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2015 Lectures

Presented by , UC President's Professor of Philosophy (emerita), University of California, San Diego)

Abstracts

Lecture 1: Where do moral values come from?

Abstract: Self-caring neural circuitry embodies self-preservation values, and these are values in the most elemental sense. Whence caring for others? The compelling line of evidence from neuroendocrinology suggests that in mammals and possibly birds, caring for others is an adaptation of brainstem-limbic circuitry whereby what counts as "me" extends to include offspring -- "me and mine". Oxytocin is at the hub of the intricate network adaptations. In some species, strong caring for the well-being of others may extend also to include kin or mates or friends or even strangers, as the circle widens. Two additional interdependent evolutionary changes are crucial for mammalian sociality/morality: (1) modifications to the reptilian pain system that, when elaborated, yield the capacity to evaluate and predict what others will feel, know, and do, and (2) learning, strongly involving imitation, linked to social pain and social pleasure that regulates the acquisition of the clan's social practices and the emergence of a conscience tuned to these practices. Social problem-solving, including policy-making, is probably an instance of problem-solving more generally, and draws upon the capacity, prodigious in humans, to envision consequences of a planned action. In humans, it also draws upon the capacity for improving upon current practices and technologies. Unlike other mammals, humans have developed highly complex language, and highly complex cultures. This means that our sociality, and consequently ours systems of ethical values, have become correspondingly complex.

Lecture 2: Free will & self-control

Abstract: Free will is a topic of practical significance, especially in the context of the law but also in the socialization of children. The idea that free will is an illusion, recently bruited by trendy writers, is rooted on a rigid 17th century Cartesian theory according to which no decision is truly free unless it occurs in a causal vacuum. Because brains make decisions and decisions emerge from causal interactions, free will allegedly gets no purchase. Rather alarmingly, this view may inspire a call to radically revise the criminal law. To update our ideas of free will, it is useful to shift debate away from the puzzling metaphysics of causal vacuums to the neurobiology of self-control. Understanding is aided by research that maps the neural mechanisms supporting self-controlled behavior, in both animals and humans. Noteworthy also are data on decision-making that indicate a role for counterfactual learning signals, observing that this function can be impaired by, for example, nicotine. Not surprisingly, genetics play a significant role in the base-line capacities related to self-control, as is suggested by the stable patterns of self-controlled behavior over a 60 year period. Although the criminal law is unlikely to be revised to provide a new kind of excuse to reflect genetic differences in self-control and the reward system, such data may be modestly relevant to discretionary sentencing judgments. The more profound importance of emerging data on self-control will concern interventions relevant to addictions and compulsions.

2013 Lectures

Presented in March 2013 by Per Martin-Löf (Emeritus Professor of Logic, University of Stockholm and Member, Royal Swedish Academy of Sciences and Academia Europaea).

Invariance Under Isomorphism and Definability

Abstract

In a paper from 1934-35, printed in 1936, Lindenbaum and Tarski proved that every object which is definable in simple type theory is invariant under all automorphisms of the individual domain, that is, under all isomorphisms between the individual domain and itself. Thirty years later, in a lecture given at Buffalo in 1966, Tarski proposed to use isomorphism invariance as a criterion for distinguishing between logical and non-logical notions, a distinction the arbitrary character of which he was dissatisfied with in his well-known paper on the concept of logical consequence from 1936.

What happens if we replace classical simple type theory, which is impredicative, and which Lindenbaum and Tarski took to be extensional, by intuitionistic type theory, which differs from classical simple type theory, not only by being intuitionistic, or constructive, but also by being predicative and intensional? At first sight, there appears to be an insuperable obstacle to proving an analogue of the Lindenbaum-Tarski theorem for intuitionistic type theory, namely the presence in it of specific individuals, like zero, which is an element of the set of natural numbers, and zero and one, interpreted as the two elements of the two-element set. Clearly, they are not invariant under arbitrary isomorphisms. There is, however, a way out of this impasse, namely to understand by an isomorphism between two sets no more than a relation between the two sets, and to define a function to be isomorphism invariant if it is extensional, that is, if it yields isomorphic values when it is applied to isomorphic arguments. On this new interpretation of the concepts involved, it does become possible to demonstrate the following analogue of the Lindenbaum-Tarski theorem:

Every object that can be defined in intuitionistic type theory is invariant under isomorphism.

The demonstration takes the form of a model construction as a result of which each definable object gets accompanied by a proof that it is isomorphism invariant.

Lecture I will deal with the forms of judgment of intuitionistic type theory and the categories that correspond to them, making clear what elements of these forms are allowed to be reinterpreted in a non-standard model as opposed to those whose meaning has to remain untouched by any reinterpretation. Lectures II and III will be devoted to the details of the model construction which establishes the stated analogue of the Lindenbaum-Tarski theorem.

References:

A. Lindenbaum and A. Tarski, Über die Beschränktheit der Ausdrucksmittel deduktiver Theorien, Ergebnisse eines mathematischen Kolloquiums, Heft 7 (für das Jahr 1934-35, erschienen 1936), pp.15-22.
A. Tarski, Über den Begriff der logischen Folgerung, Actes du Congrès International de Philosophie Scientifique, fasc. 7, Actualités Scientifiques et Industrielles, vol. 394 (1936), pp. 1-11.
A. Tarski, What are logical notions?, History and Philosophy of Logic, vol. 7 (1986), pp. 143-154.

Related Paper:
Essay on the Philosophical Work of Per Martin-Löf

2010 Lectures

Presented in October 2010 by Brian Skyrms

University of California, Irvine

Naturalizing the Social Contract, October 19
Signals: Evolution, Learning and Information, October 21
On Dynamics and Signaling, October 22

2004 Lectures

Presented in October 2004 by Terrence J. Sejnowski (Salk Institute for Biological Studies)

2002 Lectures

Presented in February 2002 by Bas van Fraassen (Princeton University)

2000 Lectures

Presented in March 2000 by Stuart Kauffman (Santa Fe Institute)

1997 Lectures

Presented in November 1997 by Parick Suppes (Stanford University)