Let us in the meantime, however, consider what we have reached by the proposition above stated. What are called miracles may be divided into three classes. The first are purely spiritual, affecting mind without the intervention of matter, such as visions (though these _may_ originate in the brain, and therefore belong to the next class), gifts of tongues, inspirations, mental resolutions. The second affect mind in connection with matter, such as, perhaps, the healing of paralytic or epileptic affections, and certainly the restoration of life to the dead. The third affect matter solely; they include the healing of wounds, or of corporeal disease, such as blindness, or fever; the dividing of waters; the walking on water, or raising an iron axe-head from the bottom of water; the falling of walls or trees; the opening of prison-doors, and such like. The first two classes we may, in any discussion limited to the laws of Nature, leave out of view, because it cannot be said that we know any laws of Nature affecting mind by itself, or even mind in relation to matter. Metaphysicians have interested themselves in trying to trace the origin or sequence of intellectual processes, but I hardly think any would assert they had discovered or defined what can properly be called a law; and certainly, if any do assert it, the accuracy of the assertion is controverted by as many philosophers on the other side. Any direct influence of God on mind cannot, therefore, be charged with being in violation of natural law. Nor can it even be declared to be contrary to universal experience, since in this case the negative evidence of those who have not experienced it would only be set against the positive evidence of innumerable persons who affirm that they have experienced it.