the different parts of a single complex sense-datum.
For example, I can see at a glance the whole of the page on which I
am writing; thus the whole page is included in one sense-datum. But I
perceive that some parts of the page are to the left of other parts,
and some parts are above other parts. The process of abstraction in this
case seems to proceed somewhat as follows: I see successively a number
of sense-data in which one part is to the left of another; I perceive,
as in the case of different white patches, that all these sense-data
have something in common, and by abstraction I find that what they have
in common is a certain relation between their parts, namely the relation
which I call 'being to the left of'. In this way I become acquainted
with the universal relation.

In like manner I become aware of the relation of before and after in
time. Suppose I hear a chime of bells: when the last bell of the chime
sounds, I can retain the whole chime before my mind, and I can perceive
that the earlier bells came before the later ones. Also in memory I
perceive that what I am remembering came before the present time. From
either of these sources I can abstract the universal relation of before
and after, just as I abstracted the universal relation 'being to the
left of'. Thus time-relations, like space-relations, are among those
with which we are acquainted.

Another relation with which we become acquainted in much the same way is
resemblance. If I see simultaneously two shades of green, I can see
that they resemble each other; if I also see a shade of red: at the same
time, I can see that the two greens have more resemblance to each other
than either has to the red. In this way I become acquainted with the
universal _resemblance_ or _similarity_.

Between universals, as between particulars, there are relations of which
we may be immediately aware. We have just seen that we can perceive
that the resemblance between two shades of green is greater than the
resemblance between a shade of red and a shade of green. Here we are
dealing with a relation, namely 'greater than', between two relations.
Our knowledge of such relations, though it requires more power of
abstraction than is required for perceiving the qualities of sense-data,
appears to be equally immediate, and (at least in some cases) equally
indubitable. Thus there is immediate knowledge concerning universals as
well as concerning sense-data.

Returning now to t