There is only one physical world, but unfortunately, we all live in different worlds created by our minds.

The physical world, which is separate from us, can be contacted only through our senses – sight, hearing, smell, touch and taste – but all of these are limited. There are parts of the spectrum we can't see, sounds we can't hear. We are lucky that our olfactory nerves are limited, because I suspect that the world our dogs smell is a pretty stinky place.

Furthermore, the part of the Earth we actually occupy is for most of us quite limited. We fill in the blanks with ideas and concepts and images that may or may not conform to reality. Even though we can learn from reading and hearing, the most vivid learning always comes from experience. People who have had direct contact with racism or anti-Semitism are not likely to be convinced by arguments. Reading about, say, China is no substitute for actually being there.

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Thus, the world we inhabit is shaped by our experiences. I was born in the Deep South. I would see the world differently if I had been born in New England. I've often wished we could have many lives, because I would like to experience what it's like to be a New Englander, a Midwesterner, a Westerner, a farmer, a scientist and dozens of other interesting lives. Unfortunately, in this cosmic card game we are dealt only one hand.

But since our means of learning are limited so that we can never learn everything about anything, we should avoid being dogmatic. I don't mean living in a constant state of uncertainty, but we should at least always concede the possibility that what we think is so isn't so. I have trouble understanding people who get emotionally upset when they bump into an opinion they disagree with. I've always found that conversation with people with whom I disagree is more interesting than a conversation with people who agree with me.

Perfectionism is another pitfall that should be avoided. Perfectionists are apt to be chronically frustrated, since neither the world nor the people in it are perfect. It's better to expect too little and be pleasantly surprised on occasion than to expect too much and always be disappointed.

One of the more difficult things to avoid is bitterness. In a normal life there will be disappointments, in ourselves if in nothing else. Things don't always turn out the way we want them. People don't always live up to our expectations. People we want to win sometimes lose and vice versa. The thing to remember is that from the day of our birth to the day of our death, we live only in the present. The past is only a memory. The future never exists. So the old saying that any day above ground is a good start is not a bad philosophy to follow. It's a very good idea to let go of the past and to live in the present moment. That's not easy to do, but it is a worthy goal.

There is a lot of emphasis today on cleaning up the physical environment, but the environment that should receive the top priority is our mental environment. People can quite literally think themselves into madness. Some good advice came from St. Paul when he wrote, "Whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things." That's because another biblical saying is quite true: "As a man thinketh, so is he."

Speaking of thinking, there is no good in wallowing in evil, which, by the way, Hollywood seems to desire for us to do. I'm rather tired of stories about crooks stealing from crooks and of psychopaths killing other psychopaths.