Download Dec 1 Mechanical Philosophy continued: what kinds of theories

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• Unpublished Treatise on Man, gave hypothetical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…