Chapter 2: Science as a Way of Knowing: Critical Thinking About the Environment

Overview Understanding What Science is, and What it isn’t Understanding What Science is, and What it isn’t Observations, Facts, Inferences, and Hypotheses Observations, Facts, Inferences, and Hypotheses Measurements and Uncertainty Measurements and Uncertainty Misunderstandings about Science and Society Misunderstandings about Science and Society Environmental Questions and the Scientific Method Environmental Questions and the Scientific Method

Understanding What Science Is Scientific understanding of life and its environment is based on scientific method Scientific understanding of life and its environment is based on scientific method Science is a process Science is a process A way of knowing A way of knowing Results in conclusions, generalizations and sometimes laws Results in conclusions, generalizations and sometimes laws Allows us to explain a phenomenon and make predictions (based on knowledge at the present time) Allows us to explain a phenomenon and make predictions (based on knowledge at the present time)

Science as a way of knowing Continuous process Continuous process Sometimes a science undergoes a fundamental revolution in ideas Sometimes a science undergoes a fundamental revolution in ideas Science begins with observations Science begins with observations Example: Example: How many birds nest at Mono Lake? How many birds nest at Mono Lake? What food do they eat? What food do they eat? Deals only with statements that can be disproved Deals only with statements that can be disproved

Disprovability A statement can be said to be scientific if someone can state a method by which it could be disproved A statement can be said to be scientific if someone can state a method by which it could be disproved Many ways of looking at the world Many ways of looking at the world Distinction between scientific statement and nonscientific is not a value judgment Distinction between scientific statement and nonscientific is not a value judgment Simply a philosophical one Simply a philosophical one

Observations, Facts, Inferences, and Hypotheses Observations Observations Made by any of the five senses or instruments that measure beyond what we sense Made by any of the five senses or instruments that measure beyond what we sense Inference Inference Generalization that arises from a set of observations Generalization that arises from a set of observations Fact Fact observation about a particular thing agreed by all observation about a particular thing agreed by all

Hypothesis Type of statement used Type of statement used When scientists wish to test an inference When scientists wish to test an inference Can be disproved Can be disproved If a hypothesis has not been disproved If a hypothesis has not been disproved Is still not proven true Is still not proven true Only found to be probably true Only found to be probably true

Controlling Variables A valid scientific experiment keeps all variables constant, except the independent and dependent variables A valid scientific experiment keeps all variables constant, except the independent and dependent variables Controlled experiment Controlled experiment An exact duplicate of an experiment is compared back to a standard or control An exact duplicate of an experiment is compared back to a standard or control One variable is altered (independent variable) One variable is altered (independent variable) This may cause a change in another variable in the experiment (dependent variable) This may cause a change in another variable in the experiment (dependent variable)

Variables Dependent variable Dependent variable rate of photosynthesis rate of photosynthesis Independent variable Independent variable amount of light amount of light Manipulated variable Manipulated variable Ind. variable because can be changed Ind. variable because can be changed Responding variable Responding variable Dependent variable because it responds to change Dependent variable because it responds to change

Data Quantitative - numerical Quantitative - numerical Ex: diameter of a tree trunk Ex: diameter of a tree trunk Qualitative - non-numerical Qualitative - non-numerical Ex: species of tree Ex: species of tree

Inductive v. Deductive Reasoning Scientific Reasoning combines both deductive and inductive reasoning Scientific Reasoning combines both deductive and inductive reasoning Deductive reasoning Deductive reasoning Involves reasoning from initial definitions and assumptions Involves reasoning from initial definitions and assumptions Keep in mind, science requires not only logical reasoning, but correct premises Keep in mind, science requires not only logical reasoning, but correct premises

Deductive reasoning Premise: a straight line is the shortest distance between two points Premise: a straight line is the shortest distance between two points Premise: The line from A to B is the shortest distance between points A and B Premise: The line from A to B is the shortest distance between points A and B Conclusion: Therefore, the line from A to B is a straight line Conclusion: Therefore, the line from A to B is a straight line Proof using deductive reasoning does not require that the premises be true, only that the reasoning foolproof Proof using deductive reasoning does not require that the premises be true, only that the reasoning foolproof

Deductive reasoning Premise: Humans are the only tool making organisms Premise: Humans are the only tool making organisms Premise: the woodpecker finch uses tools Premise: the woodpecker finch uses tools Conclusion: Therefore, the woodpecker finch is a human being! Conclusion: Therefore, the woodpecker finch is a human being!

Inductive v. Deductive reasoning Inductive Reasoning Inductive Reasoning Generalizations based on a number of observations Generalizations based on a number of observations Example Example Breeding male grebes have golden feathers Breeding male grebes have golden feathers This is only true until we observe a breeding male grebe that does not have golden feathers This is only true until we observe a breeding male grebe that does not have golden feathers Proof of inductive reasoning is stated in terms of probability of occurance Proof of inductive reasoning is stated in terms of probability of occurance

Measurements and Uncertainty When we add numbers to our analysis When we add numbers to our analysis Obtain another dimension of understanding Obtain another dimension of understanding Visualize relationships Visualize relationships Make predictions Make predictions Analyze strength of relationships Analyze strength of relationships

Models and Theory Model Model A deliberately simplified construct of nature A deliberately simplified construct of nature Many types of models Many types of models Physical working model Physical working model Pictorial model Pictorial model Set of mathematical equations Set of mathematical equations Computer model Computer model

Measurements and Uncertainty People generally put more faith into the accuracy of measurements than do scientists People generally put more faith into the accuracy of measurements than do scientists Measurements are useless unless accompanied by an estimate of their uncertainty Measurements are useless unless accompanied by an estimate of their uncertainty Experimental error Experimental error

Historical Evidence- Alternative to Direct Experimentation Frequency of fires in the BWCA of MN Frequency of fires in the BWCA of MN Three kinds of data used Three kinds of data used Written records Written records Tree-ring records Tree-ring records Buried records (fossil and pre-fossil org deposits) Buried records (fossil and pre-fossil org deposits) Fire scars could be seen in record Fire scars could be seen in record

Historical Evidence By examining cross sections By examining cross sections Possible to determine the date of each fire Possible to determine the date of each fire Number of years between fires Number of years between fires Heinselman determined it burned once per century Heinselman determined it burned once per century Fires shown to be integral part of forest ecology Fires shown to be integral part of forest ecology

Historical Evidence Historical info meets the primary requirement of scientific method Historical info meets the primary requirement of scientific method Ability to disprove a statement Ability to disprove a statement Major source of data that can be used to test hypotheses in ecology Major source of data that can be used to test hypotheses in ecology

Accuracy and Precision Accuracy Accuracy What we know What we know Extent to which a measurement agrees with the accepted value Extent to which a measurement agrees with the accepted value Precision Precision How well we measure How well we measure The degree of exactness with which the quantity was measured The degree of exactness with which the quantity was measured

Process of Making Decisions - Similar to Scientific Method 1. Formulate a clear statement of the issue to be decided 2. Gather the scientific information related to the issue 3. List all alternative courses of action 4. Predict the positive and negative consequences of each course of action and the probability that each consequence will occur. 5. Weigh the alternatives and choose the best solution.

Misunderstandings about Science Scientific theory - grand scheme that relates and explains many observations and is supported by a great deal of evidence Scientific theory - grand scheme that relates and explains many observations and is supported by a great deal of evidence In everyday usage theory may mean a guess, a hypothesis, a prediction, a notion, a belief In everyday usage theory may mean a guess, a hypothesis, a prediction, a notion, a belief

Science and Technology Science is a search for understanding Science is a search for understanding Technology is the application of scientific knowledge that benefits humans Technology is the application of scientific knowledge that benefits humans The two are intertwined The two are intertwined In our daily lives most of us do not encounter science but the products of science In our daily lives most of us do not encounter science but the products of science

Misunderstandings about Science Myth of objectivity or value free science Myth of objectivity or value free science Pseudoscientific Pseudoscientific Untestable, lack empirical evidence or based on faulty reasoning Untestable, lack empirical evidence or based on faulty reasoning Frontier science Frontier science Ideas that may move into realm or science or pseudoscience Ideas that may move into realm or science or pseudoscience

Environmental Questions and the Scientific Method Environmental sciences deal with especially complex systems. Environmental sciences deal with especially complex systems. Not as neat as the scientific method Not as neat as the scientific method Different approach has been used in environmental sciences Different approach has been used in environmental sciences Example: California Condor Example: California Condor