powers.  (3) When this has been acquired we shall possess a foundation
wherefrom we can deduce our thoughts, and a path whereby the intellect,
according to its capacity, may attain the knowledge of eternal things,
allowance being made for the extent of the intellectual powers.

[106]  (1) If, as I stated in the first part, it belongs to the nature
of thought to form true ideas, we must here inquire what is meant by
the faculties and power of the understanding.  (2) The chief part of
our method is to understand as well as possible the powers of the
intellect, and its nature; we are, therefore, compelled (by the
considerations advanced in the second part of the method) necessarily
to draw these conclusions from the definition itself of thought and
understanding.

[107]  (1) But, so far as we have not got any rules for finding
definitions, and, as we cannot set forth such rules without a
previous knowledge of nature, that is without a definition of the
understanding and its power, it follows either that the definition
of the understanding must be clear in itself, or that we can
understand nothing.  (2) Nevertheless this definition is not
absolutely clear in itself; however, since its properties, like
all things that we possess through the understanding, cannot be
known clearly and distinctly, unless its nature be known previously,
understanding makes itself manifest, if we pay attention to its
properties, which we know clearly and distinctly.  (3) Let us,
then, enumerate here the properties of the understanding, let us
examine them, and begin by discussing the instruments for research
which we find innate in us. See [31]

[108]  (1) The properties of the understanding which I have chiefly
remarked, and which I clearly understand, are the following:-
I. (2) It involves certainty - in other words, it knows that a thing
   exists in reality as it is reflected subjectively.
II. (108:3) That it perceives certain things, or forms some ideas
   absolutely, some ideas from others.  (4) Thus it forms the
   idea of quantity absolutely, without reference to any other
   thoughts; but ideas of motion it only forms after taking into
   consideration the idea of quantity.
III. (108:5) Those ideas which the understanding forms absolutely
   express infinity; determinate ideas are derived from other
   ideas.  (6) Thus in the idea of quantity, perceived by means
   of a cause, the quantity is determined, as when a body is
   perceived to be formed by the motion of a plane, a plane by
   the motion of a line, or, again, a line by the motion of a
   point.  (7) All these are perceptions which do not serve
   towards understanding quantity, but only towards determining
   it.  (108:8) This is proved by the fact that we conceive them
   as formed as it were by motion, yet this motion is not perceived
   unless the quantity be perceived also; we can even prolong the
   motion to form an infinite line, which we certainly could not do
   unless we had an idea of infinite quantity.
IV. (9) The understanding forms positive ideas before forming
   negative ideas.
V. (108:10) It perceives things not so much under the condition
   of duration as under a certain form of eternity, and in an
   infinite number; or rather in perceiving things it does not
   consider either their number or duration, whereas, in imagining
   them, it perceives them in a determinate number, duration, and
   quantity.
VI. (108:11) The ideas which we form as clear and distinct, seem
   to follow from the sole necessity of our nature, that they
   appear to depend absolutely on our sole power; with confused
   ideas the contrary is the case.  (12) They are often formed
   against our will.
VII. (108:13) The mind can determine in many ways the ideas of things,
which the understanding forms from other ideas: thus, for instance,
in order to define the plane of an ellipse, it supposes a point
adhering to a cord to be moved around two centers, or, again, it
conceives an infinity of points, always in the same fixed relation
to a given straight line, angle of the vertex of the cone, or in an
infinity of other ways.
VIII. (108:14) The more ideas express perfection of any object,
the more perfect are they themselves; for we do not admire the
architect who has planned a chapel so much as the architect who
has planned a splendid temple.

[109] (1) I do not stop to consider the rest of what is referred
to thought, such as love, joy, &c.  (2) They are nothing to our
present purpose, and cannot even be conceived unless the
understanding be perceived previously. (3) When perception is
removed, all these go with it.

[110] (1) False and fictitious ideas have nothing positive about
them (as we have abundantly shown), which causes them to be called
false or fictitious; they are only considered as such through the
defectiveness of knowledge.  (2) Therefore, false and fictitious
ideas as such can teach us nothing concerning the essence of thought;
this must be sought from the positive properties just enumerated;
in other words, we must lay down some common basis from which these
properties necessarily follow, so that when this is given, the
properties are necessarily given also, and when it is removed,
they too vanish with it.

The rest of the treatise is wanting.

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Spinoza's Endnotes: Marks as per Curley, see Note 5 above.
[a] (1) This might be explained more at large and more clearly:
    I mean by distinguishing riches according as they are pursued for
    their own sake, in or furtherance of fame, or sensual pleasure,