If you notice the New York Martial Arts Academy emblem, in the corners of the triangles there is an "M", an "B", and a "S".
The "M" stands for Mind. Which in Jeet Kune Do is extremely important, in the fact that it is a thinking man's art. There are a lot of subtleties in this art which force you to think and analyze. In this aspect, a strong mind is a very important asset to have.
The "B" stands for Body. This facet is obvious in its importance. The body has to be strong and fit in order to able to perform in Jeet Kune Do. We must also make sure to take care of our bodies by not filling it with toxins which will hinder it from reaching its maximum potential.
And lastly, the "S" stands for spirit. It is important for a martial artist to have a good spirit. By this we mean, that we as martial artists have to do the right thing when the choice is given to us. I.E. we must have a good heart and always help out those people less fortunate than ourselves.
In the emblem, Spirit is the only thing that is held above the art. JKD in the middle, Spirit on top, and Mind and Body at the base of the triangle.