ndicates that reasons, i.e. premises, are about to be given for a conclusion that has been stated first; "now" which often indicates the beginning of a stage of a multi-stage argument; and "but" which indicates a second premise. Go through the first way and underline such words. About three quarters of the way through the argument notice "therefore" - "therefore, whatever is moved must be moved by another". This is the conclusion that was announced soon after the beginning of the argument, in line 3: "Now whatever is moved must be moved by another, for" - the passage from this "for" down to the "therefore" gives reasons for this intermediate conclusion, which becomes a premise in the last stage of the argument. Go through the other "ways", now, and underline the words that indicate structure, and see if you can get a clear view of the structure of each argument. Notice that each argument ends with something like "and this everyone understands to be God" - this is the meaning of the name God being used as middle term in the final stage of the argument, as foreshadowed in article 2, reply to objection 2, p.105 (Summa theologiae, part 1, q. 2, art. 2). What are the main ideas in these five arguments? The first is about motion, which means every kind of change, not just local motion or change of place, but also ripening, heating, etc: there must always be a cause of any change, a "moving" cause. The second argument is very similar, about "efficient" causes. The difference between a "moving" cause and an "efficient" cause is that the moving cause produces the various stages through which changeable things pass, an efficient cause produces the existence of the thing in each of these stages, and the existence of unchanging things; the moving cause produces another state of something, the efficient cause produces existence. See Supplement, p.72 (Gilson, History of Christian Philosophy, p. 210-211). The ancestor of the first and second ways is A...
