in several parts), or because
some other subject is added sharing in the same form (as when a hot
thing is added to another, or one white thing to another). But in
either of these two ways we have not a more white or a more hot
thing, but a greater white or hot thing.

Since, however, as stated above (A. 1), certain accidents are of
themselves susceptible of more or less, in some of these we may find
increase by addition. For movement increases by an addition either to
the time it lasts, or to the course it follows: and yet the species
remains the same on account of the oneness of the term. Yet movement
increases the intensity as to participation in its subject: i.e. in
so far as the same movement can be executed more or less speedily or
readily. In like manner, science can increase in itself by addition;
thus when anyone learns several conclusions of geometry, the same
specific habit of science increases in that man. Yet a man's science
increases, as to the subject's participation thereof, in intensity,
in so far as one man is quicker and readier than another in
considering the same conclusions.

As to bodily habits, it does not seem very probable that they receive
increase by way of addition. For an animal is not said to be simply
healthy or beautiful, unless it be such in all its parts. And if it
be brought to a more perfect measure, this is the result of a change
in the simple qualities, which are not susceptible of increase save
in intensity on the part of the subject partaking of them.

How this question affects virtues we shall state further on (Q. 66,
A. 1).

Reply Obj. 1: Even in bodily bulk increase is twofold. First, by
addition of one subject to another; such is the increase of living
things. Secondly, by mere intensity, without any addition at all;
such is the case with things subject to rarefaction, as is stated in
_Phys._ iv, text. 63.

Reply Obj. 2: The cause that increases a habit, always effects
something in the subject, but not a new form. But it causes the
subject to partake more perfectly of a pre-existing form, or it makes
the form to extend further.

Reply Obj. 3: What is not already white, is potentially white, as not
yet possessing the form of whiteness: hence the agent causes a new
form in the subject. But that which is less hot or white, is not in
potentiality to those forms, since it has them already actually: but
it is in potentiality to a perfect mode of participation; and this it