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Proceedings of the Royal Society 
cohesive power of the target or the onward force of the ball is 
greater. If the latter preponderates, then the force necessarily 
carries the ball with it through the iron plate, with violent disrup- 
tion of its parts. 
On the same principle, it is not the movement of the molecules 
which, hitting the retina and auditory nerve, affects the mind 
with the sensations of light and sound, it is the force which they 
carry which accomplishes this. 
Though force is the operative principle in all physical "and 
mental action, yet mark the result were force not regulated, and 
bound up in connection with physical bodies. Were force freed 
from this connection, it would attain immediate equilibrium, and 
the physical universe would instantly cease to exist — action and 
reaction, momentum and inertia, resistance and localised force 
being at an end, physical law and the physical world would be at 
end with them — for the physical world consists but of the antagon- 
ism of contending forces. 
Mr Wyld concluded by referring to the distinctive nature of our 
perception of the primary or solid resisting properties of physical 
objects, and of our other perceptions. In our sensations of light 
and sound, taste, smell, and touch, the mind is passive. But our 
perception of the primary properties of external nature depends 
entirely on another principle, namely, on our consciousness that the 
mind possesses, and exerts a command over active physical power, 
or the power of animal motion. When we are conscious of possess- 
ing this power, and perceive that the Will which exerts and directs 
it, is thwarted by our coming into visible contact with outer objects, 
we discover at once that these objects possess resisting power, 
seeing that they counteract at once our power, and our Will, and 
our motion. 
This distinction between passive sensations and the exercise of 
our active mental and animal powers has not been sufficiently 
urged in refutation of Berkeley’s Idealism. The vast majority of 
realists in philosophy succumb under the apparent force of the 
absurd argument, that all our perceptions are resolvable into mental 
sensations, and therefore that our belief of an outer world hangs on 
faith alone. Mr Wyld maintains, on the contrary, that according 
to the principles of his theory we have a ready and complete con- 
