144 Wisconsin Academy of Sciences, Arts and Letters . 
(3) Its central factorships. 
These are theoretically three: as first term, as mid-term, 
as last term—that is, what serves as a factor of lateral thought 
may also be the first or the last or the mid-term of central 
thought. 
Mid-term factorship however does not occur except in cases 
which may be neglected for reasons indicated on pages 114- 
116. 
Last terms Grammar ranks as sometimes adjective and 
sometimes substantive, according as the mid-term is the rela¬ 
tion of substance to its own attribute (as in “Roses are red”), 
or some other relation. Continuing to regard the nature of 
thought-membership as the only adequate ground for differen¬ 
tiating parts of speech, I neglect this distinction. I confine 
myself, however, in the interest of clearness, to the case in 
which the last term is by Grammar ranked as substantive. 
Both the first and last terms, with the above exception, Gram¬ 
mar ranks as substantive. As it is not now important to differ¬ 
entiate their services in thought construction, I accept them as 
one species, restricting examination to the more convenient case 
in which a term of lateral thought is also last term of a cen¬ 
tral thought. 
(I) Its lateral factorships. 
These are plainly three: as first term, as mid-term, as last 
term. That is, what serves as factor of central thought may 
be the first or last or mid-term of lateral thought. 
As indicated on pages 142 and 143, whichever lateral factor 
is also central factor, it will be still attended by its lateral fel¬ 
lows. Accordingly, in its cooperation with central thought to 
form a larger mental total, the lateral thought will pose before 
the mind as 
(a) a mid-term attended by first and last terms (or, say, a 
relation between two terms)—or 
(b) a first term attended by mid-term and last term—or 
(c) a last term attended by first term and mid-term. 
