which have heating and chemical properties. These `lights' are called
infra-red and ultra-violet.
Intelligence& MentalImage:Allof us are awareof ourselves, i.e., we
perceivethatweexist;andwealsoarriveatconceptsinagradualman-
nerconcerningmattersoutsideourselveswhichweexplainbythiskind
ofstatement: “Isolvedthe mostdifficultmathematicalproblem.”Also,
manis awareof his own knowledge:heknows that heknows.Intelli-
genceisnotsomethingvisibleoraudibleinthesensethatmancanseeit
with hiseyes orhear itwith his ears;buteveryonefinds itin himself.
Otherscannotlearn about my intelligence through thefive senses, but
they can deduceitspresence from the effectitproduces. Forexample,
whenascientistisexpoundingonaproblem,itbecomesclearthathehas
understood it.
Peoplecanconstructintheirownmindsanyformthattheywish,e.g.,
a tower similar to the EiffelTower whose construction in the external
worldrequiredmanyyears,athousandsortsofdifferentbuildingmater-
ials andsubstances, and hundredsof workers; this can be built in the
mindinaninstant.Itisclearthatotherscannotbeinformeddirectlyof
thecreationsofourminds,becausetheyarenotvisibleandaudible,but
they can discover their existence from our speech.
Life:Abeautifulchicken,movingtowardsthewater,fallsintoapond,
and,beforewecanrescueit,itdies.Atthisverymoment,whatchange
hastakenplaceinthechicken;andwhatdifferencehasoccurredthatit
no longer moves, plays or eats?
Theresurelywassomethinginthelivechickenbutwhichdoesnotex-
istinthedead—lifeitself.Lifeisnotanobjectofthesenses.Weonlyper-
ceivetheeffects of life:movement,feeding,etc., andfrom theseeffects
we discover its existence.
* * *The facts mentioned above make it thoroughly clear that over and
abovethebeingsthatweperceivewithoursensoryorgans,therearealso
thingswhichwedonotdirectlyperceive,butweknowaboutthemonly
through the effects they produce.