulated. Thus, we cannot stop the Sun's fusion or Earth's rotation to test current ideas, but each daily observation of spinup ("sunrise") and spindown ("sunset ") nevertheless strengthens our confidence in the accepted interpretation of celestial events.

In time, a well-substantiated hypothesis is elevated to become a robust scientific 'theory' (non-scientists often comment "it's just a theory," invoking a much more speculative and demeaning attitude). Eventually, reliable scientific theories can even attain the status of 'law,' such as the laws of motion or the laws of thermodynamics. Darwin's mechanism of natural selection is truly a unifying theory of life, not even restricted to DNA-based life on Earth, but it presumably would apply to any self-replicating entity (any life form) anywhere in the entire megaverse (Cosmos). Natural selection is as close to a 'law' as we can get in biology. People's world views and personal philosophies would benefit greatly from embracing "Darwin's Dangerous Idea" (Dennett 1995), rather than naïvely rejecting it outright and refusing to examine the evidence for it. We are extremely fortunate to be able to learn from past genius and research effort. In a few hours of careful reading, you can now master material that required many lifetimes to acquire.

Darwin ended "The Origin of Species" with "It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being growth with reproduction; inheritance which is almost implied by reproduction; variability from the indirect and direct action of the conditions of life, and from use and disuse; a ratio of increase so high as to lead to a struggle for life, and as a consequence to natural selection, entailing divergence of character and the extinction of less improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life . . ."

While an evolutionary perspective may dethrone humans as divine or special creations, it greatly enriches our understanding of the real world, much more so than one that invokes mythical or 'super'natural explanations such as some hypothetical deity who intervenes in human affairs at his whim.

Just as our ancestors used to think that Earth was at the center of the universe and the Sun moved over it, each of us quite naturally perceives ourself to be at the center of things. However, no one would deny that other events ultimately have their influence, too. Likewise, many people unconsciously place humanity at the exact center of the universe. In this view, the utility of anything is measured by how it can be used by humans. For many, everything has its dollar value. Such anthropocentrism is understandable, but narrow and misguided. I have sometimes been accused of being a misanthrope, but I am not. I value anyone who thinks and tries to live up to his/her full human potential. Everyone needs to find some middle ground along the continuum from anthropocentrism to misanthropism.

It is a worthwhile exercise to imagine that something else, such as an ant, a lizard, a rattlesnake, an oak tree, or even an HIV virus, is actually the focus of the Cosmos. From such a perspective, the almighty dollar quickly loses its primacy. Survival and reproduction assume a lot more significance.


Dawkins, R. and L. Ward. 1996. River out of Eden. HarperCollins.

Dennet, DC (1995) Darwin's Dangerous Idea: Evolution and the meanings of life. Simon and Schuster.

Holtz, B. 2007. Human Knowledge: Foundations and Limits:

Horn, H. S. 1979. Adaptation from the perspective of optimality. Pp. 48-61 in O. T. Solbrig, S. Jain, G. B. Johnson, and P. H. Raven, eds. Topics in Plant Population Biology. Columbia Univ. Press.

Levins, R. 1966. The strategy of model building in population biology. American Scientist 54: 421-431.

Moore, J. A. 1999. Science as a way of knowing: The foundations of modern biology. Harvard Univ. Press.

Morrison, R. 1999. The Spirit in the Gene: Humanity's Proud Illusion and the Laws of Nature. Comstock. Link to Reg Morrison's Essays (see especially "Evolution's Problem Gamblers")

Orenstein, R, and Ehrlich, P. 2000. New World New mind: Moving Toward Conscious Evolution. Doubleday.

Pianka, E. R. 2000. Evolutionary Ecology. Sixth Edition. Benjamin-Cummings, Addison-Wesley-Longman.

Sagan, C. 1997. The demon-haunted world: science as a candle in the dark. Random House, N. Y.

Last updated 13 January 2009 by Eric R. Pianka