Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and...

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Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San Diego

Transcript of Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and...

Page 1: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Decision-making under uncertainty: Is there any other

kind?

Naomi OreskesHistory Department andScience Studies Program

University of California, San Diego

Page 2: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

““Decision-making under uncertainty” Decision-making under uncertainty” implies the existence of an alternativeimplies the existence of an alternative

Presumably: decision-making under conditions of certainty

Page 3: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

No such thing

Statistician George Chacko (1991) defines decision-making as “the

commitment of resources today for results tomorrow.”

Page 4: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Because decisions involve Because decisions involve expectations about the future, expectations about the future,

they always involve uncertaintythey always involve uncertainty

Page 5: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

If people talk about “certainty” they can only be referring to

certainty about what they want the outcome to be (desires)

Page 6: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Why would anyone even imagine certainty is possible?

• Decision-making involves premises (assumptions, beliefs, conditions)

• Logic tells us that if premises of a conditional statement are correct, then outcome is known (predictable).

• Common assumption: the premises are correct. (Least examined aspect)

Page 7: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

In environmental decision-making, the premises typically include

“underlying scientific information”

Examples?

CO2 is a greenhouse gas

Lead is a neurotoxin

Marine biodiversity is declining

Page 8: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

We take these things to be true, and I’ve chosen examples that I

think are true.

But experience proves that widely accepted premises may

turn out to be incorrect

Page 9: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Premises can always be disputed.Premises can always be disputed.• Marine biodiversity is declining

Ransom Myers and Boris Worm, 2003. "Rapid worldwide depletion of predatory fish communities." Nature 423: 280-283.

• Is it really? Or is it just a handful of heavily hunted fish and mammals species?

• Response: Sloan Foundation Census of Marine Biodiversity. More information to test premise.

Page 10: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Certainty is a false idolCertainty is a false idol

Why would anyone imagine that scientific knowledge could be certain?

Page 11: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Erroneous and refuted conception of science: Positivism

Page 12: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Sea of “positivist expectation”

Certain knowledge based on

1. Observable foundations

2. Verifiable implications

Page 13: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

No need to be cruel…

Positivist aspirations were laudable enough: Science as alternative to

superstition, clericalism, confusion.

Page 14: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Positivists asked important questions

• What aspects of scientific investigation account for the reliability of the knowledge produced?

• Can those elements be adopted by others wishing to increase the robustness of their own investigations?

• Can these elements be used as a criterion for judging information?

Page 15: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

But the vision failed• Historically: it fails to account for major

conceptual revisions in science.

• Philosophically: it fails to account for the diversity of scientific methods and the flexible interplay between theory and observation.

• Sociologically: it fails to account for the social dimensions of scientific proof and persuasion. Verification of knowledge is a social process.

Page 16: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Alternative? Alternative? Science as an intellectual Science as an intellectual and social consensus of and social consensus of

affiliated expertsaffiliated experts

Page 17: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Scientific consensus achieved by

1. Consilience of empirical evidence, achieved by tested methodologies.

2. Coherence between evidential frameworks and theoretical understandings

3. “Theoretical integrity” (relation to existing beliefs and commitments)

4. Social organization for establishing and declaring agreement on all of the above.

Page 18: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Does this process eliminate uncertainty?

Of course not.

Page 19: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

So how do we judge consensus?So how do we judge consensus?

How should we response to the presence of vocal dissenters, and

imperfect data?

Page 20: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Need to reject a second false idol: Need to reject a second false idol:

“The Kuhnian expectation”“The Kuhnian expectation”• Kuhn’s famous paradigm concept accounted

for the social dimensions of scientific consensus and the historical reality of conceptual change.

• Left us with an incorrect impression of “normal science”: dissent- & anomaly-free

Page 21: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Science as dissent-free

In Structure (1962) Kuhn wrote:“What is surprising, and perhaps also

unique in…the fields we call science, is that…initial divergences…disappear to

a very considerable extent, and then

apparently once and for all.”

What characterizes--even defines--science is unanimity

Page 22: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Science as anomaly-free

• Kuhn characterized normal science as (essentially) anomaly-free, with emergence of an anomaly as the beginning of crisis.

• Most “problems” are viewed as “puzzles.” When puzzle changes to an “anomaly”--> crisis --> revolution.

Page 23: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

““When…an anomaly comes to When…an anomaly comes to seem more than just another seem more than just another puzzle of normal science, the puzzle of normal science, the

transition to crisis…has begun.”transition to crisis…has begun.”

Page 24: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Left impression that normal science involves few if any meaningful uncertainties.

Just filling in details.

Page 25: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

A very mistaken view, as erroneous and damaging as the

positivist view

Generates impossible expectations.

Gives fodder for exploitation of dissent.

Page 26: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Alternative? Alternative? Living with uncertaintyLiving with uncertainty

Page 27: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

If uncertainty, anomalies, and dissent are normal science, how can we learn to live with them?

I. A “reasonable expectations” model

II. Taxonomy of uncertainties to help to identify useful courses of action.

Page 28: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

A “reasonable expectations” modelA “reasonable expectations” model

• Consensus unanimity

• There are always dissenters.

– Better: “outliers”

• There are always anomalies

• Anomalies and outliers can (and probably will) be exploited.

Page 29: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

A taxonomy of uncertaintyA taxonomy of uncertainty(preliminary)(preliminary)

I. Science not generally accepted--active scientific debate by scientists

II. Science mostly accepted by scientists, perhaps some outliers.

III. Science contested by parties outside the scientific community

Page 30: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

Appropriate responses depend on the situation

Page 31: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

I. Area of active scientific debate

Response: More research.

While no guarantee, increased knowledge base has potential to increase technical consensus.

Page 32: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

II. Science mostly accepted by scientists, with some outliers

More scientific research is unlikely to decrease uncertainty.

In fact, it may increase it.

More information less uncertainty

Existing consensus can be destabilized.

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III. Science contested by parties outside the scientific community

• The issues at stake are almost certainly not technical (moral, political, religious, aesthetic).

• More technical research will not resolve disputes.

• Inclusionary processes essential.

Page 34: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

More science is unlikely to help More science is unlikely to help us make our most important us make our most important

decisionsdecisions

Page 35: Decision-making under uncertainty: Is there any other kind? Naomi Oreskes History Department and Science Studies Program University of California, San.

References

• George Chacko, 1991, Decision-making under uncertainty: An Applied Statistics Approach, New York: Praeger1991, quote on p. 5

• Kuhn, T. S., 1962. The Structure of Scientific Revolutions, University of Chicago Press, quote on p. 17, 82.