464 
NATURE 
| SEPTEMBER II, 1902 
twenty-eight years that have elapsed since the last visit of the 
British Association, Belfast has become first a city and then a 
county, and now ranks as one of the eight largest cities in the 
United Kingdom. Its municipal area has been considerably 
extended, and its population has increased by something like 
75 percent. It has not only been extended, but improved and 
beautified in a manner which very few places can match, and 
which probably none can surpass. Fine new thoroughfares, 
adorned with admirable public institutions, have been run 
through areas once covered with crowded and squalid buildings. 
Compared with the early fifties, when iron shipbuilding was 
begun on a very modest scale, the customs collected at the 
port have increased tenfold. Since the introduction of the 
power-loom, about 1850, Belfast has distanced all rivals in the 
linen industry, which continues to flourish notwithstanding the 
fact that most of the raw material is now imported, instead of 
being produced, as in former times, in Ulster. Extensive im- 
provements have been carried out in the port at a cost of several. 
millions, and have been fully justified by a very great expansion 
of trade. These few bare facts suffice to indicate broadly the 
immense strides taken by Belfast in the last two decades. For 
an Association that exists for the advancement of science it is 
stimulating and encouraging to find itself in the midst of a 
vigorous community, successfully applying knowledge to the 
ultimate purpose of all human effort, the amelioration of the 
common lot by an ever-increasing mastery of the powers and 
resources of Nature. 
Tyndall and Evolution. 
The Presidential Address delivered by Tyndall in this city 
twenty-eight years ago will always rank as an epoch-making 
deliverance. Of all the men of the time, Tyndall was one of 
the best equipped for the presentation of a vast and complicated 
scientific subject to the mass of his fellow-men. Gifted with 
the powers of a many-sided original investigator, he had at the 
same time devoted much of his time to an earnest study of 
philosophy, and his literary and oratorical powers, coupled with 
a fine poetic instinct, were qualifications which placed him in 
the front rank of the scientific representatives of the later 
Victorian epoch, and constituted him an exceptionally endowed 
exponent of scientific thought. In the Belfast discourse Tyndall 
dealt with the changing aspects of the long unsettled horizon of 
human thought, at last illuminated by the sunrise of the doctrine 
of evolution. The consummate art with which he marshalled 
his scientific forces for the purpose of effecting conviction of the 
general truth of the doctrine has rarely been surpassed. The 
courage, the lucidity, the grasp of principles, the moral enthu- 
siasm with which he treated his great theme have powerfully 
aided in effecting a great intellectual conquest, and the victory 
assuredly ought to engender no regrets. 
Tyndall’s views as a strenuous supporter and believer in the 
theory of evolution were naturally essentially optimistic. He 
had no sympathy with the lugubrious pessimistic philosophy 
Whose disciples are for ever intent on administering rebuke to 
scientific workers by reminding them that, however much know- 
ledge man may have acquired, it is as nothing compared with 
the immensity of his ignorance. That truth is indeed never 
adequately realised except by the man of science, to whom it is 
brought home by repeated experience of the fact that his most 
promising excursions into the unknown are invariably terminated 
by. barriers which, for the time at least, are insurmountable. 
He who has never made such excursions with patient labour 
may indeed prattle about the vastness of the unknown, but he 
does so without real sincerity or intimate conviction. His tacit, 
if not his avowed, contention is, that since we can never know 
all it is not worth while to seek to know more; and that in 
the profundity of his ignorance he has the right to people the 
unexplored spaces with the phantoms of his vain imagining. 
The man of science, on the contrary, finds in the extent of his 
ignorance a perpetual incentive to further exertion, and in the 
mysteries that surround him a continual invitation, nay, more, 
an inexorable mandate. Tyndall’s writings abundantly prove 
that he had faced the great problems of man’s existence with 
that calm intellectual courage the lack of which goes very far to 
explain the nervous dogmatism of nescience. Just because he 
had done this, because he had, as it were, mapped out the 
boundaries between what is knowable though not yet known and 
what must remain for ever unknowable to man, he did not hesitate 
to place implicit reliance on the progress of which man is 
capable, through the exercise of patient and persistent research. 
NO. 1715, VOL. 65] 
In Tyndall’s scheme of thought the chief dicta were the strict 
division of the world of knowledge from that of emotion, and 
the lifting of life by throwing overboard the malign residuum of 
dogmatism, fanaticism, and intolerance, thereby stimulating and 
nourishing a plastic vigour of intellect. His cry was ‘‘ Com- 
motion before stagnation, the leap of the torrent before the 
stillness of the swamp.” 
His successors have no longer any need to repeat those 
significant words, ‘‘ We claim and we shall wrest from theology 
the entire domain of cosmological theory.” The claim has been 
practically, though often unconsciously, conceded.- Tyndall’s 
dictum, ‘‘ Every system must be plastic to the extent that the 
growth of knowledge demands,” struck a note that was too 
often absent from the heated discussions of days that now seem 
so strangely remote. His honourable admission that, after all 
that had been achieved by the developmental theory, ‘ the 
whole process of evolution is the manifestation of a power abso- 
lutely inscrutable to the intellect of man,” shows how willingly 
he acknowledged the necessary limits of scientific inquiry. 
This reservation did not prevent him from expressing the con- 
viction forced upon him by the pressure of intellectual neces- 
sity, after exhaustive consideration of the known relations of 
living things, that matter in itself must be regarded as containing 
the promise and potency ofall terrestrial life. Bacon in his day 
said very much the same thing: ‘* He that will know the pro- 
perties and proceedings of matter should comprehend in his 
understanding the sum ofall things, which have been, which are, 
and which shall be, although no knowledge can extend so far as 
to singular and individual beings.” Tyndall’s conclusion was 
at the time thought to be based on a too insecure projec- 
tion into the unknown, and some even regarded such an expan- 
sion of the crude properties of matter as totally unwarranted. 
Yet Tyndall was certainly no materialist in the ordinary accepta- 
tion of the term. It is true his arguments, like all arguments, 
were capable of being distorted, especially when taken out of 
their context, and the address became in this way an easy prey 
for hostile criticism. The glowing rhetoric that gave charm to 
his discourse and the poetic similes that clothed the dry bones 
of his close-woven logic were attacked by a veritable broadside 
of critical artillery. At the present day these would be con- 
sidered as only appropriate artistic embellishments, so great is 
the unconscious change wrought in our surroundings. It must 
be remembered that, while Tyndall discussed the evolutionary 
problem from many points of view, he took up the position of 
a practical disciple of Nature dealing with the known experi- 
mental and observational realities of physical inquiry. Thus 
he accepted as fundamental concepts the atomic theory, to- 
gether with the capacity of the atom to be the vehicle or reposi- 
tory of energy, and the grand generalisation of the conservation of 
energy. Without the former, Tyndall doubted whether it would 
be possible to frame a theory of the material universe ; and as to 
the latter he recognised its radical significance in that the ultimate 
philosophical issues therein involved were as yet but dimly seen. 
That such generalisations are provisionally accepted does not 
mean that science is not alive to the possibility that what may 
now be regarded as fundamental may in future be superseded or 
absorbed by a wider generalisation. It is only the poverty of 
language and the necessity for compendious expression that 
oblige the man of science to resort to metaphor and to speak of 
the Laws of Nature. In reality, he does not pretend to formu- 
late any laws for Nature, since to do so would be to assume a 
knowledge of the inscrutable cause from which alone such laws 
could emanate. When he speaks of a ‘‘ law of Nature” he 
simply indicates a sequence of -events which, so far as his ex- 
perience goes, is invariable, and which therefore enables him to 
predict, to a certain extent, what will happen in given circum- 
stances. But, however seemingly bold may be the speculation 
in which he permits himself to indulge, he does not claim for his 
best hypothesis more than provisional validity. He does not 
forget that to-morrow may bring a new experience compelling 
him to recast the hypothesis of to-day. This plasticity of scien- 
tific thought, depending upon reverent recognition of the vast- 
ness of the unknown, is oddly madea matter of reproach by the 
very people who harp upon the limitations of human know- 
ledge. Yet the essential condition of progress is that we should 
generalise to the best of our ability from the experience at com- 
mand, treat our theory as provisionally true, endeavour to the 
best of our power to reconcile with it all the new facts we dis- 
cover, and abandon or modify it when it ceases to afford a co- 
herent explanation of new experience. That procedure is far 
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