The supernatural is being swept out of the universe in the flood of new knowledge of what is natural. It will soon be as impossible for an intelligent, educated man or woman to believe in a god as it is now to believe that earth is flat, that flies can be spontaneously generated, that disease is a divine punishment, or that death is always due to witchcraft.

I am not afraid of the priests in the long-run. Scientific method is the white ant which will slowly but surely destroy their fortifications. And the importance of scientific method in modern practical life--always growing and increasing--is the guarantee for the gradual emancipation of the ignorant upper and lower classes, the former of whom especially are the strength of the priests.

Genius, as an explosive power, beats gunpowder hollow.

Whatever part of the animal fabric whatever series of muscles, whatever viscera might be selected for comparison the result would be the same the lower Apes and the Gorilla would differ more than the Gorilla and the Man.

From the dawn of exact knowledge to the present day, observation, experiment, and speculation have gone hand in hand; and, whenever science has halted or strayed from the right path, it has been, either because its votaries have been content with mere unverified or unverifiable speculation (and this is the commonest case, because observation and experiment are hard work, while speculation is amusing); or it has been, because the accumulation of details of observation has for a time excluded speculation.

I have endeavoured to show that no absolute structural line of demarcation, wider than that between the animals which immediately succeed us in the scale, can be drawn between the animal world and ourselves; and I may add the expression of my belief that the attempt to draw a physical distinction is equally futile, and that even the highest faculties of feeling and of intellect begin to germinate in lower forms of life.

If there is anything in the world which I do firmly believe in, it is the universal validity of the law of causation.