4.4.4, Mr Norbert Wiener, A Contribution to the 
: Reconex.>.R|(-=£R+R)|R= R29 (e@=y)|R 
Rae 
=R\R (2) 
+: Reser.D>.R\(+R=R)| RGR. ReRI. 
D.Recs (3) 
fe (3) erser Ges: 
Moreover, it has been shown by Mr Russell that it is advan-_ 
tageous for purposes of methodological simplicity to regard the 
instants of time as constructions from its events. This is an 
additional reason for starting from the members of cs and forming 
‘certain members of ser as functions of them. Let us, then, agree 
that an instant, for example, is to be regarded as a class of events, 
and a point on a line as a class of the segments of the line, for the 
purposes of this paper. The question then arises, when is a class 
of events an instant, and when is a class of segments a point? It 
is obvious on inspection that not every class of events is an instant: 
all the events which make up a given instant must be simultaneous 
with one another, and all the events which are simultaneous with 
every member of the instant must belong to that instant. More- 
over, A must not be.an instant. It can also be seen readily that 
any class satisfying these conditions will be an instant. That is, 
if P is the relation of an event to an event which completely follows 
it, it is a simple matter to show that the class of all instants is 
—> 
eS we oe 
One instant precedes another when and only when some event 
belonging to the one entirely precedes some event belonging to 
the other. That is, calling the relation of precedence between 
instants inst‘P, we can easily show that we have 
v => 
Pe inst]2 —(e922)\p@ (= pleases 
Let me now make the following definitions for any value 
of P: 
=—_> 
SOUR, goa GS pe. Df. 
PhO a OM (622) can De 
I wish to show that 
L. inst“ (R| R,,| R GR} Cser, 
* This definition is due to Mr Russell. 
