2 
Presidential Address. 
But if the essential idea of this principle is indeed so simple, wherein, 
it may be asked, does its importance lie? The great value of the belief 
that similar effects always follow similar causes lies in the fact that we are 
thus stimulated to endeavour to understand what has taken place in the past, 
and that the knowledge thus acquired gives us some power of looking into 
the future. Daily forecasts of the weather are now issued, and these 
forecasts will obviously become more and more trustworthy as our knowledge 
of the natural laws affecting the air and the skies become more and more 
perfect. If we had remained faithful to the creed of the savage as to the 
incalculable nature of storms, we should now have no faith in these fore¬ 
casts ; or, in other words, without a belief in evolution, meteorologists 
would never have been stimulated to make those scientific researches which 
have already so greatly increased our prophetic powers. And our present 
scientific creed is unquestionably acting in a similar way as regards the study 
of man and his social progress. Indeed it now seems obvious that in a 
changing world our powers of foretelling the future—that is of making 
any forecast concerning the results of the forces now at work—must entirely 
depend on our knowledge of the sequence of events in the past. It is for 
this reason that we are attaching greater and greater importance to the 
situdy of the natural laws regu^latihg the sequence of human events; for 
without any such knowledge we should in this world be marching blind¬ 
fold into an unknown future. And it will in time be recognised that it 
is by increasing our prophetic powers that a belief in evolution has conferred 
its greatest benefits on mankind. 
In order to make our knowledge of the evolutionary process practically 
useful, it is, therefore, obviousHy of the first importance that we should 
know how and why succeeding generations of mankind have resembled or 
differed from each other. The questions thus suggested for consideration 
may be divided under two main headings. In the 'first place it is to be 
noted that individually we pass on our learning and our thoughts to our 
juniors and our successors by writing and by word of mouth, whilst the 
material wealth of the nation in the form of improved surroundings is 
in a perpetual state of transference as time goes on. In other words 
the environment of one generation is very largely dependent on the environ¬ 
ment of the generations which preceeded it; and according as we are 
increasing or dissipating the mass of accumulated knowledge, as we are 
careful or careless in the expression of our thoughts, as we add to or 
diminish the wealth of the nation, so is our conduct tending to make the 
world progressive or retrograde in this respect. No one can deny the 
importance of external conditions to the morals, health and comfort of 
mankind; and our instincts, selfish and unselfish, may be trusted to 
ensure a large amount of attention being alv^ays devoted to the factor of 
environment in the evolutionary process.