What do you expect from Science?What do you expect from Science? Science is a Science is a processprocess, not a thing., not a thing. Science is a paradigm based on Science is a paradigm based on understandingunderstanding nature (rather than nature (rather than passively observing it, passing passively observing it, passing judgment on it, or anthropomorphizing judgment on it, or anthropomorphizing it).it).

Understanding nature involves Understanding nature involves reasoningreasoning..

Thinking Critically about Thinking Critically about ScienceScience

It doesn’t deal with It doesn’t deal with untestableuntestable concepts (e.g., concepts (e.g., absolutes such as good and evil) absolutes such as good and evil) They can be They can be observed (felt), but not measured (well, that’s observed (felt), but not measured (well, that’s debatable…)debatable…)

Subjective ways of looking at the world Subjective ways of looking at the world (morals, religion, aesthetics) are not scientific (morals, religion, aesthetics) are not scientific concepts, they are absolutes (truths?): they concepts, they are absolutes (truths?): they are based on faith, beliefs, cultural and are based on faith, beliefs, cultural and personal personal valuesvalues

What Science Isn’t

scientific knowledge is tentative (subject to scientific knowledge is tentative (subject to change)change)

empirically-based (based on and/or derived empirically-based (based on and/or derived from observations of the natural world)from observations of the natural world)

subjective (theory-laden)subjective (theory-laden) necessarily involves human inference, necessarily involves human inference,

imagination, and creativity (involves the imagination, and creativity (involves the invention of explanations)invention of explanations)

and is socially and culturally embeddedand is socially and culturally embedded

What Science (probably) is…

Assumptions of ScienceAssumptions of ScienceFor Science to work, it has to follow certain rules and guidelines For Science to work, it has to follow certain rules and guidelines which which are notare not questionedquestioned:: Patterns in the natural world can be understood by careful Patterns in the natural world can be understood by careful

observation and analysis.observation and analysis. the patterns should be repeatable in space and time (they the patterns should be repeatable in space and time (they

should apply: i.e. Physics!).should apply: i.e. Physics!). Science uses Reasoning (makes specific observations and Science uses Reasoning (makes specific observations and

arrives at general conceptualizations arrives at general conceptualizations hypotheseshypotheses).). These generalizations must be These generalizations must be testabletestable for falsehood for falsehood

Yes you’re good to go Yes you’re good to go No go back to the drawing table…No go back to the drawing table…

State of ScienceState of Scienceo New observations can disprove theories or fail to New observations can disprove theories or fail to

do so (dethronement is our lot) Dynamic do so (dethronement is our lot) Dynamic feedback and self-correctionfeedback and self-correction

o However, observations and scientific However, observations and scientific interpretations of these can never provide truth interpretations of these can never provide truth (no absolute proof of the truth of theories: (no absolute proof of the truth of theories: Changing views and concepts!) Science models Changing views and concepts!) Science models do do notnot necessarily represent reality! necessarily represent reality!

o Science is not more procedural than creative!Science is not more procedural than creative!

Science andScience and ObjectivityObjectivity

MythMyth:: Scientists are NOT Scientists are NOT influenced by the social influenced by the social environment (REM: Spock??)environment (REM: Spock??)

more realistic approach: more realistic approach: recognize that we are all recognize that we are all influenced,influenced, estimate its effectestimate its effect

doesn’t mean fuzzy thinking doesn’t mean fuzzy thinking is acceptableis acceptable, , one must still one must still think criticallythink critically

What are we really comparing?What are we really comparing?

DeductionDeduction vs. vs. InductionInduction DeductionDeduction goes from general statements goes from general statements

(which may or may not be correct) to account (which may or may not be correct) to account for specific experimental results, (does not for specific experimental results, (does not require the premises to be true): Swans require the premises to be true): Swans

InductionInduction (inductive generalizations) goes (inductive generalizations) goes from specific observations to general from specific observations to general statements which can be tested and are statements which can be tested and are accepted as correct until proven wrong.accepted as correct until proven wrong.

Deductive vs. Inductive Deductive vs. Inductive ProofsProofs:: an examplean example

problemproblem: Deductive reasoning does not require that : Deductive reasoning does not require that the initial premises be correct, the final statement is the initial premises be correct, the final statement is always truealways true

• humans are the only toolmakers

• Chimps use tools Chimps are humans!

• can lead to false conclusions:

error: humans aren’t the only toolmakers!error: humans aren’t the only toolmakers! RephrasingRephrasing: : If If humans are the only toolmakers, humans are the only toolmakers,

and and If If Chimps use tools, Chimps use tools, thereforetherefore Chimps are Chimps are humans…humans…

inductive thinking requires that all premises be true (tested by science)

this leads to the concepts of measurement error, uncertainty, and probability

Every measurement is Every measurement is only and approximation! only and approximation! (measurement uncertainties are inevitable)(measurement uncertainties are inevitable)

Any measurement is meaningless unless it is presented with Any measurement is meaningless unless it is presented with an estimate of its uncertainty (variability)an estimate of its uncertainty (variability)

Scientific Proofs Scientific Proofs Measurement Error!Measurement Error!

0.04

0.08

0.12

0.16

0.2

0 1 2 3 4 5 6 7 8 9

Corg (mg)

S/V

S/V (Gluc.)

c

Scientific observations are always uncertain (not Scientific observations are always uncertain (not algorithmic!)algorithmic!)

RealityReality: at some level, the original observation is : at some level, the original observation is always uncertain (the fewer the observation, the always uncertain (the fewer the observation, the higher the uncertainty).higher the uncertainty).

““Demontrating” something by inductive reasoning Demontrating” something by inductive reasoning only means that it has a only means that it has a high degreehigh degree of happening of happening again: again: probabilityprobability (e.g., sunrise/sunset)(e.g., sunrise/sunset)

Unfortunately, we may interpret these conclusions Unfortunately, we may interpret these conclusions as truth (!!!) - And we teach science that way!as truth (!!!) - And we teach science that way!

Scientific Knowledge is Inherently Scientific Knowledge is Inherently uncertain: uncertain: ProbabilityProbability

Probability: Probability: uncertaintyuncertainty

Scientific precision is Scientific precision is based on the based on the degree degree of uncertaintyof uncertainty in the in the original observation.original observation.

A conclusion is thus A conclusion is thus fatally flawed at some fatally flawed at some level.level.

www.weather.com

Accuracy vs. Accuracy vs. PrecisionPrecision

AccuracyAccuracy: : the degree to which a measurement the degree to which a measurement agrees with an accepted valueagrees with an accepted value

Accepted valueAccepted value??? Depends on consensus of ??? Depends on consensus of measurement takers (example: water freezes at measurement takers (example: water freezes at 00ooC)C)

PrecisionPrecision: : the degree of exactness to which the the degree of exactness to which the measurement is made (e.g., “that’s hot” vs. measurement is made (e.g., “that’s hot” vs. 100.000100.000ooC C how big is the error bar how big is the error bar relativerelative to the to the value)value)

QuestionQuestion: If you measure the temperature of boiling : If you measure the temperature of boiling water and find it to be 98.750water and find it to be 98.750ooC, are you more or C, are you more or less precise than 100less precise than 100ooC? More accurate???C? More accurate???

AnswerAnswer: you are more : you are more preciseprecise, but less , but less accurateaccurate

Science andScience and Objectivity Objectivity MythMyth:: Method of Science is Method of Science is directional (procedural)directional (procedural)!! Doesn’t leave any room for Doesn’t leave any room for serendipityserendipity, , creativitycreativity, and , and

inspirationinspiration..

Science andScience and Objectivity Objectivity MythMyth:: Method of Science is Method of Science is directionaldirectional!! Doesn’t leave any room for Doesn’t leave any room for serendipityserendipity, , creativitycreativity, and , and

inspirationinspiration..

•However, you must maintain critical thinking about observations

Env. Sciences are basically Env. Sciences are basically human!human!

The overall “picture” is more than just the sum of its The overall “picture” is more than just the sum of its componentscomponents

Env. Science is intrinsically non-reductionist by nature! Env. Science is intrinsically non-reductionist by nature! The production of a common language (inclusive rather than The production of a common language (inclusive rather than

reductionist) is primordial to the communication of a reductionist) is primordial to the communication of a mutidisciplinary base of knowledge!mutidisciplinary base of knowledge!

Env. Sciences thus need horizontality and verticality!Env. Sciences thus need horizontality and verticality! Decision makers (in Env. Sciences) need the language and Decision makers (in Env. Sciences) need the language and

the basic understanding to create a dialogue between the basic understanding to create a dialogue between horizontal and vertical seekershorizontal and vertical seekers

Language of Env. SciencesLanguage of Env. Sciences

The difficulty of Env. Sciences is to manage a partial The difficulty of Env. Sciences is to manage a partial knowledge of complex systems! knowledge of complex systems!

What is complicated What is complicated vsvs. complex?. complex? We thus only obtain partial images of complex systems (we We thus only obtain partial images of complex systems (we

try to extrapolate from incomplete knowledge).try to extrapolate from incomplete knowledge). Uncertainty leads to “precautionary principle” Uncertainty leads to “precautionary principle” Absence of Absence of

certainty should not retard the adoption of efficient certainty should not retard the adoption of efficient measures to prevent large-scale consequencesmeasures to prevent large-scale consequences

Climate Change – Toxic Elements (As, PCB)Climate Change – Toxic Elements (As, PCB)

Language of Env. SciencesLanguage of Env. Sciences