For the divine, earth is an illusion, heaven a reality; for the positivist, earth is a reality, and heaven an illusion.

The former in his retirement studied intensely the world that he thought real, and he could do this the better for being not distracted by the other.

The positivists imitate the divine in neglecting what they think is an illusion; but they do not attempt to imitate him in studying what they think is the reality.

The consequence is, as I have just been pointing out, that the world they live in and to which alone their system could be applicable, is a world of their own creation, and its bloodless populations are all of them _idola specus_.
If we will but think all this calmly over, and try really to sympathise with the position of these poor enthusiasts, we shall soon see their system in its true light, and shall learn at once to realise and to excuse its fatuity.

We shall see that it either has no meaning whatever, or that its meaning is one that its authors have already repudiated, and only do not recognise now, because they have so inadequately re-expressed it.