Since my diagnosis with bladder cancer, I have had several conversations with friends who have urged me to "think positive!" This is an admonition to which I respond generally negatively, for reasons that go back to the time when my father was dying of cancer in the mid-seventies.
In those days, there was a popular idea that there was a "cancer personality:" introverted, pessimistic. I found the idea hurtful and unscientific. Cancer, I believed, was strictly a consequence of events in the physical world. The idea of preventing or curing cancer by thinking happy thoughts was superstitious nonsense designed to blame the victim and, perhaps obscure the reponsibility of polluters who were pumping carcinogens ino the environment.
Since then, my ideas about how the mind interacts with the body have changed significantly. Since I conceive of human consciousness as a manifestation of physical events in the brain and since we know that the major function of the brain is to control the functioning of the body, it seems perfectly possible to imagine that how a person thinks and feels can effect how his body reacts to cancer or anything else. The brain is an organ of the body connected to the rest of it by nerve, blood, bone, etc. and the function of the brain effects the other organs just as their function effects the brain.
So, what bothers me now about the admonition to "think positive" is not the notion that positive thinking might help, but my inability to understand what it means for "me" to decide how I will think or feel. If my self, my ego, is, in fact, a consequence of my brain function, how can "I" cause my brain to think about things differently when "I" am, in fact, an idea or sensation produced by the material action of my brain? The causation arrow runs the wrong way. Indeed, it seems that my optimism waxes and wanes with my physical state--I think optimistic thoughts when I have had enough sleep and eaten healthy food.
So, rather than trying to fool myself into believing things that are not true, my conclusion is to try to improve my state of mind by taking care of my physical body by making decisions about what to eat, exercise, etc. Hopefully, that will produce the positive brain activity that will help me survive.