Written on 31.01.2005,
by Roman Zakharii, in

My son, preserve sound judgement and discernment, do not let them out of your sight,
they will be life for you, an ornament to grace your neck.
Then you will go on your way in safety, and your foot will not stumble.

In Old Hebrew: Netzor tusheya u-mezima.
Ve-yiheyu chaim nafeshecha ve-chen le-garegoteycha.
Az-teleech lavetach darekecha ve-rageleycha. Lo tigeof!

The Book of Proverbs (Mishley)  3:21-23




On how to improve your understanding and mental faculty


My selected passages of Thomas Aquinas' articles
on the vices  opposed to knowledge and understanding with certain remarks of mine


On Blindness of Mind and Intellectual Faculty


Gregory  (Moral. 31, 45) reckons blindness of mind among the vices arising from lust. I (Thomas Aquinas) answer that, just as bodily blindness is the privation of the principle of bodily sight, so blindness of mind is the privation of the principle of mental or intellectual sight.

Now this (intellectual sight) has a threefold principle:

1. One is the light of
natural reason, which light, since it pertains to the species of the rational soul, is never forfeit from the soul, and yet at times, it is prevented from exercising its proper act. Through being HINDERED BY THE LOWER POWERS which the Human intellect needs in order to understand, for instance in the case of imbeciles and madmen. The blindness that excuses from sin is
that which arises from the natural defect of one who cannot see.

2. Another principle of intellectual sight is a certain
habitual light superadded to the natural light of reason, which light is sometimes forfeit from the soul. This privation is blindness, and is punishment, in so far as the privation of the light of grace is a punishment.

3. A third principle of intellectual sight is an
INTELLIGIBLE PRINCIPLE, through which a man understands other things; to which principle a man may attend or not attend.  That he does not attend thereto happens in two ways: Sometimes it is due to the fact that a man's will is deliberately turned away from the consideration of that principle, whereas sometimes it is due to the mind being more busy about things which it loves more, so as to be hindered thereby from considering this principle, according to Psalm 57:9, Fire, (i.e. of concupiscence), hath fallen on them and they shall not see the sun. In either of these ways blindness of mind is a sin.

To understand the truth is, in itself, beloved by all; and yet, accidentally it may be hateful to someone, in so far as a man is hindered thereby from having what he loves yet more.

On Dullness of (understanding related) Senses:

Aquinas on dullness of sense which is connected with understanding

(Non-ability to draw conclusion from properties or effects of what one sees or hears is meant)

Dull is opposed to sharp: and a thing is said to be sharp because it can pierce; so that a thing is called dull through being obtuse and unable to pierce. Now a bodily sense, by a kind of metaphor, is said to pierce the medium, in so far as it perceives its object from a distance or is able by penetration as it were to perceive the smallest details of the inmost parts of a thing. Hence in corporeal things the senses are said to be acute when they can perceive a sensible object from afar, by sight, hearing, or scent, while on the other hand they are said to be dull, through being unable to perceive, except sensible objects that are near at hand, or of great power.

Now, by way of similitude to bodily sense, we speak in sense in connection with the intellect; and this latter sense is in respect of certain primals and extremes, even as the senses are cognizant of sensible objects as of certain principles of knowledge. Now the sense which is connected with understanding, does not perceive its object through a medium of corporeal distance, but through certain other media, as, for instance when it perceives through a property (f.e. ability to draw mental conclusions from what one sees or hears). Consequently a man is said to have an acute sense in connection with his understanding, if, as soon as he apprehends a property or effect of a thing, he understands the nature of the thing itself, and if he can succeed in perceiving its slightest details: whereas a man is said to have a dull sense in connection with his understanding,
if he cannot arrive at knowing the truth about a thing, without many explanations; in which case, moreover, he is unable to obtain a perfect perception of everything pertaining to the nature of that thing.

Accordingly dullness of sense in connection with understanding denotes certain
weakness of the mind as to the consideration of spiritual goods; while blindness of mind implies the complete privation of the knowledge of such things. Both are opposed to the gift of understanding, whereby a man knows spiritual goods by apprehending them, and has a subtle penetration of their inmost nature. This
dullness has a character of sin, just as blindness of mind has, that is, in so far as it is evidenced in one  who, owing to his affection for carnal things, dislikes or
neglects the careful consideration of spiritual things.


Gregory says (Moral 331, 45) that
dullness of (understanding) sense arises from gluttony and blindness of mind from lust.

I (Thomas Aquinas) answer that, the perfect intellectual operation in man consists in an abstraction from sensible phantasms, wherefore
the more a man's intellect is freed from those phantasms, the more thoroughly will it be able to consider things intelligible, and set in order all things sensible.

Thus Anaxagoras stated that
intellect requires to be "detached" in order to command, and that the agent must have power over matter, in order to be able to move it. Now it is evident that pleasure fixes a man's attention on that which he takes pleasure in: wherefore the Philosopher says that we all do best that which we take pleasure in doing, while as to other things, we do them either not at all, or in a faint-hearted fashion.

For this reason these vices cause man's attention to be firmly fixed on corporeal things, so that in consequence man's operation in regard intelligible things is weakened, more however, by lust than gluttony, which makes man weak in regard to the same intelligible things. On the other hand, the contrary virtues, viz. abstinence and chastity, dispose man very much to the perfection of intellectual operation.

The flesh acts on the intellective faculties, not by altering them, but by impeding their operation in the aforesaid manner.


Although some who are the slaves of carnal vices are at times capable of subtle considerations about intelligible things, on account of the perfection of their natural genius, or of some habit superadded thereto, nevertheless, on account of the pleasure of the body, it must needs happen that their attention is frequently withdrawn from this subtle contemplation: wherefore the unclean can know some truths, but their uncleanness is a clog on their knowledge.


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Smerten er ond, enten for kroppen – la da kroppen ytre seg om det.
Eller for sjelen. Men sjelen er i stand til å bevare sin uforstyrrelig ro,
og nekte å oppfatte smerten som noe ondt. Vurdering, initiative,
begjær, avvisning, alt skjer i ends indre. Intet ondt kan tvinge seg inn der.


Pain is bad, either for the body – let the body to express itself on that.
Or for the soul. But the soul is capable to maintain its undisturbable calmness,
and neglect to perceive pain as something bad.  
Analyzing, initiative,
 rejection, desire, all this happens in its (soul’s) inner part.
No evil can force itself inside there.


Marcus Aurelius, Roman emperor (121 – 180)
“Til Meg Selv” (To Myself). Kleanthes. Hymne. Oslo, 1997


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Created by Roman Zakharii on 31.01.2005 in Norway. Updated in 2013 in Iceland.

My e-mail is roman800@gmail.com


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