1. Science as a way of knowing the world
John S. Wilkins, Philosophy, University of Queensland
2. The scientiļ¬c method
ā¢ Who can summarise the scientiļ¬c method?
ā¢ Who is right? Answer: Probably everyone
ā¢ There is no single algorithm for the scientiļ¬c method. Itās not a recipe for
success
ā¢ But there are several shared features of all acts of science
ā¢ There are also several shared mistakes scientists make
ā¢ Today I want to discuss some of these.
3. The scientiļ¬c method is a dance
ā¢ Just as thereās not much that all dances share apart from a dance ļ¬oor,
thereās not much that all sciences share either
ā¢ But there are some common features:
ā¢ Theories
ā¢ Models
ā¢ Data
ā¢ Classiļ¬cations
4. The scientiļ¬c method is a dance
ā¢ Just as thereās not much that all dances share apart from a dance ļ¬oor,
thereās not much that all sciences share either
ā¢ But there are some common features:
ā¢ Theories
ā¢ Models
ā¢ Data
ā¢ Classiļ¬cations
23. Making models
ā¢ Theories are composed of models, together with linking (ābridgingā) rules that
relate them, and āinterpretationsā, or ways to assign empirical data to the
variables of the theory
ā¢ In an example, consider the theory of global warming: There are many models
(of heat sink and dissipation of oceans, of carbon dioxide absorption, etc.),
which inter-relate, but all have different equations governing the model, and
different sets of variables
ā¢ A model is basically a set of inter-related equations. They are based on prior
knowledge of how things work, together with observations of the conditions
of the thing[s] under study
ā¢ How do we know what prior knowledge applies in this case?
24. Theories and models
ā¢ There are several kinds of theory and several kinds of model. Some theories
apply in every case (e.g., laws of physics). Some apply only in limited cases (a
theory of the origins of the Civil War in England).
ā¢ What kinds of theory and models apply in ecology and conservation?
ā¢ Global theories (island biogeography?)
ā¢ Restricted theories (trophic relations in, say, tropical savannah biomes)
ā¢ Local models (a model of what will happen in a certain system)
25. What worries me about conservation biology
ā¢ I have seen a lot of discussion about the right methods to develop
conservation plans, from Bayesian models to decision theoretic accounts
based on expected payoffs and values
ā¢ I have heard of a lot of conservation plans that deal with individual based
models or āagentā modelling (the idea is to model the ecosystem or area
without a general rule, but use dynamics of individual organisms to predict
how things will develop in complex cases) ā what seems to be lacking with
these is follow-up.
ā¢ How successful were they?
ā¢ What general problems were encountered?
ā¢ How can the models be improved?
ā¢ Without knowledge of rules of success, this is merely a matter of being seen
to do something
26. Mistakes that scientists make with theories and
models
ā¢ Suppose we have a theory (of being called in the
bath); we have to test it and revise it
ā¢ We need to ensure that the theory is not mistaken
for the thing (this is called reiļ¬cation or
āthingifyingā) ā the map is not the territory
ā¢ Often arguments between scientists overlook this
distinction: theories are in heads. The world is not
(except for the bits of the world that are heads)
ā¢ So the objects of the theory can be wrongly
ascribed (for example, genes)
27. Mistakes that scientists make with theories and
models
ā¢ Models are simpliļ¬cations ā often over simpliļ¬cations
ā¢ So if a model predicts X, it need not be that X will
follow
ā¢ If a model is not robust, slight differences in the
conditions will cause great differences in outcomes
ā¢ If there are things happening the model doesnāt
cover, predictions can be wildly wrong
ā¢ If several models are not independent (i.e., they
share assumptions, equations, methods, data sets)
then they may not be additive in their weight
ā¢ Theories can force models that back up those same
theories; be careful of circularity
28. Summary
ā¢ Science is like an open dance ļ¬oor - ļ¬ll in the empty spaces! [In more formal
language - the aspects of the scientiļ¬c process that are lacking in your ļ¬eld
need to be done]
ā¢ Theories are not useful in themselves unless they are tested and reļ¬ned
ā¢ And neither are models, methods, protocols, procedures or practices
ā¢ Donāt confuse whatās in the theory (in yours and othersā heads) with whatās in
the world
ā¢ And ļ¬nally: all of this is subject to practical need
29. Resources
ā¢ Figures and argument at Backreaction, a blog by two physicists
ā¢ Science as a Way of Knowing, by John Moore
ā¢ Ecological Orbits: How Planets Move and Populations Grow, by Mark Colyvan
and Lev Ginsburg
ā¢ Wikipedia articles: Epistemology, Science, Scientiļ¬c Method, Models of
Scientiļ¬c Enquiry
ā¢ Stanford Encyclopedia of Philosophy articles: Epistemology, Scientiļ¬c
Method, Models in science
