Force:
In Physics, Force is define to be the agent that causes a body to change its state of motion.

A body changes its state of motion if it is:

1. at rest and begins to move.
2. moving and changes its speed.
3. moving and changes its direction of movement.

Force is the source of all motion, or more precisely, the source of any change in an object's motion.

We say that a force has acted on a body if the body changes its state of motion in any way. This statement is the inverse of Newton's First Law.

Force is a man-made concept created by Newton to explain the source of a body's motion. Newton's Second Law is better viewed as the definition of Force, rather than a true law of Nature. The utility of such a concept is that it produces a model which can be used to explain and predict the motion of objects.

Do forces exist ? I do not know, but I do know that it is a useful concept that brings meaning and order to the motion and interaction of bodies.