form. Some things are said to be like, which communicate in the same
form according to the same formality, and according to the same mode;
and these are said to be not merely like, but equal in their likeness;
as two things equally white are said to be alike in whiteness; and
this is the most perfect likeness. In another way, we speak of things
as alike which communicate in form according to the same formality,
though not according to the same measure, but according to more or
less, as something less white is said to be like another thing more
white; and this is imperfect likeness. In a third way some things are
said to be alike which communicate in the same form, but not according
to the same formality; as we see in non-univocal agents. For since
every agent reproduces itself so far as it is an agent, and everything
acts according to the manner of its form, the effect must in some way
resemble the form of the agent. If therefore the agent is contained in
the same species as its effect, there will be a likeness in form
between that which makes and that which is made, according to the same
formality of the species; as man reproduces man. If, however, the
agent and its effect are not contained in the same species, there will
be a likeness, but not according to the formality of the same species;
as things generated by the sun's heat may be in some sort spoken of as
like the sun, not as though they received the form of the sun in its
specific likeness, but in its generic likeness. Therefore if there is
an agent not contained in any genus, its effect will still more
distantly reproduce the form of the agent, not, that is, so as to
participate in the likeness of the agent's form according to the same
specific or generic formality, but only according to some sort of
analogy; as existence is common to all. In this way all created
things, so far as they are beings, are like God as the first and
universal principle of all being.