According to Milton, “Logic is the art of reasoning well (‘Logica est ars bene ratiocinandi’).” This glossary compiles a list of logical terms through the multiple stages of logical analysis, so that they can be used in consistent reference to the close readings available on EMNON.

John Milton, Art of Logic, Complete Prose Works ed. by Don Wolfe et al, 8 vols. (New Haven,

CT: Yale University Press, 1956-1982), VIII.217.


Logic: Milton defines logic in his Art of Logic as “the art of reasoning well” (217).

Efficient Cause: “The first of all arguments is cause” (222). “A cause is by the power of which a thing exists” (222). “That power of which a thing not only is, but also was or will be” (222).

Procreating or Maintaining Cause: “…a father and a mother procreate, and a nurse maintains…Procreating and maintaining are therefore two of the ways in which one and the same thing will often function as an efficient cause, procreating that which does not yet exist, and conserving that which already exists so that it may continue to exit” (223).

Impelling Cause: “There are two types of impelling cause…proegumenic or the procatarctic. The first moves the principal cause from within and the second from without” (224).

Instrumental Cause: “…almost all helping and ministering causes can be called instrumental” (225).

Per se: “A per se efficient cause is one which causes efficiently through its own power, that is, one which produces an effect from an intrinsic principle” (226).

Per accidens: “A per accidens efficient cause is one which causes through an external power, that is, one not its own, when the source of the effect is outside the efficient cause and is an external principle as opposed to the internal; for thus the efficient cause acts not through itself but through something else” (227).

Matter: “The cause out of which a thing is” (230). It is the substance acted upon by the efficient cause and can be described as the passive principle, whereas the efficient cause is the active principle.

Form: “The cause through which a thing is what it is” (231). “By its form a thing is distinguished from all other things” (234).

Effect: “An effect is that which exists by reason of its causes” (238).

End: “The cause for the sake of which a thing is” (236). End is the overarching goal and function of a statement.

Argument of Agreement—one which agrees with the thing which it argues. (II.221)

Argument of Disagreement—an argument which disagrees with the thing it argues, namely with another argument of disagreement of the same kind and name (Milton, Complete Prose, .250)

Argument of Comparison–

Human Testimony—that which has a man as its author (Milton, Complete Prose, .320)

Divine Testimony—that which God has as its author (Milton, Complete Prose, .318)

Adjuncts—that of which something is the subject, or that which is relevant to the arguing of a subject (Milton, Complete Prose, .245.)

Privatives—negative contraries, one of which negates only in that subject to which the affirmative by its very nature belongs. (Milton, Complete Prose, VIII.267)


Worked Example



Hark how music then prepares

For thy stay with charming airs;

Which the posting winds recall,

And suspend the river’s fall (37-40).

A Dialogue, Between the Resolved Soul, and Created Pleasure, Andrew Marvell (1681).


Efficient Cause           Music: but is this per se or per accidens?


Matter                         airs


Form                           charming


End                             suspend the river’s fall


Effect                          Music seemingly suspends the Soul from “falling”


Understanding who is the source of music, the temptor “Pleasure” or some outside source, not only determines if music is a per se or per accidens cause, but also determines the plausibility of the effect. Is Pleasure setting up a false logic to trick the Soul into taking his music? How might this alter our reading of their emphasis?