William T. Powers
1. The Dilemmas of Behaviorism 1
2. Models and Generalizations 10
3. Premises 19
4. Feedback and Behavior 41
5. The Control-system Unit of Organization 57
6. A Hierarchy of Control Systems 70
7. First-order Control Systems: Intensity Control 82
8. Second-order Control Systems: Sensation Control or Vector Control 99
9. Third-order Control Systems: Configuration Control 115
10. Fourth-order Control Systems: Control of Transitions 129
11. Fifth-order Control Systems: Control of Sequence 137
12. The Brain's Model 147
13. Higher Levels 154
14. Learning 177
15. Memory 205
16. Experimental Methods 231
17. Conflict and Control 250
Appendix: Control System Operation and Stability 273
This book represents, I hope, a step on the path back to a concept of man as autonomous, and away from the concept of man as automaton. Yet in allowing my humanistic bias to hold sway, I do not think I have denied science. Indeed, to most readers the first part of this book will seem a direct denial of my hope, for it gives a deliberately and specifically mechanistic picture of how the central nervous system behaves.
Only after the mechanistic model is thoroughly understood will the reader see that it leads beyond ordinary mechanism and that it is capable of describing the interface between what we can represent as mechanism and what we cannot yet represent at all, but only experience.
The traditional arguments between mechanists and humanists are represented by the dispute over purposiveness in behavior. The mechanists have argued that since organisms are made of matter, they are subject to the same determinism as any physical system, living or not, and in particular are bound by the cause-effect laws governing the behavior of matter. Hence we have _behaviorism_, which treats input as cause and output as effect and all that lies between as an automatic machine having properties but no purposes. The humanists have denied this picture on intuitive and subjective grounds, claiming that no machine can experience its inputs as well as respond to them, or conceptualize its own existence, or see the need for building a machine.
This book presents an approach which may bring together these apparently irreconcilable points of view. The conclusion we are led to by the thinking in this book is that there is mechanism in behavior--but it is not the mechanism the behaviorists have in mind, for it is capable of having inner purposes in the full humanistic sense. On the other hand we are led also to seek not just a model of behavioral mechanisms, but a deep awareness that we are constructing a model; and we are encouraged to apply the model to ourselves. This process puts experience before theory but paradoxically shows that much which seems uniquely human is after all only acquired mechanism. The human remainder, the factor distinguishing man from animal or machine, is visible in the model only as a ghost, through its transcendant effects on the model itself.
Is that the Soul of which I speak? The Atman? The Awareness? Of course it is. It is myself, yourself. But I have not been forced by this theory to conclude that this factor, this self, has to be treated either with tact or with reverence. It is a perfectly natural part of the totality we call a human being. It has functions in this otherwise mechanistically representable structure, and is not just along for the ride. Animals may have it, too. If it does not seem subject to the laws of physics, I take that as evidence that physics is still in an early stage of development. Whatever its nature, and I am sure it has a nature, it is adequately understandable through its effects on experience--and, incidentally, on learning. Adequately, that is, for any purpose I can now conceive.
Scientists who view progress as a series of narrow escapes from metaphysical traps may find this book tough going in places, especially those places where I cheerfully give in to the temptation to anthropomorphize. It is precisely that kind of scientist who has the most to gain by understanding this book. If I anthropomorphize, be assured that I have done so with reasonable care and for a purpose. It is necessary, in order to understand the organization of human behavior, to recognize that one is constrained by any property he would impose on his experimental subjects if they too are human. What is necessary is not to avoid attributing human properties to human beings, but to avoid attributing such properties arbitrarily. There is at least one method, which is fully described later in the book, for testing the appropriateness of anthropomorphisms.
It is a long way through this book, both in words and in new concepts. To save the reader a long wait for what will never appear, I should state now that the theory nowhere predicts how a particular person will react to a particular event. I have not been concerned with the kind of theory which predicts that event A will probably lead to behavior B. To me such theories are not theories at all, but summaries of observations. They in no way answer the questions I have been interested in, such as the question of what kind of organization is required to permit a person to reproduce in present time an experience contained in his present-time memories of the past. Not a particular experience--any experience.
In that same vein, I have not been concerned with relating behavior to antecedent events. Rather, the central problem has been to find a plausible model which can behave at all. This has required a long effort to penetrate beneath surface descriptions to see what is being taken for granted. For example, it will be shown later that the brain does not command the muscles to act. That concept implies properties which the neuromuscular system simply does not have. It ignores the fact that we move about balanced on jointed sticks supported only by flabby rubber bands of variable tension. There is just no way the brain can select a muscle tension that will produce one and only one behavioral effect, even if that tension is accurately produced.
The result of this approach is a model nearly devoid of specific behavioral content. I once felt that it was my duty to supply the model with content as well as form, but I am wiser now, and much more impressed with my ignorance. What is up to me is in this book. What I do best is in this book. Others who know more about behavior and many other subjects are the ones to put the content in. Where I have tried to make the form more comprehensible by suggesting content I have stepped over the bounds of my knowledge and have probably made mistakes. I trust that they can be corrected without obscuring what is most important about this model--and that is this: Behavior is the process by which organisms control their input sensory data. For human beings, behavior is the control of perception. That is what is important about the model--that, and all that is implied by it.
William T. Powers 1973