<A>
Resaïna
see map below, centre, circled Resh Ayna
<B>
Pombaditha
see map below, lower centre, circled next to Anbar
<C>
Albert of Saxony: *
He combined critical analysis of language with epistemological pragmatism; like Burudan he distinguishes between the absolutely impossible with what is impossible “in the common course of nature” & considered hypotheses under circumstances that are not naturally possible but imaginable given God's absolute power. He refused to extend the reference of a physical term to supernatural. Regarded as a nominalist, the wide circulation of his works made him a better-known than either Buridan or Oresme, both contemporaries, both nominalists. Albert's work in logic reflects Ockham, whose commentaries on the logica vetus (i. e. on Porphyry, and Aristotle's Categoriae and De interpretatione) were made the subject in a of a series of works he called Quaestiones..
the theory of Impetus and Albert of Saxony
Albert of Saxony's teachings on logic and metaphysics were extremely influential. The theory of impetus introduced a 3rd stage to the 2 stage theory of Avicenna.
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see illustrationleft:
InitialA to B: first stage. Motion is in a straight line in direction of impetus which is dominant while gravity is insignificant
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B to C: Intermediate stage. Path begins to deviate downwards from straight line as part of a great circle as air resistance slows projectile and gravity recovers.
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C to D: last stage. Gravity alone draws projectile downwards vertically as all impetus is spent.
This theory was a precursor to the modern theory of inertia.
<D>
Buridan: *
Aristotle held that a body was maintained in motion only by the action of a continuous external force. Thus (according to Aristotle) a projectile moving through the air would owe its continuing motion to eddies or vibrations in the surrounding medium, a phenomenon known as antiperistasis; in the absence of a proximate force, the body would come to rest almost immediately. A counter theory first found in Avicenna & John Philoponus, was theory of impetus: motion was maintained by some property of the body imparted when it was set in motion. Although not the first to come up with the idea, he was the first to name this motion-maintaining property impetus. Buridan asserted that a body would be arrested by the forces of air resistance and gravity, rejecting the earlier view that the impetus dissipated spontaneously. Buridan also held that the impetus of a body increased with the speed with which it was set in motion & with its quantity of matter. His theory closely resembles the modern concept of momentum.