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,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Why Believe a Computer?The Role of Quantitative Models in Science,Naomi Oreskes,Powerpoint by:,Fernanda Rossi,Jessica Matthews,Why Believe a Computer?The,1,Overview,Models are used to:,Organize data,Synthesize information,Make predictions,Models never fully represent so therefore make uncertain predictions,Added complexity in model decreases certainty of predictions,Short-time frame model vs.long-range deterministic model,OverviewModels are used to:,2,Models as a Science?,“Testing is the heart of science.Although there is no foolproof way to define science,testability is the most commonly cited demarcation criterion between scientific theories and other forms of human explanatory effort.”,A single test is rarely,if ever,sufficient to convince anyone of anything,Models as a Science?“Testing i,3,The Role of Quantitative Models in Science,Purpose of model is to gain understanding of natural world,Scientists have sought understanding to:,Advance utilization of earths resources,Foster industrialization,Prevent or treat diseases,Generate origins stories,Reflect on worlds creator,Satisfy human curiosity,The Role of Quantitative Model,4,Until 20,th,century,the word“model”in science referred to physical model,Now“model”refers to a computer model,A numerical simulation of a highly parameterized complex system,Quantitative models in ecosystem science have 3 functions:,Synthesis and integration of data,Guiding observation and experiment,Predicting or forecasting the future,Until 20th century,the word“,5,generated predictions are used as a basis for public policy,government regulators and agencies may be required by law to establish their trustworthiness(,How is this problematic?),Demand for“verification”or“validation”,Claims about model verification are now routinely found in published scientific literature.Are these claims legitimate?Can a computer be proved true or false?How can we tell when to believe a computer?,generated predictions are used,6,The Problem of Verification,There may be several possible configurations of nature that could produce a given set of observed results,Therefore,any empirical data we collect in support of a theory may also be consistent with alternative explanations,For this reason,many scientists except the view that theories can be proved false but not true(falsified but not verified),The Problem of VerificationThe,7,Purpose of essay is therefore to challenge the utility of models for prediction,Quantitative model output has been used in issues such as global climate change and radioactive waste disposal,But it is open to question whether models generate reliable information about the future,Should we create new policies based on the prediction of models?,Purpose of essay is therefore,8,Naomis Opinion,The predictions models offer to us do not aid in basic scientific understanding,Our use of them does not make them important,More complex models tend to be less accurate,Naomis OpinionThe prediction,9,Example of Assumptions we Make:,Stellar parallax in the establishment of the heliocentric model of planetary motion by Nicolaus Copernicus,Flaws present in instruments we use,Example of Assumptions we Make,10,Another Example:,Earth was thought to be billions of years old based on the concept of uniformitarianism the assumption that presently observable geological processes are representative of Earths history in general,Then,Lord Kelvin calculated the time required for a molten body the size of earth to cool to its present temperature was at most 98 million years,declaring the entire science of geology invalid,This dismissed Charles Darwins theory of natural selection and for several decades evolutionists were in nearly full retreat,THEN,radioactivity was discoveredproving Kelvin wrong.,Another Example:Earth was thou,11,In hindsight,it is easy to see where others have gone wrong:Astronomers thought their instruments were better than they were;Kelvin thought his knowledge more complete than it was.It is harder to see the flaws in our own reasoning.(If we
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