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is usually unprofitable from the same cause. It becomes, therefore, 
largely a matter of personal opinion as to what quantity of facts should 
be available before a generalisation is formed. Some would insist 
that no generalisations should be indulged in until all the facts are at 
our disposal. This appears to me to suggest a finality of knowledge 
that is impossible, and to put off the explanation of facts for ever, in 
other words, to rule the subject out of consideration. At the other 
extreme are those who think that a few facts, carefully co-ordinated, 
form often sufficient ground to generalise upon, recognising, of 
course, that the theory adduced must be in accordance with the facts, 
and that, if additional facts show the theory to be untenable, it must 
be at once rejected and a new one formulated. “We do not make 
progress,” Weismann asserts, “ by blind experiment, but only by 
experiment having a purpose in view ; and for this we require an 
interpretation of the immediate facts.” I quite agree with this view 
of the necessity of an immediate explanation, even if, later on, new 
facts necessitate its alteration or modification. 
One sees, of course, there must be a vast accumulation of what 
Dr. Hicks has described as “ wreckage ” floating about every theory 
of importance which has been formulated. The deduction of the 
cause of any phenomenon based upon the facts which come within the 
range of of our senses, is a slow and laborious process. It is only by 
the rejection of theories found to be untenable by fresh accumulations 
of facts—that is, by the manufacture of such wreckage—that a theory 
nearer to the truth can be formulated, and advance can be chronicled ; 
but, because of this, are we to fear to produce the wreckage, and 
allow our science to become stagnant for want of energy to carry it 
forward ? 
There are those who consider that true science only begins when an 
attempt is made to draw conclusions from facts, and would rule the 
mere accumulation of facts out of the definition. Professor Meldola, 
in his address to the Fellows of the Entomological Society, in January 
last, said :—“ All science necessarily begins with observation or 
experiment, i.e., with ascertained facts, and it is, perhaps, unnecessary 
to assert that no mere collection of facts can constitute a science. We 
begin to be scientific when we compare and co-ordinate our facts with 
a view to arriving at generalisations on which to base hypotheses, or 
to make guesses at the principles underlying the facts. Having 
formed the hypothesis, we then proceed to test its accuracy by seeing 
how far it enables us to explain or to discover new facts, and, if it fails 
to do this to our satisfaction, we conclude that our guess has been a bad 
one, and requires modification or replacing by a better one, that is, by 
one more in harmony with the facts.” 
This brings me to another important point, viz., the process of 
theorising, or rather of hap-hazard guessing indulged in by irresponsible 
and uninformed individuals, and when one comes across a more than 
usually conspicuous example of this kind, one is almost unconsciously 
reminded of the second of the two objections formulated by Elwes, in 
his Presidential Address to the Fellows of the Entomological Society, 
1894, against entomological speculations. The first was, that “ tho 
knowledge we have of the actual facts is, in many cases, quite 
insufficient to bring such speculations to a definite end.” Tho second 
