Scientific thinking

Scientific thinkingScientific thinking

Prof. Vajira WeerasingheProf. Vajira WeerasingheProfessor of PhysiologyProfessor of Physiology

Department of PhysiologyDepartment of Physiology

Faculty of Medicine Faculty of Medicine

University of Peradeniya University of Peradeniya

ObjectivesObjectives

1.1. Define “science”Define “science”

2.2. State the main goal of scienceState the main goal of science

3.3. Differentiate “science” from Differentiate “science” from “technology” “technology”

4.4. Define “scientific method”Define “scientific method”

5.5. Describe the steps in scientific Describe the steps in scientific methodmethod

What is science ?What is science ? Is derived from the Latin word scientia for knowledge Is derived from the Latin word scientia for knowledge

The state of knowingThe state of knowing

Knowledge as distinguished from ignorance or misunderstandingKnowledge as distinguished from ignorance or misunderstanding

The systematic study of the natural world The systematic study of the natural world

Systematically acquired knowledge that is verifiableSystematically acquired knowledge that is verifiable

The observation, identification, description, experimental investigation, and The observation, identification, description, experimental investigation, and theoretical explanation of phenomena theoretical explanation of phenomena

It is a method used by humans to try to make sense of the world (and It is a method used by humans to try to make sense of the world (and universe) in which they liveuniverse) in which they live

http://www.sciencedaily.com/

Main goal of scienceMain goal of science The main goal of science is to acquire The main goal of science is to acquire

knowledge about the world knowledge about the world

To explain the natural world as we observe it as To explain the natural world as we observe it as much as possible and to search for ways of much as possible and to search for ways of applying such knowledge for the benefit of applying such knowledge for the benefit of humanity humanity

Different branches of science Different branches of science PURE SCIENCE PURE SCIENCE

The seeking of information for its own sakeThe seeking of information for its own sake The pursuit of knowledge for the sake of knowledgeThe pursuit of knowledge for the sake of knowledge

APPLIED SCIENCE APPLIED SCIENCE The seeking of information that is of immediate use The seeking of information that is of immediate use

and benefit and benefit

Related terms Related terms TechnologyTechnology

originates from the Greek word tekhnologia and the Latin word technologia which means an approach to doing something systematically

It is the usage and knowledge of tools, techniques, crafts, systems or methods of organization

PhilosophyPhilosophy is a branch of knowledge that study

general problems pertaining to existence, knowledge, justice, truth, beauty, law, validity, mind and language

TechnologyTechnology Compared to “science”, the term , “technology” Compared to “science”, the term , “technology”

is still new as it is only used since the 18is still new as it is only used since the 18thth centurycentury

Scientific medicine Scientific medicine Medicine is the science and art of healing Medicine is the science and art of healing

humanshumans

Medical science or scientific basis of medicineMedical science or scientific basis of medicine

Medical technologyMedical technology

What is scientific method ?What is scientific method ? Refers to a body of techniques for investigating phenomena, Refers to a body of techniques for investigating phenomena,

acquiring new knowledge, or correcting and integrating previous acquiring new knowledge, or correcting and integrating previous knowledgeknowledge

To be termed scientific, a method of inquiry must be based on To be termed scientific, a method of inquiry must be based on gathering gathering observableobservable, , empiricalempirical and and measurablemeasurable evidence subject to evidence subject to specific principles of reasoningspecific principles of reasoning

A scientific method consists of the collection of data through A scientific method consists of the collection of data through observationobservation and and experimentationexperimentation, and the formulation and testing of , and the formulation and testing of hypotheseshypotheses

These steps must be repeatable, to predict future resultsThese steps must be repeatable, to predict future results

Scientific inquiry is generally intended to be as Scientific inquiry is generally intended to be as objectiveobjective as possible, as possible, to reduce biased interpretations of resultsto reduce biased interpretations of results

Related termsRelated terms EmpiricalEmpirical

information gained by means of observation, experience, or information gained by means of observation, experience, or experiment experiment

In the scientific method all evidence must be empirical, or In the scientific method all evidence must be empirical, or empirically based, that is, dependent on evidence or empirically based, that is, dependent on evidence or consequences that are observable by the sensesconsequences that are observable by the senses

Empirical data is data that is produced by an experiment or Empirical data is data that is produced by an experiment or observationobservation

HypothesisHypothesis A suggested explanation for an observable phenomenon, or A suggested explanation for an observable phenomenon, or

a reasoned proposal predicting a causal correlation among a reasoned proposal predicting a causal correlation among multiple phenomenamultiple phenomena

Inductive vs Deductive logic Inductive vs Deductive logic INDUCTIVE REASONING: INDUCTIVE REASONING:

From a specific case to the general principle From a specific case to the general principle Sparrows are birdsSparrows are birds They have wings and can flyThey have wings and can fly Robins, flamingos, owls, and eagles areRobins, flamingos, owls, and eagles are

birds, have wings and can fly birds, have wings and can fly From this you might induct From this you might induct

that "ALL BIRDS CAN FLY." that "ALL BIRDS CAN FLY."

DEDUCTIVE REASONING: DEDUCTIVE REASONING: From the general case to the specific From the general case to the specific All birds have feathered wingsAll birds have feathered wings We know that sparrows have feathered wingsWe know that sparrows have feathered wings Therefore, we can deduce that "Sparrows are birds.“Therefore, we can deduce that "Sparrows are birds.“

Inductive vs Deductive logicInductive vs Deductive logic The problem with this is the "inductive leap“The problem with this is the "inductive leap“

When you make the jump from many observations to When you make the jump from many observations to saying that your observation is true in all cases, saying that your observation is true in all cases, you are making a generalization that might not be you are making a generalization that might not be correct every time correct every time

Although generalizations can be useful, the wise Although generalizations can be useful, the wise scientist is always aware that there may be scientist is always aware that there may be EXCEPTIONS to the general ruleEXCEPTIONS to the general rule

and to the possibility that the "general rule“ might and to the possibility that the "general rule“ might eventually be found to be wrongeventually be found to be wrong

Inductive vs Deductive logicInductive vs Deductive logic Let's take an example Let's take an example You suddenly come upon an ostrichYou suddenly come upon an ostrich

It has wings, and all the other characteristics It has wings, and all the other characteristics you'd ascribe to a bird--BUT IT CANNOT FLY!you'd ascribe to a bird--BUT IT CANNOT FLY!

Or a bat, it can fly, has wings BUT NOT A BIRDOr a bat, it can fly, has wings BUT NOT A BIRD

Does this mean that your general rule is always wrong? NoDoes this mean that your general rule is always wrong? No

But it does mean that there are exceptions, and you must be But it does mean that there are exceptions, and you must be ready to find them!ready to find them!

The human mind is creative in its inductive reasoning, but it is The human mind is creative in its inductive reasoning, but it is not omniscient (all-knowing) or infallible!not omniscient (all-knowing) or infallible!

This is why scientists use deductive reasoning in their scientific This is why scientists use deductive reasoning in their scientific endeavors. Such reasoning is less susceptible to this type of errorendeavors. Such reasoning is less susceptible to this type of error

LogicLogicpremise, inference and conclusion premise, inference and conclusion

All insects have wings (premise)All insects have wings (premise)Woodlice are insects (premise)Woodlice are insects (premise)Therefore woodlice have wings (conclusion)Therefore woodlice have wings (conclusion)

All fish live in the sea (premise)All fish live in the sea (premise)Dolphins are fish (premise)Dolphins are fish (premise)Therefore dolphins live in the sea (conclusion)Therefore dolphins live in the sea (conclusion)

All basketballs are round.The Earth is round.Therefore, the Earth is a basketball.

Hypothetic-deductive methodHypothetic-deductive method

The formulation of an hypothesis (a tentative The formulation of an hypothesis (a tentative answer to a question) and the execution of answer to a question) and the execution of experiments from which one may deduce a experiments from which one may deduce a general answer to the hypothesisgeneral answer to the hypothesis

Steps in scientific methodSteps in scientific method

1.1. Observation Observation

2.2. Asking a critical question Asking a critical question

3.3. Developing a hypothesis Developing a hypothesis

4.4. Making a prediction that can be tested Making a prediction that can be tested

5.5. Performing experiments to test the prediction Performing experiments to test the prediction

6.6. Collecting and analyzing data Collecting and analyzing data

7.7. Making a logical conclusion based on Making a logical conclusion based on experimental resultsexperimental results

Scientific methodScientific method Observing and stating a research problemObserving and stating a research problem Forming a hypothesis: gather information about Forming a hypothesis: gather information about

the observed phenomenon and make a the observed phenomenon and make a hypothesishypothesis

Testing the hypothesisTesting the hypothesis Experimentation Experimentation

VariableVariable OutcomeOutcome Control experimentControl experiment Recording and analysing resultsRecording and analysing results Forming a conclusion Forming a conclusion

http://www.nobelprize.org/

http://www.nobelprize.org/nobel_prizes/medicine/laureates/1905/




No amount of experimentation can ever prove me right; a single

experiment can prove me wrong.

Albert Einstein