Leibniz s Monads and DNA

1. Leibniz�s Monads and DNA George MacDonald Ross University of Leeds

2. Who was Leibniz? First major German philosopher 1646-1716 (contemporary of John Locke) Main influences: Thomas Hobbes Descartes & Spinoza Other influences: Ancient and scholastic philosophy Well connected with lesser contemporaries

3. What are monads? - 1 �Monad� means both �unit� and �unity�: as units: the ultimate constituents of reality; as unities: simple, indivisible, organic wholes. The model for monads is the human soul The human soul is characterised by: reason (self-)consciousness (�apperception�) perception volition (�appetition�)

4. What are monads? - 2 Other monads are not humans They lack reason and consciousness But they do have: unconscious perceptions (�petites perceptions�) unconscious appetition, or striving towards a better state Leibniz sometimes calls them �spiritual atoms�

5. Why monads? The theory seems crazy. So why monads? New solution to the problem of what the universe consists in Two issues: is there one kind of substance, or two (mind and matter)? is the material world a compound of atoms, or a plenum divisible into infinitely many parts?

6. One kind of substance or two? For Descartes, there are both mind and matter. But: how can they interact? how can they be united to form an individual person? For Hobbes, there was only matter. But: how can he explain consciousness? For Spinoza, the only substance was God. But: heresy!!!

7. Leibniz�s solution Only spiritual substances exist, and matter belongs only to our perceptual world (phenomenalism) No problem of interaction between different kinds of substance Consciousness is not a product of matter, but a gift of God to human monads Individual substances are kept distinct from God

8. Are there atoms? Atomists (Democritus, Gassendi) held that the material world consists of material atoms moving in empty space. But: why can�t atoms be subdivided? how can one atom transfer a force to another? how can empty space exist, if it has no substance or properties?

9. Is there a plenum? Most believed in a plenum (Hobbes, Descartes, Spinoza) It seemed obvious because: the concept of empty space is incoherent light and gravitation pass through an apparent vacuum But: if things are just part of matter as a whole, they are not genuine substances there is no way of distinguishing things

10. Leibniz�s solution There is indeed a plenum But it is composed of infinitely small parts, which can always be further subdivided These parts are the bodies of living organisms, and every organism is a colony of smaller organisms Bodies are only phenomenal, and the ultimate realities are the souls which constitute the unity of each organism.

11. How do monads relate to their organic bodies? Each monad is the principle of unity of an organic body The monad of a larger body �dominates� those of the smaller bodies of which it is composed The parts of the same organism belong together because their characteristics are uniquely related to their monad

12. How does this relate to DNA? The parts of a body are not held together spatially, because space is unreal They are held together by characteristics which relate them to just one monad, and no other Even if they become detached, the characteristics remain As with DNA, it is in principle possible to discover which organism they belonged to.

13. Conclusion Leibniz did not discover DNA The discovery of DNA surprised modern scientists, because they could not conceive that the tiniest parts of an individual organism could be unique to it Leibniz would not have been surprised, since the idea was central to his philosophy