Dec 1 Mechanical Philosophy continued: what kinds of theories?
•Speculative accounts of hypothetical corpuscles that might cause phenomena.
•How to invent these theories, how to choose the most plausible, how to sound convincing?
•By analogies with familiar mechanical devices and effects.
–Understand the hidden substratum based on everyday experiences, intuition, illustrations.
Vortex: Cartesian theory of solar system
•Planets are pushed in their orbits as if in a huge whirlpool = vortex theory.
•Plenum = universe is full of matter (void is impossible), and particles impact each other in closed circles.
Magnetic attraction =
caused by corkscrew particles
Light is a secondary quality
(subjective sensation, not real)
•Light is sensed as a pressure against the eye transmitted by particles of the medium.
–Everyday analogy as evidence: press against your eyelid & see light.
•Color is the perceived effect of the motion of particles, spinning slower or faster.
•Descartes’ theory of vision involves mechanical pressure transmitted to back of eye and to brain, causing the figure to be “traced.”
Anything goes?
•Ad hoc tendencies make the MP easy to apply to any specific phenomenon & thus very popular.
–“Posit the existence of sub-microscopic particles of whatever particular shape or size wanted for the purpose.”
•How can such a science be verified or refuted?
•Acids burn because they are composed of sharp pointy corpuscles that scrape. To a mechanical philosopher, this is preferable to Aristotle saying that acids have an “acidic quality.”
•Opium causes sleepiness not because of its “soporific quality,” but because of how its particles affect the brain.
•Keen to explain natural magic without using sympathies, correspondences
–Laying on of hands
–Weapon salve
Descartes’ mind-body dualism
•He rejected authority of ancients, texts, sense experience. Yet still defended Church authority & doctrines, made his science fit.
–Immortal soul & God-given mind & free will
•Animals are mere automata (self-acting machines with biological functions).
•But humans are unique in having both mechanical body AND immaterial soul (res cogitans = thinking stuff).
Automaton (duck) as model for biological processes: only material parts & motions
(Borelli first work based on this comparison)
Pineal gland (?)
•Soul/mind has a special location in the brain = pineal gland.
•Unpublished Treatise on Man, gave hypothetical corpuscular accounts of many physiological processes.
•“We see clocks, artificial fountains, mills, and other such machines which, altho only man-made, have the power to move on their own accord. But I am supposing this machine [human body] to be made by the hands of God, and so capable of a greater variety of movements and exhibiting more artistry…”
Mechanical reflex action vs. vitalism
•Replaces Galen’s “vital faculties” & teleology.
•“Spirits” = subtle particles that flow thru tubes (blood vessels, nerves, valves, pores) & cause functions of organs, muscles.
Science leads to religious heresies?
•Ancient atomism (Epicurus, 300BCE)
–Materialist soul & gods
–No design or purpose
•Revived by mechanical philosophers
–1630s Pierre Gassendi, Catholic priest
–Accepts atoms & void, but rejects atheistic aspects.
•Concerns that Aristotelian science can be materialistic, and magic can be pantheistic (nature = god).
Religious implications of MP
•Clockwork universe that runs by material parts and motions ONLY. Self-operating.
–Any need for God in this system?
–Any place for miracles or providence?
•Deism = Creator as absentee landlord
•Materialism = no immaterial, supernatural explanations
Divine will in a mechanical universe (?)
•Descartes insists YES
–French Catholic
–Moves to Holland in fear of the Inquisition; always paranoid to publish, esp. on cosmology.
–Writes about an “imaginary mechanist cosmos.”
•Keeps God in his physics
–Creator (first cause) of the laws and motion.
–“Conserves” motion of the universe every moment.
Robert Hooke (1635-1703)
•Experiments & instruments for Royal Society of London.
•1665 Microscope & first views of the hidden substructures of objects.
•Evidence for MP = looks different than ordinary experiences, surface appearances.
1665 Micrographia: empirical evidence of divine design at all levels of nature
Robert Boyle (1627-91)
•British experimentalist mechanical philosopher (Boyle’s law of gases).
•Concerned about deistic tendencies of MP, threat to Christian faith.
•World is such a complex, orderly, purposeful clockwork, that it MUST be DESIGNED & TENDED by a wise & caring God (natural theology = handmaiden still).
Isaac Newton (1642-1727)
•Theology a lifelong obsession (secret heretic, interprets biblical prophecies).
•Also made room for ongoing activity of God in his laws of physics
–Creator of precise orbits, etc.
–Periodically restores the matter & motion of the solar system via comets.
–No known cause of gravity, so…