The neurobiological nature of free will

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Transcript of The neurobiological nature of free will

Björn Brembs

http://brembs.net

Universität Regensburg

“If we choose to remain at rest, we may; if we choose to move, we also may”

David Hume (1711-1776)

“We could often have done otherwise than we in fact did”

Searle 1984

“I could have done otherwise”

Taylor & Dennett 2002

Hans Flohr

Dr Lisa Jones University of St Andrews

1. Determinism rules out freedom

2. Randomness doesn‘t make us free either

Freedom cannot exist / is a useless concept

Double-Incompatibilists:

What is behavior?

“The whole neural organism, it will be remembered, is, physiologically considered, but a machine for converting stimuli into reactions” (James, 1890, p. 372).

BehaviorBehavior: An analysis of the world, followed by deliberation and : An analysis of the world, followed by deliberation and planning, followed by execution of the plan.planning, followed by execution of the plan.

““sense, think, act”sense, think, act”

motoroutput

sensoryinput

ReactionPerception

representationof the world

Cognition

representationof the motor plan

William James

Source: Paul Cisek

1890

1949

Source: Ken Catania

Pursuit-evasion contests & competition (courtship, predator-prey, territoriality, chess, sports etc.)

H. geographicus

Variability in jumpingRoyan et al., 2010

M. trinitatis

I. Steymans

“The freedom of the will consists in the impossibility of knowing actions that still lie in the future”

Ludwig Wittgenstein

Phototaxis: Gáspár Jékely

Polychaete: Platynereis dumerilii

Max Planck Institute for Developmental Biology

Light Pressure Gravity

benthic

pelagic

Temperature

Salinity

Chemicals

G Jékely et al. Nature 456, 395-399 (2008) doi:10.1038/nature07590

G Jékely et al. Nature 456, 395-399 (2008) doi:10.1038/nature07590

FVRIamide acTub

Cornelia Bargmann 302 neurons, connectome

Gordus et al. 2015, http://dx.doi.org/10.1016/j.cell.2015.02.018

Gordus et al. 2015, http://dx.doi.org/10.1016/j.cell.2015.02.018

Marcus Raichle fMRI

The limiting factor in the evolution of brain size was

energy supply48

49

The additional energy burden associated with […] the environment may be as little as .5-1.0% of the total energy budget.Marcus Raichle (2006): Science 314, p1249

=

Exploration (of resources or solutions.)

Romuald Nargeot

Behavioral variability in a constant stimulus situation:

Actions, not responses

Geometric Random Inner Products: GRIP

All computations Alexander Maye, UKE Hamburg (Maye et al. 2007)

Maye et al. (2007)

If one simple stochastic point process is insufficient, maybe we need more…

Source: This is Spinal Tap

1. Determinism rules out freedom

2. Randomness doesn‘t make us free either

Freedom cannot exist / is a useless concept

Double-Incompatibilists:

Freedom can arise in non-linear systems, comprising stochastic and deterministic components

Deterministic

Stochastic

Determi

nistic

Determi

nistic

Determi

nistic