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asleep as when you are awake。
Well； now； you cannot at the moment answer that kind of reasoning。
You feel that your worthy friend has you somewhat at a
disadvantage。 You will feel perfectly convinced in your own mind；
however； that you are quite right； and you say to him； 〃My good
friend； I can only be guided by the natural probabilities of the
case； and if you will be kind enough to stand aside and permit me
to pass； I will go and fetch the police。〃 Well； we will suppose
that your journey is successful； and that by good luck you meet
with a policeman； that eventually the burglar is found with your
property on his person； and the marks correspond to his hand and to
his boots。 Probably any jury would consider those facts a very
good experimental verification of your hypothesis； touching the
cause of the abnormal phenomena observed in your parlor； and would
act accordingly。
Now； in this supposititious case； I have taken phenomena of a very
common kind； in order that you might see what are the different
steps in an ordinary process of reasoning； if you will only take
the trouble to analyse it carefully。 All the operations I have
described； you will see； are involved in the mind of any man of
sense in leading him to a conclusion as to the course he should
take in order to make good a robbery and punish the offender。 I
say that you are led； in that case； to your conclusion by exactly
the same train of reasoning as that which a man of science pursues
when he is endeavouring to discover the origin and laws of the most
occult phenomena。 The process is； and always must be； the same；
and precisely the same mode of reasoning was employed by Newton ＇90＇
and Laplace ＇91＇ in their endeavours to discover and define the causes
of the movements of the heavenly bodies； as you； with your own common
sense； would employ to detect a burglar。 The only difference is；
that the nature of the inquiry being more abstruse； every step has
to be most carefully watched； so that there may not be a single
crack or flaw in your hypothesis。 A flaw or crack in many of the
hypotheses of daily life may be of little or no moment as affecting
the general correctness of the conclusions at which we may arrive；
but； in a scientific inquiry； a fallacy； great or small； is always
of importance； and is sure to be in the long run constantly
productive of mischievous if not fatal results。
Do not allow yourselves to be misled by the common notion that an
hypothesis is untrustworthy simply because it is an hypothesis。 It
is often urged； in respect to some scientific conclusion； that；
after all； it is only an hypothesis。 But what more have we to
guide us in nine…tenths of the most important affairs of daily life
than hypotheses； and often very ill…based ones？ So that in
science； where the evidence of an hypothesis is subjected to the
most rigid examination； we may rightly pursue the same course。 You
may have hypotheses； and hypotheses。 A man may say； if he likes；
that the moon is made of green cheese： that is an hypothesis。 But
another man； who has devoted a great deal of time and attention to
the subject； and availed himself of the most powerful telescopes
and the results of the observations of others； declares that in his
opinion it is probably composed of materials very similar to those
of which our own earth is made up： and that is also only an
hypothesis。 But I need not tell you that there is an enormous
difference in the value of the two hypotheses。 That one which is
based on sound scientific knowledge is sure to have a corresponding
value； and that which is a mere hasty random guess is likely to
have but little value。 Every great step in our progress in
discovering causes has been made in exactly the same way as that
which I have detailed to you。 A person observing the occurrence of
certain facts and phenomena asks； naturally enough； what process；
what kind of operation known to occur in Nature applied to the
particular case； will unravel and explain the mystery？ Hence you
have the scientific hypothesis； and its value will be proportionate
to the care and completeness with which its basis had been tested
and verified。 It is in these matters as in the commonest affairs
of practical life： the guess of the fool will be folly； while the
guess of the wise man will contain wisdom。 In all cases； you see
that the value of the result depends on the patience and
faithfulness with which the investigator applies to his hypothesis
every possible kind of verification。
ON THE PHYSICAL BASIS OF LIFE ＇92＇
In order to make the title of this discourse generally
intelligible； I have translated the term 〃Protoplasm；〃 which is the
scientific name of the substance of which I am about to speak； by
the words 〃the physical basis of life。〃 I suppose that； to many；
the idea that there is such a thing as a physical basis； or matter；
of life may be novelso widely spread is the conception of life as
a something which works through matter； but is independent of it；
and even those who are aware that matter and life are inseparably
connected； may not be prepared for the conclusion plainly suggested
by the phrase； 〃THE physical basis or matter of life；〃 that there
is some one kind of matter which is common to all living beings；
and that their endless diversities are bound together by a
physical； as well as an ideal； unity。 In fact； when first
apprehended； such a doctrine as this appears almost shocking to
common sense。
What； truly； can seem to be more obviously different from one
another； in faculty； in form； and in substance； than the various
kinds of living beings？ What community of faculty can there be
between the bright…coloured lichen； which so nearly resembles a
mere mineral incrustation of the bare rock on which it grows； and
the painter； to whom it is instinct with beauty； or the botanist；
whom it feeds with knowledge？
Again； think of the microscopic fungusa mere infinitesimal ovoid
particle； which finds space and duration enough to multiply into
countless millions in the body of a living fly； and then of the
wealth of foliage； the luxuriance of flower and fruit； which lies
between this bald sketch of a plant and the giant pine of
California； towering to the dimensions of a cathedral spire； or the
Indian fig； which covers acres with its profound shadow； and
endures while nations and empires come and go around its vast
circumference。 Or； turning to the other half of the world of life；
picture to yourselves the great Finner whale；＇93＇ hugest of beasts
that live； or have lived； disporting his eighty or ninety feet of bone；
muscle and blubber； with easy roll； among waves in which the
stoutest ship that ever left dockyard would flounder hopelessly；
and contrast him with the invisible animalculesmere gelatinous
specks； multitudes of which could； in fact； dance upon the point of
a needle with the same ease as the angels of the Schoolmen could；
in imagination。 With these images before your minds； you may well
ask； what community of form； or structure； is there between the
animalcule and the whale； or between the fungus and the fig…tree？
And； a fortiori；＇94＇ between all four？
Finally； if we regard substance； or material composition； what
hidden bond can connect the flower which a girl wears in her hair
and the blood which courses through her youthful veins； or； what is
there in common between the dense and resisting mass of the oak； or
the strong fabric of the tortoise； and those broad disks of glassy
jelly which may be seen pulsating through the waters of a calm sea；
but which drain away to mere films in the hand which raises them
out of their element？
Such objections as these must； I think； arise in the mind of every
one who ponders； for the first time； upon the conception of a
single physical basis of life underlying all the diversities of
vital existence； but I propose to demonstrate to you that；
notwithstanding these apparent difficulties； a threefold unity
namely； a unity of power or faculty； a unity of form； and a unity
of substantial compositiondoes pervade the whole living world。
No very abstruse argumentation is needed； in the first place to
prove that the powers； or faculties； of all kinds of living matter；
diverse as they may be in degree； are substantially similar in
kind。
Goethe has condensed a survey of all powers of mankind into the
well…known epigram：＇95＇
〃Warum treibt sich das Volk so und schreit？ Es will sich ernahren
Kinder zeugen； und die nahren so gut es vermag。
。 。 。 。 。 。 。 。 。 。 。 。 。
Weiter bringt es kein Mensch； stell' er sich wie er auch will。〃
In physiological language this means； that all the multifarious and
complicated activities of man are comprehensible under three
categories。 Either they are immediately directed towards the
mainten