INVENTION
The following chapter is given in its original form as a lecture to the Engineering Society of the Stevens Institute of Technology.
Its value in furnishing a side-light on the subject of habit, to which the preceding chapters have been more directly applicable, lies in its emphasis on the importance of the inventor (or designer, if you prefer) having clearly before him at all times the effect of habits of thought and action both in himself and in all others. These modes must be both conserved and combated in himself when building up favorable mental state. He must build on habit in order to have his mind continue in its application to a chosen subject, and he must combat any tendency to follow habit lines of thought that may have been established by observation of the older forms or methods. His inventions must be of a kind that will be readily made, sold, and used by men whose habits of thought and action he cannot readily change.
This should be of value not only to the designer, but also to those who direct or co-operate with him.
In designing the parts of a machine, the need of trimming here and there, of giving up this or that ideal form just to get things together, must be seen and done unflinchingly. And in the same way the whole scheme must be made to conform to the economic conditions.
If the machine under consideration is like a machine tool, and is to be offered for sale, then the manufacturing, selling, and use must be taken into account. In machine-tool design a wholly new invention is an exceedingly rare thing, and a successful new machine is still more rare.
We must remember our own tendency to follow precedent, and we must make an effort to see the problem in its natural form without being misled by the solutions evolved by others.