Imagine the mind to be made up of soft matter. As each thought passes through it, an impression, like a scratch, is left on it. When similar thoughts are repeated, the small scratch deepens into a canal. Every subsequent thought has a tendency to flow through that ready-made thought canal. Thus, if the impression or the canal, was produced by good thoughts, then a good character is maintained and strengthened by the subsequent thoughts flowing irresistibly in that direction.
