26 Owen—Meaning and Function of Thought- Connectives. 
to focus attention upon relations comes late and the words which 
distinctly express relations are late in linguistic development. 
In fact the perfect differentiation of one relation from another 
would be a maximum of intellectual attainment. It is, therefore, 
readily conceded that the suggested lines of demarcation be¬ 
tween classes of relation are more or less arbitrary. Classifica¬ 
tion is accordingly made in the interest, mainly, of convenience. 
It should further be noted that, on account of the general lack of 
power to clearly discriminate between relations, there is much 
inconsistency in the use of relation-naming words. The same 
word stands for different relations and different words stand for 
the same relation. There will then be no attempt to exhaust 
the possibilities of relation-naming, the present aim being not 
so much to establish meaning as to exhibit structure. 
The relation most frequently expressed by thought-connectives 
may be known as common group-membership. In treating this 
relation it is important to distinguish at once the different 
aspects in which a group may be considered. 
In the first place the same group may be conceived as either 
homogeneous or heterogeneous. For instance, the difference 
between two objects being emphasized, they may be called 
“ an apple and a pear. ” The group in this case is conceived as 
heterogeneous. On the other hand, their differences being over¬ 
looked, they may be called “ two fruits. ” The same group is 
now conceived as homogeneous. Omitting the interesting pos¬ 
sibilities of groups formable either in time or space from ob¬ 
jects, qualities, actions and relations, I merely draw from my 
illustration the general principle that homogeneous idea-groups 
may be expressed by plurals. 
Homogeneous thought-groups are somewhat rare. As would 
be expected from the expression of thought-adjuncts by mid-berm- 
adjuncts (see p. 22), it appears that the indication of thought- 
plurality may be accomplished by indicating plurality of mid¬ 
term or relation-word. To illustrate, suppose a homogeneous 
series or group of visits on my part to my uncle; a single one 
of these may be expressed by the sentence: “ I visited my uncle. u 
If I wish to pluralize this in English, I do so by a pluralizing 
