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Chapter 4
Critical Thinking Skills
Objectives
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Identify the qualities of a critical thinker
Identify assumptions, ethics, and values in written works
Discern fallacies in arguments
Control psychologic impediments to sound reasoning
Recognize the effects of authors’ background belief on reasoning
Present valid facts, evidence, and statistics, and rhetoric
What is Critical Thinking?
 Many definitions have been give for it
 One such is emancipation, which means freedom from restraint or influence
 Things that restrain or influence people can be personal, institutional, or
environmental
 Emancipatory learning means that the learners become aware of the forces
that have created the circumstances of their lives and take action to change
them
 Another definition focuses on the use of morality and virtues, making wise
judgments about aspects of one’s life, and recognizing the impacts of these
judgments will have on others
 Some stress the importance of recognizing reality in the context of cultural
elements and the process of trying to create order in a changing world.
 Learning how to live and work in this changing world makes critical thinking
more important than ever
 When we speak of making wise decisions, we are judging decisions made
within the framework of a value system that is universally understood.
 It is equated with logical reasoning abilities and reflective judgment
The Qualities of a Critical Thinker
 Critical thinkers are valued for their ability to look at a situation from a variety
of perspectives
 Critical thinkers need to possess certain characteristics
 Humane – presence of heart and mind; able to balance compassion with
realism
 Analytical – means finding evidence in unclear and confusing situations;
rushing into a plan without examining the ramifications of that action can be
very dangerous
 Rational – rational thinkers recognize reality; they can discern what is factual
and true from what is opinion or misinformation; recognize the difference
between what is true and what we wish were true
The Qualities of a Critical Thinker
 Open-minded – disagreements are not uncommon, but a heated confrontation
can be diffused by the willingness of the critical thinker to listen and
understand
 Systematic – patience and organization allow a person time to gather
evidence, test ideas, and systemically work through tough problems and
complex questions; resist the desire to reach a solution before all the facts are
in
 Inquisitive – this nature will lead a person to seek knowledge from many
sources; this is a quality found in effective learners
Factors That Hinder Critical Thinking
 Background beliefs
 Religious training, attitudes of society, cultural traditions, and teaching from
parents and school teachers form our background beliefs
 These beliefs are the stabilizing forces that guide us and the glue that holds
society together
 They are the most deeply ingrained beliefs and thus the most intensely
defended
 Faulty reasoning
 Occurs when biased or false information is stated as fact
 This is the aim of advertising
 Endorsements by a public figure will lend credibility to the advertiser's
claims that the product is the best
 Ultimate goal is persuading you to by the product
 We reason that statistics are accurate and unquestionable
 Group loyalty
 There is a natural cohesiveness in a social group called the herd instinct
 All members follow a predetermined set of behaviors; there is a desire to
gain status within the group
 Success in everyday life depends to a great extent on being accepted by
your social group
 Instinct makes us aware that our survival depends on the survival of the
group
 Frozen mind set
 Centered at maintaining status quo
 Early in childhood we learn to go along with the group and base our actions
on group approval
 This is so deeply ingrained in some people that no amount of evidence will
change their minds
Factors That Hinder Critical Thinking
 Emotional baggage
 Almost everyone has issues they feel strongly about and will defend
vigorously
 Some issues that many have emotional ties to are abortion, gun control, the
death penalty, censorship, etc
 When you have identified the issue that causes you anger or discomfort, it
helps to seek out information on both sides of the argument
 Learn why those whose position runs counter to yours feel the way they do
and on what basis their opinions rest
Becoming a Critical Thinker
 Humility
 The first step in becoming a critical thinker is to make a humble approach
and be open to learning
 It is acceptable, even admirable, to admit that you are not sure or that you
need more information
 Respect for others
 To live peacefully in a diverse society, we must be tolerant of many different
cultures and traditions
 Self-awareness
 Recognize the things that make you glad, the things that make you sad,
and the things that make you mad
 As you grow and develop in your critical thinking ability, the issues that
bring forth an emotional response will become more evident, and you will
be able to deal with them more effectively
 Honing your Skills
 Practice helps you to develop your skills in critical thinking
 As issues arise, consciously and deliberately look at them for several points
of view, and weigh the evidence on the most reliable and convincing basis
 Will enable you to resist making instant judgments and taking rash actions
Conclusion
 Critical thinking is a term used to describe thinking based on a universal value
system
 Characteristics are compassion, patience, respect for others’ opinions, open
mindedness, and the ability to be analytical
 As a health care provider, you will be confronted with many issues requiring
logical judgment and rational action
 Critical thinkers will be aware of their values and know the reason and
consequences of the action taken
Chapter 5
The History of Medicine
Prehistoric and Ancient Medicine
 Disease was present on earth long before human life
 We can only speculate about the human practice of prehistoric medicine
 Egyptian mummies and radiographic images of the ‘ice man” show
characteristics of arteriosclerosis, pneumonia, stones, parasites, cavities,
abscesses, tubercular disease, etc.
 Until well into the 19th century, medical treatment was intertwined with religion
and magic
 Some cultures treated their sick, elderly, and disabled with kindness
 Other cultures, during times of famine, sent the elders out into unsheltered
environment
 Some even killed and ate disabled tribe members
 Disease was thought to be caused by gods and spirits, and magic was used to
drive away evil forces
 The Mesopotamians studied hepatoscopy, which is the detailed examination of
the liver
 They believed the liver was the seat of life and the collecting point of blood
 Even though gods and magic still played an important role in medicine, rational
thought about nature’s relationship to health began to increase
 The ancient Hebrews still considered disease to be divine punishment and a
mark of sin
 Hebrew medicine was influenced by the Greeks around the fourth century BC
with an emphasis placed on anatomy and physiology, diet, massage, and
drugs
 Disease was considered an imbalance of the four humors of the body: phlegm,
blood, yellow bile, and black bile
Ancient Egypt
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The deities of ancient Egypt were associated with health, illness, and death
Isis was the healing goddess
Hathor was the mistress of heaven and the proctor of women during childbirth
Keket ensured fertility
The ancient Egyptians linked anatomy and physiology with theology; each
body part had a special deity as its proctor
Ancient India
 They believed (as do many contemporary Indians) that life was an eternal
cycle of creation, preservation, and destruction
 Their religion allowed secular medicine and sound, rational health care
practices
 They detected diabetes by the sweetness of the patient’s urine and treated
snakebites with tourniquets.
 They also performed cesarean sections
Ancient China
 Harmony was considered to be a delicate balance between yin and yang, and
Tao was considered “the way”
 Illness was seen as a disregard for Tao or acting contrary to natural laws
 Chinese medicine focused on the prevention of disease
 Had developed an inoculation against smallpox by the eleventh century
 Believed in five methods of treatment
 Cure the spirit
 Nourish the body
 Give medications
 Treat the whole body
 Use acupuncture and moxibustion*
 Powdered plant is burned on the skin
Ancient Greece
 In the sixth century BC, Greeks built the healing temples of Asclepios in
Thessaly
 Temples contained a statue of a god to whom gifts were often given as a sign
of worship
 Abaton – building considered an incubation site where the cure took place;
patient went to sleep there and was cured by the god
 Healing rituals began after sundown and often involved fasting or abstinence
from
certain food or wine
Pre-Hippocratic Medicine
 Heraclitus (540-480 BC) – believed fire was the principal element of life
 Anaximenes (circa 546 BC) – believed air was the element necessary for life
 Anaximander (610-547 BC) – believed that all living creatures originated in
water
 Thales (625-547 BC)- professed that the basic element in animal and plant life
was water
 By the sixth century BC, earth, air, fire, and water were accepted as the basic
components of life on earth
Hippocrates
 Hippocraties established himself as the “father of medicine”
 He taught that one should observe all, study the patient rather than the
disease, evaluate honestly, and assist nature
 He employed few drugs and relied upon the healing powers of nature
 His writings addressed mental illness, anxiety, and depression
Christianity
 The dawn of Christianity changed many attitudes about medicine
 Christians sought to bring the “healing message of Christ” to those in need
 The Church dominated medicine during the Dark Ages, and practices involved
prayer, exorcism, holy oil, relics of saints, supernaturalism, and superstition
 At the same time, medical schools separate from Church were established and
soon became part of major universities
The Renaissance
 Paracelsus, the “father of pharmacology”, combined alchemy with the
treatment of disease to produce a new science
 Jean Fernel professed that physiology, pathology, and therapeutics were the
standard disciplines of medicine
 Andreas Versallus, his dissections and drawings prompted his designation as
the “father of anatomy”
 Ambroise Pare was a forerunner in clinical surgery
 Jan Baptisa van Helomnt made the first measurement of the relative weight of
urine
 Galileo presented the laws of motion in a mathematical manner
 Isaac Newton discovered gravity
 William Harvey found that there is a continuous circulation of blood in a
contained body system
 Christian Huygens developed the centigrade system for measuring
temperature
 Gabriel Daniel Fahrenheit developed a self-named system for temperature
measurement
 Marcello Malpighi and Anton van Leeuwenhoek were forerunners in the
invention of the microscope
 Quinine was discovered as a treatment for malaria
The Eighteenth Century
 Albrecht von Haller studied the nervous system, discovered the relationship of
the brain cortex, peripheral nerves, and became the founder of modern
physiologic theory
 Giovanni Battista Morgagni, “the father of pathology”, correlated anatomy with
pathology
 Edward Jenner formulated the smallpox vaccination
The Nineteenth Century
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Autopsies were the major focus of medicine
Rudolf Virchow professed that “all cells come from other cells”
Claude Bernard discovered the principle of homeostasis
J. Marion Sims laid the foundation for gynecology and founded the Women’s
Hospital of the State of New York; also invented the Sims’ position and later
the speculum and catheter
Anesthesia entered surgery, procedures multiplied in number and complexity
Joseph Lister discovered that bacteria were often the origin of disease and
infection
The foundation for modern genetics was laid by Gregor Mendel in 1886
November 8, 1895, Conrad Wilhelm Roentgen discovered and described xrays
The Twentieth Century
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Electron microscope invented in 1930
The Salk vaccine virtually eliminated polio
Major organ transplants
Artificial hips and knees
Plastic surgery
CT, MRI, digital radiography, nuclear medicine, sonography, benefit from the
merging of computers with imaging technology
The Twenty-First Century
 The second millennium AD continues with a rapid expansion of technology
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and information
The accumulation of knowledge accelerates at an unprecedented pace,
doubling every 15 to 18 months
Research into genetics has greatly expanded our knowledge about heredity
with the deciphering of the DNA code
The International Space Station is doing research in the fields of human
physiology and pharmacology
Biotechnology is opening new frontiers in treatment on a daily basis
Health and Disease
 The World Health Organization defines health as “a state of complete physical,
mental, and social well-being, and not merely the absence of disease or
infirmity”
 Sheldon defines disease as “the pattern of response of a living organism to
some form of injury”; “should be viewed as disordered function rather than only
as altered structure”
Health and Disease
 Measuring health status is a time-consuming, complicated, and often
subjective process
 We rely on data that indicate rates of mortality (death rate) and morbidity
(occurrence of disease or conditions)
 Its apparent that Americans are live longer and have fewer acute episodes of
illness than ever before, but we have more chronic conditions than ever:
arthritis, respiratory diseases, heart and circulatory problems, cancer,
allergies, alcohol and drug abuse, etc
Mortality
 The Center for Disease Control (CDC), through its National Center for Health
Statistics (NCHS), gathers and publishes data on life and death statistics in the
United States
 The mission of the CDC is to promote health and quality of life by preventing
and controlling disease, injury, and disability
15 Leading Causes of Death in the U.S.
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Cancer
Heart disease
Cerebrovascular accident (stroke)
Chronic lower respiratory diseases
Accidents (unintentional injuries, including motor vehicle fatalities
Diabetes mellitus
Influenza and pneumonia
Alzheimer’s disease
Nephritis (kidney disease)
Septicemia (blood infection)
Suicide
Chronic liver disease and cirrhosis
Hypertension (high blood pressure)
Parkinson’s disease
Pneumonitis (inflammation of the lungs)
General Population Mortality
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Ages 1 to 44 – leading cause of death is accidents
Ages 45 to 64 – leading cause of death is cancer
Ages over 65 years – leading cause of death is heart disease
HIV mortality has declined by more than 70% since 1995
HIV no longer ranks among the top 15 causes of disease in the U.S.
Over 40,000 – number of annual deaths in women from breast cancer
Over 39,000 – number of annual deaths in men from prostrate cancer
Special Causes of Death
 Drugs
 Death rate is approximately 4.3 per 100,000 persons
 Death rate among males is more than twice the rate of females
 Death rate for the black population is nearly twice that of the white
population
 Alcohol
 Death rate is approximately 6.8 per 100,000 persons
 Death rate among males is 3.5 times higher than the death rate for females
 Death rate for blacks is nearly 2.5 times higher than the death rate for
whites
Morbidity
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Previously defined as the rate of occurrence of disease or conditions
Primary causes of disablement, medical intervention, health care
expenditures, and overall lack of wellness in the United States:
Obesity
Mental and emotional disorders, including alcohol and drug abuse
Diseases of the cardiovascular system
Arthritis
Epilepsy
Cerebral palsy
Multiple sclerosis
Parkinson’s disease
Muscular dystrophy
Hearing and visual impairments
Mental retardation
Diabetes mellitus
Cancer
Life Expectancy
 Overall U.S. life expectancy is 77.6 years
 Female to male gap has closed to 5.3 years
 Averages in the 21st century
 White females: 80.5 years
 Black females: 76.1 years
 White males: 75.4 years
 Black males: 69.2 years
 At age 65, life expectancy is as follows:
 All Americans: an additional 18 years
 All males: an additional 16 years
 All females: an additional 20 years
Emerging Infectious Diseases
 Emerging infectious diseases – refers to diseases of infectious origin whose
incidence in humans has either increased within the past two decades or
threatens to increase in the near future
 Modern medicine has eradicated smallpox and is nearing the elimination of
polio
 Other targeted diseases include:
 Guinea worm
 Onchocerciasis (river blindness)
 Syphilis
 Rabies
 Measles
 TB
 Leprosy
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Epidemic – a widespread infectious disease within a given geographical area
Pandemic – an infectious disease of global proportions
Infectious diseases account for 25% of all visits to physicians each year
Antimicrobial agents are the second most frequently prescribed class of drugs
in the U.S.