426 Wisconsin Academy of Sciences, Arts, and Letters. 
That is, tlie idea expressed by “life” was not the same at differ^- 
ent stages of his thinking. 
To avoid in your case any chance of such an accident—to 
make sure that in your mind the idea of a, void-filler undergoes 
no variation—my surest course will be to form 1 that idea in your 
mind once only. Moreover, as your thinking will be, so far as 
may be, like my own, I also 1 restrict myself to a single thinking 
of the void-filler. Nevertheless, as argued on pp. 421-423, 
417-420,1 must somehow form in your mind both judgments— 
the one, that I desire you to tell me the void-filler—the other, 
serving to describe the void-filler. 
Under these requirements, the only course I think of is the 
following—a course, moreover, favored by considerations of 
economy. Before one judgment containing the ideia of the void- 
filler fades at all from mind, I must use that idea, in the other 
judgment. That is, I must combine my separate acts of judg¬ 
ing into' one continuous mental operation, consisting of two 
judgments with a simultaneous common factor—that factor be¬ 
ing the idea, of the void-filler. The mental action, in the case 
of my illustration, will accordingly be indicated by the diagram 
I desire you to tell me void-filler 
killed 
Lincoln.* 
ITS OPERATION ON THE HEARER’S MIND. 
Postponing the problem of sententially expressing an inter¬ 
rogative judgment of the present type 1 , let it for the moment be 
assumed that expression is sufficiently effected by my diagram'— 
that I do thereby succeed in revealing to you such a judgment. 
Accordingly you have in mind the interrogative judgment, or 
*The power thus to use an idea, thought of only once, as simulta¬ 
neous element of two different thoughts (a power which, in a Revision 
of the Pronoun, pp. 49-52 I made a somewhat protracted effort to estab¬ 
lish) I will at present merely illustrate objectively, by the case of a 
north-east corner-stone, which is at the same time part of an east wall, 
and part of a north wall, but remains in its double membership a single 
stone. Indeed it seems to me it can be sensed as corner—sensed, I 
mean, with full appreciation—only as it is, by a single mental act, 
appreciated in its two-fold membership of north wall and of south wall. 
