This document discusses the importance of critical thinking in scientific understanding. It argues that our natural thought processes are biased and we must learn to think scientifically. Some key points made: - Our thoughts are often biased by preconceptions, so science aims to minimize bias through critical methods. - A critical approach to science focuses on understanding reasons and thinking through ideas, not just memorizing facts. - Students must confront and modify their own preconceptions to truly understand scientific concepts. - Scientific thinking involves continually questioning observations and testing hypotheses through experimentation, rather than following a set series of steps. Developing a scientific habit of mind is more important than finding the right answer. - To begin thinking

1. A Critical Thinking Framework for
Understanding Excellence in Biological Thinking
adaptedfrom Intellectual Standardsand Scientific Thinking by Dr. Linda Elder and Dr. Richard Paul
Humans live in a world of thoughts. We accept some thoughts as true. We reject others as false. The
thoughts we perceive as true are sometimes false, unsound, or misleading and the thoughts we perceive as
false and trivial are sometimes true and significant.
The mind doesn't naturally grasp the truth. We don't naturally see things as they are. We don't
automatically sense what is reasonable and what unreasonable. Our thought is often biased by our agendas,
interests, and values. We typically see things as we want to. We twist reality to fit our preconceived ideas.
Distorting reality is common in human life. It is a phenomenon to which we all unfortunately fall prey.
The practice of science, however, is a philosophy of determining truth through methods that minimize
our predispositions of thought. A critical approach to learning science is concerned with learning to think
scientifically (and less with accumulating undigested facts and scientific definitions and procedures). As we
learn to think scientifically, we inevitably organize and internalize facts, learn terminology, and use scientific
procedures. But we learn them deeply, because they are tied into ideas we have thought through, and hence
do not have to "re-learn"later.
The biggest obstacle to understanding science for most of us is our previous conceptions. Growing up we
develop our own ideas about the physical world - many of which are false. What school texts say usually does
not change our inner beliefs. Unscientific beliefs continue to exist in an unarticulated and therefore
unchallenged form in our minds. For example, in one study, few college physics students could correctly
answer the question, "What happens to a piece of paper thrown out of a moving car's window?" They
reverted to a naive version of physics inconsistent with what they learned in school; they used Aristotelian
rather than Newtonian physics. The Proceedings of the International Seminaron Misconceptions in Science
and Mathematics offers another example. A student was presented with evidence about current flow that
was incompatible with his articulated beliefs. In response to the instructor's demonstration, the student
replied, "Maybe that's the case here, but if you'll come home with me you'll see it's different there.” This
student's responsegraphically illustrates one way we retain our own beliefs: we simply juxtapose them with
anew belief. Unless we practice expressing and defending our scientific beliefs, and listeningto those of
others, we will not critique our own beliefs and modify them in accordance withwhat we learn while studying
science.
Typical science texts present the finished products of science. Students are oftenrequired to practice the
skills of measuring, combining liquids, graphing, and counting, butsee no reason behind it. The practice
becomes mindless drill.Texts also introduce scientific concepts. Yet few people can explain scientific concepts
inordinary language. For example, after a unit on photosynthesis, it would not be uncommonfor students
who were asked, "Where do plants get their food?" to reply, "From water, soil,and all over.” Students often
misunderstand what the concept 'food' means for plants(missing the crucial idea that plants make their own
food).
Students need to understand the reasons for doing experiments or for doing them ina particular way. Lab
texts often fail to make explicit the link between observation andconclusion. Rarely do students have
occasion to ask, "How did we get from that observationto that conclusion?" The result is that scientific
reasoning remains a mystery to most nonscientists.
A critical approach to learning science requires us to ponder questions, proposesolutions, and think
through possible experiments.
Many texts treat the concept of "the scientific method" in a misleading way. Not allscientists do the same
kinds of things-some experiment, others don't, some do fieldobservations, others develop theories. Compare
what chemists, theoretical physicists,zoologists, and paleontologists do. Furthermore, scientific thinking is
not a matterof running through a set of steps one time. Rather it is a kind of thinking in whichwe continually
move back and forth between questions we ask about the world andobservations we make, and experiments
we devise to test out various hypotheses, guesses,hunches, and models. We continually think in a

2. hypothetical fashion: "If this idea of mineis true, then what will happen under these or those conditions? Let
me see, suppose wetry this. What does this result tell me? Why did this happen? If this is why, then that
shouldhappen when I ... " It is more important for students to get into the habit of thinkingscientifically than
to get the correct answer through a rote process they do not understand.The essential point is this: we
should learn to do our own thinking about scientificquestions from the start. Once we give up on trying to do
our own scientific thinking andstart passively taking in what textbooks tell us, the spirit of science, the
scientific attitudeand frame of mind, is lost.
General Scientific Practices
If there is not “THE Scientific Method” and the products of science are mostly what will be presented in the text,
where can we begin? What is the “I think, therefore I am” in the discipline of science? Scientific thinkingis based
on a belief in the intelligibility of nature, that is, upon the belief that the same cause operating under the same
conditions, will result in the same effects at any time in the physical world.As a result of this belief, in their
discipline, scientists practice the following:
They Observe. (What conditions seem to affect the phenomena we are observing?) In order to determine the
causal relations of physical occurrences or phenomena, scientists seek to identify factors that affect what they are
studying.
They Design Experiments. (When we isolate potential causal factors, which seem to most directly cause the
phenomena, and which do not?) In scientific experiments, the experimenter sets up the experiment so as to
maintain control over all likely causal factors being examined. Experimenters then isolate each variable and
observe its effect on the phenomena being studied to determine which factors are essential to the causal effect.
They Strive for Exact Measurement. (What are the precise quantitative relationships between essential factors
and their effects?) Scientists seek to determine the exact quantitative relationships between essential factors and
resulting effects.
They Seek to Formulate Physical Laws. (Can we state the precise quantitative relationship in the form of a law?)
The quantitative cause-effect relationship, with its limitations clearly specified, is known as a physical law. For
example, it is found that for a constant mass of gas, at a constanttemperature, the volume is inversely related to
the pressure applied to it; in other words, the greater the pressure the less the volume - the greater the volume
the less the pressure. This relationship is constant for most gases within a moderate range of pressure. This
relationship is known as Boyle's Law.It is a physical law because it defines a cause-effect relationship, but it does
notexplain the relationship.
They Study Related or Similar Phenomena. (When we examine many related or similar phenomena, can we make
a generalization that covers them all?) A study of many related or similar phenomena is typically carried out to
determine whether a generalization or hypothesis can be formulated that accounts for, or explains, them all.
They Formulate General Hypotheses or Physical Theories. A theoretical generalization is formulated (if one is
found to be plausible). For example, the kinetic theoryof gas was formulated to explain what is documented in
Boyle'sLaw. According to this theory, gases are aggregates of discrete molecules that incessantly fly about and
collide with themselves and the wall of the container that holds them. The smaller the space they are forced to
occupy, the greater the number of collisions against the surfaces of the space.
They Seek to Test, Modify, and Refine Hypotheses. If a generalization is formulated, scientists test, modify, and
refine it through comprehensive study and experimentation, extending it to all known phenomena to which it
mayhave any relation, restricting its use where necessary, or broadening its use in suggesting and predicting new
phenomena.
When Possible, Scientists Seek to Establish General Physical Laws as well as Comprehensive Physical Theories.
General physical laws and comprehensive physical theories are broadly applicable in predicting and explaining the
physical world. The Law of Gravitation, for example, is a general physical law. It states that every portion of matter
attracts every other portion with a force directly proportional to the product of the two masses, and inversely
proportional to the square of the distance between the two. Darwin's Theoryof Evolution is a comprehensive
physical theory. It holds that all species of plants and animals develop from earlier forms by hereditary
transmission of slight variations in successive generations and that naturalselection determines which forms will
survive.

3. Essential Intellectual Standards
As a first step in understanding scientific thought and improving our skill in this discipline, we need a system
for intellectual intervention. A method for pre-empting weak thinking is necessary if we are to develop in our
ability to think scientifically with intellectual integrity. We need to take rational command of our cognitive
processes in order to rationally determine what to accept and what to reject. In short, we need standards for
thought,standards that guide us to consistently excellent thinking - standards we can count on to keep our thinking
on track, to help us mirror in our minds what is happening in reality, to reveal the truth in situations, to enable us
to determine how best to live our lives.
Understanding how to apply intellectual standard words appropriately to your biological thinking is essential
to improving you thinking in the discipline. The goal of this guide is to provide students with a conscious
foundation for thinking about intellectual standards, and the words that name them. Ultimately, such
consciousness will enable those proficient in the use of intellectual standard words to think more effectively in
every scientific domain, as well as, every academic discipline in which, or about which they think. In doing so, we
open the door to the development of a broad and integrated view of intellectual standards.
Critical thinkers routinely apply intellectual standards to the
elements of reasoning in order to develop intellectual traits.
The Standards The Elements Intellectual Traits
•Clarity •Purposes As we learn to
•Humility
•Relevance Must be applied to
•Questions develop
•Autonomy
•Accuracy •Points of View •Integrity
•Precision •Information •Courage
•Logicalness •Inferences •Persevereance
•Depth •Concepts •Confidence in
•Breadth •Implications Reason
•Significance •Assumptions •Empathy
•Fairness •Fairmindedness
There are at least nine intellectual standards important to conducting science and biology, as well as, everyday life.
These are: clarity, relevance, accuracy, precision, logic, depth, breadth, significance, and fairness. The importance
of these intellectual standards is that it would be unintelligible to claim that any instance of reasoning is both
sound and yet in violation of these standards. To see this, suppose a scientist were to claim that her/his reasoning
is sound regarding a biological claim, though at the same time admittedly unclear, imprecise, irrelevant, narrow,
superficial, illogical, trivial and unfair with respect to the claim they were making. Beginning with these nine
intellectual standards, the stage is set for conceptualizing intellectual standards (more broadly) and for
appreciating the essential role of intellectual standards in all human reasoning, especially science. An explication
of these essential intellectual standards follows:
Clarity: understandable, the meaning can be grasped; to free from confusion or ambiguity, to remove obscurities.
Clarity is a ‘gateway’ standard. If a statement is unclear, we cannot determine whether it is
accurate or relevant. In fact, we cannot tell anything about it because we don’t yet know what it is
saying. For example, the question “What can be done about species diversity in America?” is unclear.
In order to adequately address the question, we would need to have a clearer understanding of what
the person asking the question is considering the “problem” to be. A clearer question might be “What
can state legislatures do to limit the introduction and spread of invasive species in an effort to limit
impacts on native species?” Thinking is always more or less clear. It is helpful to assume that we do not
fully understand a thought except to the extent that we can elaborate, illustrate, and exemplify it.
Relevance: bearing upon or relating to the matter at hand; implies a close logical relationship with and importance to,
the matter under consideration.
A statement can be clear, accurate, and precise, but not relevant to the question at issue. For
example, students often think that the amount of effort they put into a course should be used in raising
their grade in a course. Often, however, “effort” does not measure the quality of student learning, and

4. when this is so effort is irrelevant to their appropriate grade. Thinking is always capable of straying
from the task, question, problem, or issue under consideration. It is useful to assume we have not fully
assessed thinking except to the extent that we have considered all issues, concepts, and information
relevant to it.
Accuracy: free from errors, mistakes or distortions; true, correct.
A statement can be clear but not accurate, as in “Most dogs weigh more than 300 pounds.”
Thinking is always more or less accurate. It is useful to assume that we have not fully assessed thinking
except to the extent that we have checked to determine whether it represents things as they really are
in the natural world.
Precision: exact to the necessary level of detail, specific.
A statement can be both clear and accurate, but not precise, as in “The patient is overweight.”
(We don’t know how overweight the patient is, one pound or 200 pounds.) Thinking is always more or
less precise. We can probably assume we do not fully understand an idea except to the extent that we
can explain it in detail. Quantitative data expressed by scientists are also evaluated according to
precision, as it is expected that the level of detail in the measuredand calculated numbers reflect and
are influenced by the tools used in the measurement. (Attention to rules of significant figures is essential!)
Logic: the parts make sense together, no contradictions; in keeping with principles of sound judgment and
reasonability.
When we think, we bring a variety of thoughts together into some order. When the combination
of thoughts is mutually supporting and makes sense in combination, the thinking is logical. When the
combination is not mutually supporting, is contradictory, or does not make sense, the combination is
not logical. Thinking can be more or less logical. It can be consistent and integrated. It can make sense
together or be contradictory or conflicting.
Depth: containing complexities and multiple interrelationships, implies thoroughness in thinking through the many
variable in the situation, context, idea, question.
A statement can be clear, accurate, precise, and relevant, but superficial (that is lacks depth). For
example statement “Without it you would die.” appears frequently on novice explanations in response
to anatomy and physiology questions, such as “Why is the liver important?” The response is clear,
accurate, precise, and relevant, but fails to appreciate the complexities in the problem. The thinking is
superficial at best. Thinking can either function at the surface of things or probe beneath that surface
to deeper matters and issues. We can assume we have not fully assessed a line of thinking except to
the extent that we have fully considered all the important complexities inherent in it.
Breadth: encompassing multiple viewpoints, comprehensive in view, wide-ranging and broadminded in perspective.
A line of reasoning may be clear, accurate, precise, relevant, and deep, but lack breadth even in
science (as in an argument from either the ‘lumper’ or ‘splitter’ viewpoint which details the
complexities in an issue, but only recognizes insights from one taxonomic perspective). Thinking can be
more or less broad-minded and breadth of thinking requires the thinker to reason insightfully within
more than one point of view or frame of reference. It is important, however, when assessing the
breadth of reasoning in scientific arguments that the reasoning is always based on scientific principles.
We can assume we have not fully assessed a line of thinking except to the extent that we have
determined how much breadth of thinking is required (and how much has in fact been exercised).
Significance: having importance, being of consequence; having considerable or substantial meaning.
When we reason through an issue, we want to concentrate on the most important information
(relevant to the issue) and take into account the most important ideas or concepts. Too often we fail to
recognize that, though many ideas may be relevant to an issue, they may not be equally important.
Similarly, we may fail to ask the most important questions and instead become mired in superficial
questions, questions of little weight. In high school, for example, few students focus on important
questions such as, “What does it mean to be an educated person? What do I need to do to become a
skilled biologist?” Instead, students tend to ask questions such as, “What do I need to do to get an ‘A’
in this course? How many pages does the lab report have to be? What do I have to do to have the
teacher ‘like’ me?” Thinking can be more or less significant. It can focus on what is most substantive,

5. what is of the highest consequence, what has the most important implications. or it can focus on the
trivial and superficial.
Fairness: free from bias, dishonesty favoritism, self-interest, deception or injustice.
We naturally think from our won perspective, from a point of view which tends to privilege our
position. Fairness implies the treating of all relevant viewpoints alike without reference to one’s own
feelings or interest. Because we tend to be biased in favor of our own viewpoint, it is important to keep
the intellectual standard of fairness at the forefront of our thinking. This is especially important in
science when we have a hypothesis that we would like to support, but the evidence may call on us to
see things we don’t want to see, or give something up we would rather hold onto. Thinking can be
more or less fair. Whenever opposing evidence is relevant to the situation or in the context, the
scientist is obligated to incorporate the evidence.
The Standards The Elements Intellectual Traits
•Clarity •Purposes •Humility
•Accuracy Must be applied to
•Questions As we learn to
•Autonomy
•Relevance •Points of View •Integrity
develop
•Logicalness •Information •Courage
•Breadth •Inferences •Persevereance
•Precision •Concepts •Confidence in
•Significance •Implications Reason
•Completeness •Assumptions •Empathy
•Fairness •Fairmindedness
•Depth
All Thinking can be Analyzed by Identifying its Eight Elements
The next step in understanding scientific and biological thought for the purposes of improvement is to recognize
what these standards would be applied to. Eight basic structures are present in all thinking: Whenever we think, we
think for a purpose within a point of view based on assumption leading to implications and consequences. We use
concepts, ideas, and theories to interpret data, facts, and experiences in order to answer questions, solve problems,
and resolve issues.
Careful analysis of any discipline helps illuminate theintellectual standards most necessary to
thinking well within it. To lay bare this logic, andkeeping in mind the elements or structures of thought
embedded in every discipline, wecan begin with the following questions:When we understand the
elements of reasoning, we realize that all subjects, all disciplines, have a fundamental logic defined by
the structures of thought embedded in them.
Therefore, to lay bare a subject’s most fundamental logic, we should begin with these questions:
What is the main purpose or goal of studying this subject? What are people in this field
trying to accomplish?
What kinds of questions do they ask? What kinds of problems do they try to solve?
What sorts of information or data do they gather?
What types of inferences or judgments do they typically make?
How do they do about gathering information in ways that are distinctive to this field?
What are the most basic ideas, concepts or theories in this field?
What do professionals in this field take for granted or assume?
What viewpoint is fostered in this field?
What implications follow from studying this discipline? How are the products of this field
used in everyday life?How should this study affect my view of the world? How is the world
impacted if this field of study is not understood?

6. Once we have answered these questions, we can then begin to apply intellectualstandards to the logic
of the discipline and to see how intellectual standards are mostusefully contextualized within it. To
exemplify this, we will introduce some of the waysin which intellectual standards are essential to careful
reasoning within two contexts: science, in general, and in biology specifically. We will first layout the
essential logic of the disciplineas seen through its component parts. We will then briefly comment on
some of theintellectual standards essential to skilled reasoning within that logic.
The Logic of Science
In the discipline of science in general, skilled practitioners of excellent reasoning and thinking would
then answer the questions above as follows:
Goals Scientists Pursue: Scientists seek to figure out how
the physical world operates through systematic
Purpose of
observation, experimentation, and analysis. By analyzing Scientific
Thinking
the physical world, they seek to formulate principles,
Scientific
laws, and theories useful in explaining natural Scientific Point
of View
Question at
Issue
phenomena, and in guiding further scientific study.
Questions Scientists Ask: How does the physical world
operate? What are the best methods for figuring things
out about the physical world? What are the barriers to Scientific Elements of
Scientific
Implications and Scientific
figuring things out about the physical world? How can Consequences
Thought
Information
we overcome those barriers?
Information Scientists Use: Scientists as a whole use
virtually any type of information that can be gathered
systematically through observation and measurement, Scientific
Scientific
Interpretation
Assumptions
and Inference
though most specialize in analyzing specific kinds of
information. To name just some of the information Scientific
Concepts
scientists use, they observe and examine plants,
animals, planets, stars, rocks, rock formations, minerals,
bodies of water, fossils, chemicals, phenomena in the
earth's atmosphere and cells. They also observe interactions between phenomena.
Judgments Scientists Make: Scientists make judgments about the physical world based on observations and
experimentation. These judgments lead to systematized knowledge, theories, and principles helpful in explaining
and understanding the world.
Concepts that Guide Scientists' Thinking: The most fundamental concepts that guidethe thinking of scientists are
1) physical world (of nature and all matter);
2) hypothesis (an unproved theory, proposition, or supposition tentatively accepted to explain certainfacts or to
provide a basis for further investigation);
3) experimentation (a systematicand operationalized process designed to figure out something about the
physicalworld); and
4) systematic observation (the act or practice of noting or recording facts orevents in the physical world). Other
fundamental concepts in science include: theory,law, scientific method, pure sciences, and applied sciences.
Key Assumptions Scientists Make: 1) There are laws at work in the physical world that can be figured out through
systematic observation and experimentation; 2) Much about the physical world is still unknown; 3) Through
science, the quality of life on earth can be enhanced.
Implications of Science: Many important implications and consequences have resulted from scientific thinking,
some of which have vastly improved the quality of life on earth, others of which have resulted in decreased quality
of life (e.g., the destruction of the earth's forests, oceans, natural habitats, etc.). One important positive
implication of scientific thinking is that it enables us to replace mythological thinking with theories and principles
based in scientific fact
The Scientific Point of View: Scientists look at the physical world and see phenomena best understood through
careful observation and systematic study. They see scientific study as vital to understanding the physical world and
replacing myth with scientific knowledge.

7. The Logic of Biology
In the more specific discipline of biology, skilled practitioners of excellent reasoning and thinking would
refine their answers to the questions above as follows:
Biological Goals: Biology is the scientific study of all life
forms.Its basic goal is tounderstand how living systems
Purpose of
work, including the fundamental processes and Scientific
Thinking
ingredients ofall life forms (i.e., 10,000,000 species in
Scientific
Scientific Point
fragile ecosystems). of View
Question at
Issue
Biological Questions: The questions biology is concerned
with are: What is life? How doliving systems work? What
are the structural and functional components of life
Scientific Elements
forms?What are the similarities and differences among Implications of Scientific
and Scientific Information
life forms at different levels (molecule,organelle, cell, Consequences
Thought
tissue, organ, organism, population, ecological
community, biosphere)?How can we understand the
biological unity of living matter?
Scientific
Biological Information: The kinds of information Scientific
Assumptions
Interpretation
and Inference
biologists seek are: information about thebasic units out
Scientific
of which life is constructed, about the processes by which Concepts
living systemssustain themselves, about the variety of
living systems, and about their structural andfunctional
components
Biological Judgments: Biochemists seek to make judgments about the complex processes ofmaintenance
and growth of which life basically consists.
Biological Concepts: There are a number of essential concepts to understand to understandthe logic of
biology: the concept oflevels of organization of life processes (at the molecularlevel, at the sub-cellular
particle level, at the cellular level, at the organ level, and at the levelof the total organism), the concept
of life structures and life processes, the concept of thedynamics of life, the concept of the unity oflife
processes amid a diversity of life forms,etc. ..
Biological Assumptions: Some of the key assumptions behind biological thinking are:that there are
foundations to life, that these foundations can be identified, studied,described, and explained; that it is
possible to use biological concepts to explain life; thatit is possible to analyze and discover the structure
and dynamics ofliving systems andtheir components; that all forms of life reproduce, grow, and respond
to changes in theenvironment; that there is an intricate and often fragile relationship between all
livingthings; that all life forms, no matter how diverse, have common characteristics: 1) theyare made
up of cells, enclosed by a membrane that maintains internal conditions differentfrom their surroundings,
2) they contain DNA or RNA as the material that carries theirmaster plan, and 3) they carry out a
process, called metabolism, which involves theconversion of different forms of energy by means of
which they sustain themselves.
Biological Implications: There are specific and general implications of the present logicof biology. The
specific implications have to do with the kind of questioning, the kind ofinformation-gathering and
information-interpreting processes being used by biologiststoday. For example, the state of the field
implies the importance of focusing questions andanalysis on the concepts above, of seeking key answers
at all levels of life systems. Thegeneral implications are that we have the knowledge, if not always the
will, to understand,maintain, and protect forms oflife.
Biological Point of View: The biological viewpoint is focused on all levels and forms oflife.lt sees all life
forms as consisting in structures and understood through describablefunctions. It seeslife processes at
the molecular level to be highly unified and consistent. Itseeslife processes at the whole-animal level to
be highly diversified.

8. Intellectual Standards Most Relevant to Reasoning Within the Disciplines Need to Be Articulated
As we have said, every field of study presupposes and strives to meet basic and essential intellectual
standards such as accuracy, relevance, and logicalness. However some intellectual standards may be
more important to reasoning well within any given field than other intellectual standards. Therefore, it is
up to those working within each discipline to articulate the intellectual standards most important to
reasoning through the problems and issues in the discipline, to detail how the standards should be
contextualized within the field.
By explicitly contextualizing intellectual standards within the disciplines, we raise our awareness of
them; we are more likely to consistently meet them; we are more likely to see when they are being
ignored or violated.
Application of Intellectual Standards in Biology
To comprehend how intellectual standards are essential to reasoning through questions and issues
within biology, consider the following examples, noting the intellectual standards in italics:
Reasoning within the logic of biology depends upon one's ability to formulate clearly and
precisely the questions at the heart of the discipline. Thus biologists must be ableto identify and
formulate seminal questions within the field.
Biologists must think comprehensively about the questions at the heart of the disciplineand in
making judgments about biological systems.
Biologists must think deeply about biological issues so as not to oversimplify their approach to
them.
Through their questions, biologists must draw links between biology and other modes of
thought, questions that seek relevant understandings from other subjects and disciplines (such
as chemistry, physics, ethics).
Biologists must ensure that the information they use in reasoning through biological issues is
accurate and relevant to the questions being addressed. They must include information about
all relevant parts of the interconnected system.
The dependability and validity of inferences made by biologists may be limited by the level of
detail present in instrumentation and meticulous methods used in collecting the supporting
information.
Though biologists draw from a large body of facts, theymust make many judgments utilizing
those facts, many of which come from observations and which lend themselves to more than
one reasonable interpretation. Biologists must therefore be careful to draw the most logical
inferences in observing living systems as they attempt to understand complexities in living
systems.
Biologists must also make logical judgments about how best to help guide public policy.
Biologists must have a rich and deep understanding of concepts outside biology which influence
or affect biological systems (concepts such as energy transformations, chemical dynamics,
climate, and human socio-economics) to make reasonable judgments about how to best
influence biological systems.
Biologists must be able to follow out the logical implications of their observations and
interpretations - decades and even centuries into the future.
Largely because of the prominence of the human species on the planet, because of its inordinately high
population in comparison with other mammals, the earth is an ecosystem out of balance. Couple this
with the fact that many human behaviors lead to devastatingeffects for other animals and plants living
on the planet and the importance ofbiological thinking seems apparent. Our very survival may well
depend upon it. Thusbiologists need to reason well through the most important logical implications
ofecosystems out of balance, and they need to educate people about the problem andwhat can be done
about it.

9. Scientific Thinking Requires Precision
To be precise in speaking of causal relationships, scientists must distinguish between different forms of such
relationships. For example, one set of distinctions essential to precise scientific thinking are the following: 1)
sufficient causes, 2) necessary causes, 3) necessary and sufficient causes, and 4) contributory causes.
To illustrate the difference, let us consider the relationship between smoking and lung cancer.
1) If smoking were a sufficient cause of lung cancer, everyone who smoked would get lung cancer.
2) If smoking were a necessary cause of lung cancer, only smokers would get lung cancer; non-smokers
would never get it.
3) If smoking were both a sufficient and necessary cause, everyone who smoked, and only those who
smoked would get lung cancer.
4) If smoking were a contributing cause of lung cancer, other things held constant, smokers would have a
higher rate of lung cancer than nonsmokers - which of course they do.
Experimental Thinking Requires Experimental Controls
To maintain control over all likely casual factors being examined, experimentersisolate each variable and
observe its effects on the phenomena being studied todetermine which factors are essential to the
causal effects.
Experiments Can Go Awry When Scientists Fail to Control for Confounded Variables. Often, a range of variables are
'associated' with a given effect, while only one of the variables is truly responsible for the effect. For example, it
has been found that in France, where people drink a lot of red wine, the incidence of heart attacks is lower than in
countries of northern Europe where red wine is less popular. Can we conclude from this statistical study that the
regular drinking of moderate amounts of red wine can prevent the occurrence of heart attacks? No, because there
are many other differences between the life styles of people in France and those in northern Europe, for example
diet, work habits, climate, smoking, commuting, air pollution, inherited pre· dispositions, etc. These other variables
are 'associated' or 'confounded' with the red wine variable. One or more of these confounded variables might be
the actual cause of the low incidence of heart attacks in France. These variables would have to be controlled in
some way before one could conclude that drinking red wine lowers the incidence of heart attacks.
A possible experimental design would be to compare Frenchmen who drink red wine with those who drink no
alcohol at all or drink beer - making sure that these groups do not differ on any other measurable variables. Or we
might study northern Europeans who drink red wine and see if the incidence of heart attack is lower among them
than among northern Europeans who do not drink red wine. We could also take a group of patients who have had
a heart attack, and instruct one half to drink a little red wine every day, and tell the other group to drink apple
juice. After a number of years we could compare the rate of incidence of heart attacks in the two groups.
Development of the Scientific Mind
Unreflective Challenged Thinker Beginning Practicing Scientific Advanced Accomplished
Scientific Thinker Thinker Scientific Thinker Scientific Thinker
Thinker • Recognize s the fact
that fails to think • Tries to improve • Recognizes the need for • Advancement is in • Good habits of
scientifically when
•Unaware of dealing with scientific
scientific thinking, but regular practice of accordance with scientific thought are
without regular scientific thought practice second nature
significant questions practice
problems in
thinking about
scientific issues

10. Intellectual DispositionsEssential to Scientific Thinking
To become fair-minded, intellectually responsible scientific thinkers, we mustdevelop intellectual virtues or
dispositions. These attributes are essential toexcellence of scientific thought.
They determine with what insight and integrity we think. This section containsbrief descriptions of the intellectual
virtues, along with related questions thatfoster their development.
Intellectual humility is knowledge of ignorance, sensitivity to what you knowand what you do not know. It implies
being aware of your biases, prejudices, selfdeceptivetendencies and the limitations of your viewpoint. Questions
that fosterintellectual humility in scientific thinking include:
• What do I really know about the scientific issue I am raising?
• To what extent do my prejudices or biases influence my ability to thinkscientifically?
• How do the beliefs I have uncritically accepted keep me from thinkingscientifically?
Intellectual courage is the disposition to question beliefs you feel strongly about.It includes questioning the beliefs
of your culture and the groups to which youbelong, and a willingness to express your views even when they are
unpopular.Questions that foster intellectual courage include:
• To what extent have I analyzed the beliefs I hold which may impede my abilityto think scientifically?
• To what extent have I demonstrated a willingness to give up my beliefs whensufficient scientific evidence is
presented against them?
• To what extent am I willing to stand up against the majority (even thoughpeople ridicule me)?
Intellectual empathy is awareness of the need to actively entertain views thatdiffer from our own, especially those
we strongly disagree with. It is to accuratelyreconstruct the viewpoints and reasoning of our opponents and to
reason frompremises, assumptions, and ideas other than our own. Questions that fosterintellectual empathy
include:
• To what extent do I accurately represent scientific viewpoints I disagree with?
• Can I summarize the scientific views of my opponents to their satisfaction?
• Can I see insights in the scientific views of others and prejudices in my own?
Intellectual integrity consists in holding yourself to the same intellectualstandards you expect others to honor (no
double standards). Questions that fosterintellectual integrity in scientific thinking include:
• To what extent do I expect of myself what I expect of others?
• To what extent are there contradictions or inconsistencies in the way I dealwith scientific issues?
• To what extent do I strive to recognize and eliminate self-deception whenreasoning through scientific issues?
Intellectual perseverance is the disposition to work your way through intellectualcomplexities despite the
frustration inherent in the task. Questions that fosterintellectual perseverance in scientific thinking include:
• Am I willing to work my way through complexities in a scientific issue or do Itend to give up when I experience
difficulty?
• Can I think of a difficult scientific problem concerning which I havedemonstrated patience and determination in
working through its difficulties?
Confidence in reason is based on the belief that one's own higher interests andthose of humankind at large are
best served by giving the freest play to reason.It means using standards of reasonability as the fundamental
criteria by whichto judge whether to accept or reject any belief or position. Questions that fosterconfidence in
reason when thinking scientifically include:
• Am I willing to change my position when the scientific evidence leads to amore reasonable position?
• Do I adhere to scientific principles and evidence when persuading others ofmy position or do I distort matters to
support my position?
• Do I encourage others to come to their own scientific conclusions or do I try toforce my views on them?
Intellectual autonomy is thinking for oneself while adhering to standards ofrationality. It means thinking through
issues using one's own thinking rather thanuncritically accepting the viewpoints of others. Questions that foster
intellectualautonomy in scientific thinking include:
• Do I think through scientific issues on my own or do I merely accept thescientific views of others?
• Having thought through a scientific issue from a rational perspective, am Iwilling to stand alone despite the
irrational criticisms of others?

11. The Problem of Pseudo-Scientific and Unscientific Thinking
Unscientific and pseudo-scientific thinking come from the unfortunate fact that humans do not naturally
think scientifically, though they often think they do. Furthermore, we become explicitly aware of our
unscientific thinking only if trained to do so. We do not naturally recognize our assumptions, the
unscientific way we use information, the way we interpret data, the source of our concepts and ideas,
the implications of our unscientific thought. We do not naturally recognize our unscientific perspective.
As humans we live with the unrealistic but confident sense that we have fundamentally figured out the
true nature of things, and that we have done this objectively. We naturally believe in our intuitive
perceptions - however inaccurate. Instead of using intellectual standards in thinking, we often use self-
centered psychological standards to determine what to believe and what to reject. Here are the most
commonly used psychological standards in unscientific human thinking.
"IT'S TRUE BECAUSE I BELIEVE IT.” I assume that what I believe is true even though I have never
questioned the basis for my beliefs.
"IT'S TRUE BECAUSE WE BELIEVE IT.”I assume that the dominant beliefs within the groups to which I
belong are true even though I have never questioned the basis for many of these beliefs.
"IT'S TRUE BECAUSE I WANT TO BELIEVE IT.” I believe in, for example, accounts of behavior that put me
(or the groups to which I belong) in a positive rather than a negative light even though I have not
seriously considered the evidence for the more negative account. I believe what "feels good;' what
supports my other beliefs, what does not require me to change my thinking in any significant way, what
does not require me to admit T have been wrong.
"IT'S TRUE BECAUSE I HAVE ALWAYS BELIEVED IT.” I have a strong desire to maintain beliefs that I have
long held, even though I have not seriously considered the extent to which those beliefs are justified,
given the evidence.
"IT'S TRUE BECAUSE IT IS IN MY INTEREST TO BELIEVE IT.” I hold fast to beliefs that justify my getting
more power, money, or personal advantage even though these beliefs are not grounded in sound
reasoning or evidence.
Since humans are naturally prone to assess thinking in keeping with the above criteria, it is not
surprising that unscientific thinking flourishes in our society.