PRESIDENT S ADDRESS —SECTION A. 39 
of any such idea as attraction or repulsion is of doubtful legiti- 
macy ; this, of course, because as an ultimate view it implies 
actio in distans. According to Sir Isaac Newton (g), “ No one 
with any competent faculty for philosophical thinking” will 
admit action at a distance as a final explanation of the reaction 
between material bodies, a very formidable dictum until other 
supposed explanations are reduced to their ultimate terms. 
Mechanical philosophers have been particularly scornful about 
this matter. On a close examination, however, of all final ex- 
planations of natural phenomena, it will be found either that 
the original conceptual difficulties have reappeared, or that 
others equally embarrassing have taken their place; and this is 
to be expected. All forms of merely mechanical interpretation 
of phenomena of which there is any historical record are on the 
horns of the same dilemma. The mechanical philosophy of 
Newton supposes that some form of impact or contact is essential 
in imparting motion. 
Energy as an Ultimate Conception.—The adoption of energy 
as an ultimate conception to erp/ain phenomena is open to 
objection, because in origin it is clearly of a derivative character, 
its generating elements being mass, space, and time; per se, it 
is wholly unintelligible. As a generalisation, a pure abstraction 
in which the mechanical elements of Nature are summed up, and 
one from which we can formally deduce the details that have 
already been implicitly or otherwise included in the generalisa- 
tion, it is admittedly of the greatest practical value. But 
generalisation and deduction d6 not constitute ultimate explana- 
tion. The conception, moreover, has not the supposed merit of 
what may be called’ picturability, which Hagenbach considered 
to be a not unimportant element of intelligibility (7). 
Conventional Restriction of the Problem of Science.— 
“ Nothing,” said Democritus, “sweet or bitter, hot or cold, or 
coloured exists, in truth there are only atoms and void” (7), 
which is really equivalent to affirming that one’s philosophy pro- 
poses to ignore those elements. To deliberately do so, with a 
view to restricting the problem of explanation within certain 
definite limits, is, of course, legitimised by the fact that we are 
overpowered even by the difficulties inherent in the relatively 
simple problem then remaining ; it is desirable to recollect, how- 
ever, that the problem solved zs a partial one only. The solu- 
tion is really of a conventional representation of reality, designed 
to cover a certain range of facts. The naivete with which diffi- 
culties have been glossed over, hidden under mathematical 
(q) Letter to Bentley. 
(hk) Zielpunkte der physikalischen Wissenschaft, p. 21. 
(z) vou yap, enc, YAuKe, Kal VOUw TLeKpOV, VOuUW BEpuoV, Vouw PuxXpdV, Vdum 
xpown. éren 5€ droua Kai xevov. Mullach I. 357. 
