what is life

Alfred Driessen Electrical Engineering and Applied Physics

801what-is-life.ppt slide 1 date: 5 January 2008What is life?

What is life?What is life?What is life?

Alfred DriessenAlfred DriessenUniversity of TwenteUniversity of Twente

[email protected]@utwente.nl



Content

What is life?

1. Introduction

2. What can we learn from philosophy?

3. More is different (P.W. Anderson)

4. Philosophical reflections

5. Conclusions



Game of Life (Conway 1970)

Game of life: Cellular Automaton

Rules1. Any live cell with fewer than two live

neighbours dies, as if by loneliness.

2. Any live cell with more than three live neighbours dies, as if by overcrowding.

3. Any live cell with two or three live neighbours lives, unchanged, to the next generation.

4. Any dead cell with exactly three live neighbours comes to life.



Powers of ten (movie 1977)



Unity of living objectscomparison stone and living object (cow)division of stone: result two (smaller) stones

division of cow: two parts of a cow's cadaver



View of Science on LifeP.W. Anderson*): hierarchy of sciences according to:elementary entities of science X obey the laws of science Y

Does this imply science X is applied science Y?*) Science, 177, pp 393-396 (1972)



The vision of philosophers

Raphael, the school of Athens (Vatican museum)



Life according to Aristotle (384-322 BC)

By life we mean self-nutrition and growth with its correlative decay.De anima, book II,

Three levels: plants, animals, human beings

How to explain unity of living object?

Aristotle: hylomorphismLife is supported by a principle of life, the form (Greek morphe) which informs a certain material (hylo) such that it is a living organism. Form of living object: psyche (soul)

That what is real is the whole, the parts exist only virtually.What is the difference between real and virtual? Has to be determined by experience



A modern analogue to material and formhardware - softwaresoftware is always implemented in some hardware,for example: program file: on memory-stick

on CDon hard-diskas code written on paper

hardware, which is switched-on, has always certain information, i.e. softwarefor example: tv monitor movie

tele-text'snow' if only noise at input

In Aristotelian language: information, the form, has to be implemented in some kind of hardware, the material, otherwise it is not real, it is virtual, virtual reality



P.W. Anderson: More is different*)

Theoretical Physicist, born: 1923, Nobel prize 1977

Distinction between reductionism and constructionism

The reductionist hypothesis does not by any means imply a "constructionist" one: The ability to reduce everything to simple fundamental laws does not imply the ability to start from those laws and reconstruct the universe.

*) Science, 177, pp 393-396 (1972)



Example I: a mechanical clockThe clock and its parts: once assembled, all parts are clearly visible and distinguishable



Example II: quantum mechanical systemQuantum mechanics:there are systems, that can be decomposed in its parts; as long as the system remains, however, the parts can not be distinguished, neither theoretically nor experimentally

examples:-- superconductivity: Bose-Einstein condensation of Cooper pairs

-- superfluidity: Bose-Einstein condensation of helium atoms

-- entangled photons

technical term: superposition, the particles are in a superposition state



Philosophical reflectionThere are two ways of considering the relation between the whole and its parts:

I) The whole adds nothing essential to the parts and the fundamental laws governing these.Extreme statement: Der Mensch ist was er ißt (Karl Marx)(Man is what he is eating)

II) The whole has something (new laws, for example) beyond the constitutive parts and the laws governing these.

In both cases, the whole can be reduced to its parts; in II) the whole can not be constructed from the parts without additional input.



Philosophical reflection about lifeThere is a strong unity exclusively observed in living objects.

Already in some relatively simple systems unity can not constructed exclusively from its parts and the laws governing these.

It should be expected that the most complex systems known to us, i.e. living objects, can also not be constructed from its parts and the laws governing these.

This line of argumentation is supported by:AristotleQuantum mechanicseveryday experience

what is life

Automotive

bcby life

principle of life

game of life conway

live cell

form of living object

view of science

live neighbours lives

living organism