Scientific thinking


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Scientific thinking

  1. 1. Scientific thinking Prof. Vajira Weerasinghe Professor of Physiology Department of Physiology Faculty of Medicine University of Peradeniya
  2. 2. Objectives <ul><li>Define “science” </li></ul><ul><li>State the main goal of science </li></ul><ul><li>Differentiate “science” from “technology” </li></ul><ul><li>Define “scientific method” </li></ul><ul><li>Describe the steps in scientific method </li></ul>
  3. 3. What is science ? <ul><li>Is derived from the Latin word scientia for knowledge </li></ul><ul><li>The state of knowing </li></ul><ul><li>Knowledge as distinguished from ignorance or misunderstanding </li></ul><ul><li>The systematic study of the natural world </li></ul><ul><li>Systematically acquired knowledge that is verifiable </li></ul><ul><li>The observation, identification, description, experimental investigation, and theoretical explanation of phenomena </li></ul><ul><li>It is a method used by humans to try to make sense of the world (and universe) in which they live </li></ul>
  4. 5. Main goal of science <ul><li>The main goal of science is to acquire knowledge about the world </li></ul><ul><li>To explain the natural world as we observe it as much as possible and to search for ways of applying such knowledge for the benefit of humanity </li></ul>
  5. 7. Different branches of science <ul><li>PURE SCIENCE </li></ul><ul><ul><li>The seeking of information for its own sake </li></ul></ul><ul><ul><li>The pursuit of knowledge for the sake of knowledge </li></ul></ul><ul><li>APPLIED SCIENCE </li></ul><ul><ul><li>The seeking of information that is of immediate use and benefit </li></ul></ul>
  6. 8. Related terms <ul><li>Technology </li></ul><ul><ul><li>originates from the Greek word tekhnologia and the Latin word technologia which means an approach to doing something systematically </li></ul></ul><ul><ul><li>It is the usage and knowledge of tools, techniques, crafts, systems or methods of organization </li></ul></ul><ul><li>Philosophy </li></ul><ul><ul><li>is a branch of knowledge that study general problems pertaining to existence, knowledge, justice, truth, beauty, law, validity, mind and language </li></ul></ul>
  7. 9. Technology <ul><li>Compared to “science”, the term , “technology” is still new as it is only used since the 18 th century </li></ul>
  8. 13. Scientific medicine <ul><li>Medicine is the science and art of healing humans </li></ul><ul><li>Medical science or scientific basis of medicine </li></ul><ul><li>Medical technology </li></ul>
  9. 14. What is scientific method ? <ul><li>Refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge </li></ul><ul><li>To be termed scientific, a method of inquiry must be based on gathering observable , empirical and measurable evidence subject to specific principles of reasoning </li></ul><ul><li>A scientific method consists of the collection of data through observation and experimentation , and the formulation and testing of hypotheses </li></ul><ul><li>These steps must be repeatable, to predict future results </li></ul><ul><li>Scientific inquiry is generally intended to be as objective as possible, to reduce biased interpretations of results </li></ul>
  10. 16. Related terms <ul><li>Empirical </li></ul><ul><ul><li>information gained by means of observation, experience, or experiment </li></ul></ul><ul><ul><li>In the scientific method all evidence must be empirical, or empirically based, that is, dependent on evidence or consequences that are observable by the senses </li></ul></ul><ul><ul><li>Empirical data is data that is produced by an experiment or observation </li></ul></ul><ul><li>Hypothesis </li></ul><ul><ul><li>A suggested explanation for an observable phenomenon, or a reasoned proposal predicting a causal correlation among multiple phenomena </li></ul></ul>
  11. 17. Inductive vs Deductive logic <ul><li>INDUCTIVE REASONING: From a specific case to the general principle </li></ul><ul><ul><li>Sparrows are birds </li></ul></ul><ul><ul><li>They have wings and can fly </li></ul></ul><ul><ul><li>Robins, flamingos, owls, and eagles are birds, have wings and can fly </li></ul></ul><ul><ul><li>From this you might induct that &quot;ALL BIRDS CAN FLY.&quot; </li></ul></ul><ul><li>DEDUCTIVE REASONING: From the general case to the specific </li></ul><ul><ul><li>All birds have feathered wings </li></ul></ul><ul><ul><li>We know that sparrows have feathered wings </li></ul></ul><ul><ul><li>Therefore, we can deduce that &quot;Sparrows are birds.“ </li></ul></ul>
  12. 18. Inductive vs Deductive logic <ul><li>The problem with this is the &quot;inductive leap“ </li></ul><ul><li>When you make the jump from many observations to saying that your observation is true in all cases, you are making a generalization that might not be correct every time </li></ul><ul><li>Although generalizations can be useful, the wise scientist is always aware that there may be EXCEPTIONS to the general rule </li></ul><ul><li>and to the possibility that the &quot;general rule“ might eventually be found to be wrong </li></ul>
  13. 19. Inductive vs Deductive logic <ul><li>Let's take an example </li></ul><ul><li>You suddenly come upon an ostrich It has wings, and all the other characteristics you'd ascribe to a bird--BUT IT CANNOT FLY! </li></ul><ul><li>Or a bat, it can fly, has wings BUT NOT A BIRD </li></ul><ul><li>Does this mean that your general rule is always wrong? No </li></ul><ul><li>But it does mean that there are exceptions, and you must be ready to find them! </li></ul><ul><li>The human mind is creative in its inductive reasoning, but it is not omniscient (all-knowing) or infallible! </li></ul><ul><li>This is why scientists use deductive reasoning in their scientific endeavors. Such reasoning is less susceptible to this type of error </li></ul>
  14. 20. Logic premise, inference and conclusion <ul><li>All insects have wings (premise) Woodlice are insects (premise) Therefore woodlice have wings (conclusion) </li></ul><ul><li>All fish live in the sea (premise) Dolphins are fish (premise) Therefore dolphins live in the sea (conclusion) </li></ul>
  15. 23. All basketballs are round. The Earth is round. Therefore, the Earth is a basketball.
  16. 24. Hypothetic-deductive method <ul><li>The formulation of an hypothesis (a tentative answer to a question) and the execution of experiments from which one may deduce a general answer to the hypothesis </li></ul>
  17. 25. Steps in scientific method <ul><li>Observation </li></ul><ul><li>Asking a critical question </li></ul><ul><li>Developing a hypothesis </li></ul><ul><li>Making a prediction that can be tested </li></ul><ul><li>Performing experiments to test the prediction </li></ul><ul><li>Collecting and analyzing data </li></ul><ul><li>Making a logical conclusion based on experimental results </li></ul>
  18. 27. Scientific method <ul><li>Observing and stating a research problem </li></ul><ul><li>Forming a hypothesis: gather information about the observed phenomenon and make a hypothesis </li></ul><ul><li>Testing the hypothesis </li></ul><ul><li>Experimentation </li></ul><ul><ul><li>Variable </li></ul></ul><ul><ul><li>Outcome </li></ul></ul><ul><ul><li>Control experiment </li></ul></ul><ul><ul><li>Recording and analysing results </li></ul></ul><ul><ul><li>Forming a conclusion </li></ul></ul>
  19. 29.
  20. 32. No amount of experimentation can ever prove me right; a single experiment can prove me wrong. Albert Einstein