|Life. William of Ockam, Venerabilis Inceptor, Doctor
Invincibilis, is by far the most important philosopher of this
period. He was born at Ockam, in Surrey, about the year 1280. It is
said that he studied at Merton College, Oxford, where it is possible he
had Duns Scotus for teacher.  There seems to be some doubt as to his
having followed the lectures of Scotus at Paris. He taught at Paris
between the years 1320 and 1323. After quitting his chair at Paris, he
threw in his lot with the opponents of the temporal power of the popes,
was imprisoned at Avignon, escaped in 1328, and sought refuge at the
court of Louis of Bavaria, to whom he made the well-known promise: "Tu
me defendas gladio, ego te defendam calamo." It is not known with
certainty where and when he died, but it is probable that he died at
Munich in 1349.
 Cf. Chartul., II, 590.
Sources. Ockam's principal philosophical works are Super Quatuor
Libros Sententiarum, Quodlibeta, Tractatus Logices, and Commentaries on
Aristotle. In addition he wrote several controversial works in
support of the claims of the State against the Church. His
Commentary on the Books of Sentences was published by Trechsel,
at Lyons, in 1495. For bibliography and list of Ockam's controversial
writings, cf. Potthast, Wegweiser, p. 871.
Nominalism. Ockam is best known by his renewal of nominalism. It
would, however, be more correct to describe his doctrine of universals
as a modified conceptualism. In his Commentary on the Books of
Sentences  he enumerates three different opinions concerning
universals, and then continues:
Quarta posset esse opinio quod nihil est universale ex natura sua sed
tantum ex institutione, illo modo quo vox est universalis. Sed haec
opinio videtur non vera.
 Lib. I, Dist. II, Q. VII, E.
In the Tractatus Logices  he formulates his own doctrine that
the universal is an intention of the mind:
Nullum universale est substantia quomodocumque consideretur, sed
quodlibet universale est intentio animae quae secundum unam opinionem
probabilem ab actu intelligendi non distinguitur.
 Pars Ia, cap. 15.
Nevertheless, it is true that Ockam is, in a certain sense, a
nominalist. He maintains, for example, that propositions, not
things, are the objects of scientific knowledge:
Scientia quaelibet, sive sit realis sive rationalis, est tantum de
propositionibus tamquam de illis quae sciuntur, quod solae
propositiones sciuntur. 
 In Ium Sent., Dist. II, Q. IV,
Ockam, therefore, is a conceptualist who uses the language of
nominalism: he does not subscribe to the doctrine that the name
(vox) is alone universal, but, distinguishing between the vox
scripta et prolata and the vox concepta, or the term as it
exists in the mind (intentio animae), he declares that the
latter alone possesses universality. He is a terminist rather than a
nominalist. Ockam, it should be said, devoted special attention
to the development of the logical doctrine of supposition as
formulated in the Summulae of Petrus Hispanus. He would
distinguish, therefore, between the meaning of the word and the
supposition of the term, and would attribute universality to the
supposition as well as to the meaning.
But, although Ockam did not profess the cruder form of nominalism, he
may justly be considered the forerunner of the nominalists who appeared
at the close of the fourth period of the history of Scholasticism.
Psychology. Since the only reality is the individual, the
individual is the only object of knowledge. There is, therefore, no
need of an intermediary species: knowledge takes place by
immediate contact of subject with object: it is intuitive. There is,
indeed, a kind of knowledge which Ockam calls abstractive; this, he
maintains, has nothing to do with really existing things.  All
knowledge of reality is intuitive.
 Quodl., V, 5.
It follows that the active intellect is as useless as are the
species. Ockam, however, preserves the terms active
intellect and passive intellect to designate the active and
passive phases of the activity of the mind:
Intellectus agens et intellectus possibilis sunt omnino idem re et
ratione. Ideo dico quod non est ponenda pluralitas sine necessitate.
 In IIum Sent., Q. XXIV, Q.
The principle here enunciated is known as the Law of Parcimony,
or more commonly as "Ockam's razor."
Ockam distinguishes between the rational soul and the sensitive form in
man. The latter is extended and is corruptible:
Praeter animam intellectivam est ponere aliam formam, scil.
sensitivam, super quam potest agens naturale corrumpendo et producendo:
et ideo non sequitur quod haec esset incorruptibilis. 
 Op. cit., Q. XXII, H.
It is this sensitive soul which is united immediately with the body.
With regard to the rational soul, neither reason nor experience can
prove that the principle of understanding is the
substantial form of the human body. It follows that reason cannot
demonstrate the immortality of the individual soul: Aristotle's
authority cannot be invoked because he speaks hesitatingly: we are
obliged, therefore, to accept these truths as matters of faith.  This
leads to the next point, --
 Quodl., I, 10.
Ockam's Scepticism. Ockam does not deny the possibility of
arriving at certitude. The sceptical tendency in his philosophy
manifests itself in the attempt to restrict the power of human reason.
We have just seen that he relegates the immortality of the soul to the
sphere of faith. In the list of truths which human reason cannot prove
he includes the existence, unity, and infinity of God, and the
immediate creation of the universe by God.  The same peculiar form of
scepticism appears in
 Op. cit., II, 1, and In Ium
Sent., Dist. III, Q. II, F.
His Ethical Doctrines. Ockam, following Scotus, maintains that
right and wrong depend on the will of God, and thus endangers the
necessity and immutability of the principles of morality. "Eo ipso quod
voluntas divina hoc vult, ratio recta dictat quod est volendum." 
 In Ium Sent., Dist. XLI, L.
Historical Position. The principles which Ockam formulated led
to materialistic scepticism. Ockam was, however, saved from the
explicit advocacy of materialism by his belief in the supernatural
order of truth. If we exclude the element of faith and take his
philosophy as it stands, we must pronounce him to be the forerunner of
the anti-Christian philosophers of the Renaissance. He has been
described as the first Protestant. And, indeed, he defended in his
controversial writings the principles subsequently invoked by the
first reformers to justify the encroachments of the secular power. In
philosophy, too, his whole attitude is one of protest against the
prevailing realism, and against the belief that he study of philosophy
can be of material aid to theological sciences. In an age when theism
and spiritualism were universally taught as philosophical tenets, he
protested, in the name of human reason, that belief in God and in the
spirituality of the human soul has no foundation except in