This extends the billiard ball construct that is often used to characterise and demonstrate principles of physics but adds the component of irregularity (the "meaty" part is just for artistic effect). The importance of this distinction is that it describes the illusion of unpredictability, in that a regular billiard ball is said to be predictable as it travels in a way that is consistent with the direction of the initial force acting upon it, but an irregular shaped billiard ball will appear to almost have "a mind of its own" as multiple forces and impacts drive it in various directions. To illustrate this, I will appeal to my dog's favourite toy:
(For any hardcore behaviorists, I recommend you turn away now as I am about to engage in some mild anthropomorphism).
My dog loves this ball (currently sans a number of nodules that have been gnawed off) and I believe it is because, unlike a tennis ball, it will bounce in an unpredictable way when thrown. Sometimes it just bounces forwards like a tennis ball, but often it will swerve wildly to the left or right, and then bounce off in some other direction after making contact with the floor again. I can't say for sure but it seems to me that this captivates my dog as it almost mimics the unpredictability of living creatures (which, incidentally, seem to be the only other thing that can hold his attention for any extended period of time).
HUMAN NODULES
My above analogy was a rather roundabout way of trying to distinguish between true unpredictability and pseudo-unpredictability. The former refers to aspects or agents in the world which cannot be predicted due to some inherent stochastic component, whereas the latter refers to things which only appear to be unpredictable due to our ignorance of the details of the situation. In the case of the irregular-shaped billiard balls, the "unpredictability" comes about as a result of us not having direct accessibility to the variables affecting its behavior at any point in time; that is, we don't know which nodule is being acted upon, or at what angle, or with what force, and this prevents us from making simple predictions like "if I hit the ball on this angle, it will travel in this direction".
So what are these 'nodules' on humans? As you might have expected, humans have slightly more nodules than the ball my dog loves, and these nodules are composed of far more intricate substances than the rubber of the ball. They are the complex interactions between our genetics and environment, our histories and current situations, our perceptions and reality, and so on. When we are pushed by a force, we are not only behaviorally thrust in one simple direction, but instead we are essentially pushed into another force (e.g. our genetics) which pushes us into another direction that crashes into another force (e.g. our reinforcement history) which pushes into another direction again, ad infinitum.
