Casal and Sturm present two different ways in which philosophy relates to science. Sturm begins by sketching “philosophical naturalism”, a view that tries to answer philosophical questions employing methods and data from the empirical sciences. He then analyses the ongoing debate between the “heuristics and biases” approach and the “bounded rationality” program in order to assess the potential of naturalizing rationality, and its limits.

1. RELATIONS BETWEEN PHILOSOPHY AND SCIENCE
FOR EXAMPLE: RATIONALITY
THOMAS STURM
HPS@BCN
Barcelona
History & Philosophy of Science
Research Group
R A T I O N A T U R A L
Naturalism and the Sciences of Rationality
Project FFI2016-79923-P
HPS@BCN
Barcelona
History & Philosophy of Science
Research Group
R A T I O N A T U R A L
Naturalism and the Sciences of Rationality
Project FFI2016-79923-P

2. § Disciplinary differentiation
§ Autonomy of philosophy/separation from science (after Kant)
§ Distinctive philosophical („a priori“) methods
§ Distinctive philosophical tasks/problems
§ Yet, philosophers often use science/collaborate with scientists
§ E.g. phil of mind & neurosciences; ethics & economics…
Intro: Philosophy and the Sciences
Krüger 1986; Friedman 1996

3. Naturalism
§ Began in epistemology, spread into other areas of philosophy
(ethics, metaphysics, semantics, phil of science…)
Ontological Naturalism: Reality consists only of natural objects,
their properties and relations – there are no unexplainable non-
or supernatural entities or powers.
Methodological Naturalism: Philosophical questions can/should
be answered by relying on the methods and results of the
sciences.
Quine 1969; Harman 1977; Goldman 1986; Kornblith 2002; Ladyman 2007;
De Caro & MacArthur 2004, 2010
Intro: Philosophy and the Sciences

4. Apriori Objections to Naturalism
■ Is-Ought fallacy (“Hume’s law”)
■ Circularity
■ Triviality
■ …
Such debates tend to far away from the sciences.
The proof of the pudding is in the eating.
What are the potentials, result, and limits of actual naturalistic uses
of science?
Intro: Philosophy and the Sciences

5. Rationality between Philosophy and Psychology:
Structure
1. The Heuristics and Biases Program in Psychology
2. Naturalism about Rationality and HB: A 1st Response
3. Objections by Psychologists to Heuristics and Biases
4. Naturalism and the Rationality Debate: A 2nd Response
5. Summary

6. 1.
Psychology of Rationality I:
Heuristics and Biases (HB)

7. ■ Are human judgments and decisions rational?
■ Instead of standard rules (logic, probability, rational choice),
people use heuristics (availability, representativeness, anchoring
& adjustment…) – leading to biases & fallacies.
Tversky & Kahneman 1974; Kahneman, Slovic & Tversky 1982; Gilovich, Griffin &
Kahneman 2002
Heuristics and Biases (HB):
Core Question & Main Hypothesis

8. Linda is 31 years old, single, outspoken and very bright. She
majored in philosophy. As a student, she was deeply concerned
with issues of discrimination and social justice, and also
participated in antinuclear demonstrations.
Which statement is more probable?
(T) Linda is a bank teller.
(T&F) Linda is a bank teller and active in the feminist
movement.
Norm: Conjunction rule - Prob (A) ³ Prob (A & B)
Results: About 85% of 142 subjects chose T&F and thus violated
the conjunction rule.
Explanation: Representativeness heuristic
Kahneman & Tversky 1983
Reasoning about Conjunctions

9. Assume two players, Mr Spock and Commander Kirk. Spock is given
100 Federation credits, but on the condition that he must somehow
split the sum with Kirk, with no option to communicate about this.
Kirk can accept or reject the offer. If Kirk rejects it, neither Spock
nor Kirk receive any money. What sum should Spock offer?
Norm: Maximize your own expected utility (Homo oeconomicus)
Results: Subjects often reject certain offers of such free money, e.g.
when the sum offered is below 30%. That violates the norm.
Explanation: E.g. desire to punish unfairness, reciprocal altruism
Güth, Schmittberger & Schwarze 1982
Ultimatum Game

10. ■ Violation of logical rules (Wason selection task)
■ Base rate fallacy (Harvard medical school problem…)
■ Overconfidence bias
■ Hindsight bias
■ Law of small numbers
■ Gambler’s fallacy
■ …
Wason 1966; Tversky & Kahneman 1974; Nisbett & Ross 1980;
Kahneman, Slovic & Tversky 1982; Gilovich, Griffin & Kahneman 2002
More biases & fallacies

11. “… bleak implications for human rationality” (Nisbett & Borgida,
1975)
“… irrationality rather than rationality is the norm.” (Wason,
1983)
“One might draw rather cynical conclusions ... Human reasoning
is fundamentally flawed” (Reisberg, 1997)
Bad news = good news:
The irrationality message

12. The Practical Significance of the Irrationality
Message
Irrationality leads to:
“…wars, economic busts,
technological accidents, pyramid
sales schemes,
telemarketing fraud, religious
fanaticism, psychic scams,
environmental degradation, broken
marriages, and savings and loan
scandals”.

13. 2.
Naturalism about Rationality and HB:
A First Response

14. A Naturalistic Absorption of HB
Stich (1985):
ü Empirical Methods & Results of HB
ü Irrationality message
ü Rejects philosophical attempts to
undermine the data and the
message: (i) Cohen’s defense of
impossibility of experimental proofs
of fundamental irrationality; (ii)
Dennett’s arguments from
intentionality
ü Reasoning ability isn’t distributed
equally; for education etc., we can
learn from psychology

15. 1. Constitutivity: What is rationality?
2. Normativity: How to justify norms of rationality?
3. Kantian Critique: What are the limits of rationality?
4. Philosophical Anthropology: Are humans the only rational
animals?
…
■ How far can such projects be pursued naturalistically?
Philosophical Questions about Rationality

16. Ontological Naturalism (ON): Reality consists only of natural objects,
their properties and relations – there are no unexplainable non- or
supernatural entities or powers.
Methodological Naturalism (MN): Philosophical questions
can/should be answered by relying on the methods and results of
the sciences.
ON-Rationality: Rationality is a natural faculty, with natural properties
and relations. There are no unexplainable non- or supernatural
aspects of rationality.
MN-Rationality: Questions concerning rationality can/should be
answered by relying on the methods and results of the sciences.
Rationality as the Naturalist Studies It

17. ON-Rationality:
■ HB program cannot help: It presupposes rather than discovers a
certain normative (sc. formal, maximizing) model of rationality.
■ Useless for ON-Rationality
■ Evolutionary psychology of reasoning?
MN-Rationality:
■ Which philosophical questions?
■ Stich follows the question: Are human beings rational? That’s
another topic.
■ Not clear how to connect to e.g. questions about the constitution
or about norms of rationality.
Missing One’s Own Goals

18. 3.
Objections (by Psychologists) to
Heuristics and Biases

19. 1. Are there no experimental artifacts?
2. Can people overcome “cognitive illusions”?
3. Are the norms used uncontroversial?
Cohen 1981; Gigerenzer 1991, 1996; Lopes 1991, 1992; Cosmides & Tooby 1996
Objections to HB

20. In the “Linda problem”, Kahneman & Tversky assume:
1. the terms ‘probable’ and ‘and’ are all that counts; & that ‘and’ is
understood as the logical ‘&’, and ‘probable’ conforms to
mathematical probability theory.
■ But ‘probable’ may mean other things too!
2. Forced alternative: Subjects must pick either “T” or “T&F”
■ Many people (20 to 50%) seem to infer that, for instance, “T”
means to exclude “F” (i.e., T = T&¬F).
Gigerenzer 1996; Sturm 2012
Are There No Experimental Artifacts?

21. Can People Overcome “Cognitive Illusions”?
Why “cognitive illusions?
Sturm 2014

22. Frequentist formulation of the task:
(Same description of Linda as before.)
There are 100 people who fit the description above. How
many of them are (a) bank tellers, (b) bank tellers and
active feminists?
Result: The conjunction fallacy dropped from about 85% to 20%
and even less
• Similar (and other) tools for e.g. base rate mistakes,
overconfidence bias…
Fiedler 1988; Hertwig & Gigerenzer 1999
Can People Overcome “Cognitive Illusions”?
The Linda Problem Reconsidered

23. ■ Linda Problem: Assumption of relevance of description of Linda
(Grice’s “maxim of relevance” of ordinary conversation)
■ Ultimatum Game: Egoistic utility maximization in single-shot
games; prudential reasoning in repeated games; or moral
rationality?
…
Ø Tendency to question the Irrationality message
Ø Alternative rational interpretations of subjects’ responses
Ø Open questions about what rationality is & what its norms are
Grice 1975; Hertwig & Gigerenzer 1999
Are the Norms Used Uncontroversial?

24. 4.
Naturalism and the Rationality Debate:
A Second Response

25. Peacemakers
Samuels, Stich & Bishop (2002):
§ “Rationality Wars” between HB
and evolutionary psychology
§ The dispute can be dissolved
§ Analysis of “core claims“ vs.
“rhetorical flourishings”

26. The Naturalistic Dissolution
E.g.
One core claim of HB
People’s intuitive judgments on many problems involving probability regularly
deviate from norms of rationality.
One rhetorical excess of HB
The only cognitive tools that are available to untutored people when dealing with
problems involving probability are normatively problematic heuristics.
One core claim of Evolutionary Psychology
There are many reasoning problems involving probability on which people’s intuitive
judgments do not deviate from norms of rationality.
One rhetorical excess of Evolutionary Psychology
Our probabilistic reasoning is subserved by “elegant machines” designed by natural
selection and, therefore, any concerns about systematic irrationality are unfounded.

27. ON-Rationality: Rationality is a natural faculty, with natural properties
and relations. There are no unexplainable non- or supernatural
aspects of rationality.
■ Samuels, Stich & Bishop still focus on the question: Are human
beings rational? How far?
■ What rationality is remains unaddressed
MN-Rationality: Questions concerning rationality can/should be
answered by relying on the methods and results of the sciences.
■ Still unclear e.g. what the justification of norms of reasoning is.
■ No discussion of “bounded rationality”
Missing One’s Own Goals

28. Bounded Rationality (BR)
Price for failures of HB-program according to Gigerenzer et al.:
Rationality is not valid independently of empirical facts about
human reasoning: it is „bounded“ by contents and contexts of
reasoning tasks.
Gigerenzer et al. 1999; Gigerenzer & Sturm, 2012

29. Fast and Frugal Heuristics (FFH)
Gigerenzer & Goldstein, 2011

30. 5.
Summary

31. 1. The debate is likely to continue. No convergence in sight.
2. Naturalistic hopes to answer questions about the constitution
or normativity of rationality by empirical methods are (at least)
premature.
3. Perhaps ‘(ir-)rationality’ isn’t a homogeneous concept.
4. The concept, and the ones connected to it (‘illusion’, ’bias’…)
must be reflected alongside ongoing psychological research.
5. So must be the norms of good reasoning.
6. No philosophical naturalism that ignores normative and
conceptual presuppositions of psychological research can be
taken seriously.
7. Collaboration between philosophy and psychology is instructive.
Consequences for the Philosophy-Science
Relation

32. Black, 1986
Reflect Your Intuitions: Ambiguities of rationality

33. Thanks.