ii  i THE CADET. 53
_ sicists, or perhaps rather those among whom their views have become current,
·`  who merit the criticism. An attempt has been made to use these determinations
5.  of the physicists somewhat as a club to beat the geologists into more humble at-
  titudes. VVe voice here a protest against any such assumptions of superiority on
j _,_  the part of the physicists. They occupy no vantage ground over the geologists,
  such as Lord Salisbury in his Inaugural Address to the British Association, as-
  sumed. This claim cannot be made by the physicist either by reason of the class i
  of facts with which he deals, or by reason of his method of marshaling those facts
   ‘` and drawing conclusions. Lord Kelvin (Sir \Villiam Thompson) assumes cer-
  tain rates of earth cooling and then by exceedingly intricate mathematical pro-
;.  cesses (the accuracy of which we do not call into question), determines the time
  in the past when a solid crust must have formed tor the first time upon the
  molten interior of our planet. This he places at somewhere between 20 and 400
  millions of yea1·s ago, and concludes from this that geologic time (time since
  stratified rocks began to form) probably comes within 100,000,000 years. I
  Similarly George Darwin, estimating from the influence of tidal friction, by a
  most able course of abstruse mathematical reasoning, comes to the conclusion
ii:.  that the moon could not have separated off from the earth longer than 57,000,-
  000 years ago and hence that the earth must have been molten up to at most so
.".’ recent a date as that. Again, Prof. Tait, combining physical and astronomical
`   methods (rate of retardation, rate earth is losing heat and rate the sun is cooling
  ofl), argues that all geological work upon the surface of the earth mustbe limited
ii?  to the last 10,000,000 years. Now we do not presume to call into question the
·_;  mathematics of these calculations, what we wish to emphasize is, that the physic-
  ists and astronomers must, like the geologists start with certain physical data as
  their premises and the likelihood of these involving error is just as great in the `
  one case as the other. Simply because in their reasoning processes, the one set .
  of investigators use calculus, while the othe1·s may content themselves with i
  simple arithmetic, is no reason why 1ny special certitude attached to the conclu-
;i  sions of the former.
  It would be interesting if time permitted to discuss the question of geological i
  time in its relation to the doctrine of evolution. Much has been made of this so
i· called shortness of geological time by those to whom the revelations of biology
 r along this line are unwelcome (that is by those who would fain express prefer
i  ._ ences for what they desire to be true and what not). It is asserted with ill sup-
i`  pressed signs of gratification, that Lord Kelvin will not allow Darwin time _
·  . enough for his evolution, and the conclusion complaccntly drawn is that the
  whole theory of evolution has received its death blow at the hands of the physic-
 ii ists. Now, without stopping to consider that the very reverse of this proposition .
 i might possibly be defended with at least as much show of reason; that is to say,
  it is the speculations of the physical scientists that have met with a decided
  . Qt
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