Okay, I'm being serious now...
Iím a little surprised no one thought to say that disease is simply a part of life. Why does there have to be any REASON at all? Reason, that is, in the sense that it must serve as part of some ďhigher plan.Ē If there is a reason why humans or anything else contract disease, it is evolution.
Diseases result from genetic defects, environmental/dietary factors, and confrontations with other organisms (i.e., infections).
Why do people have heart attacks? Atherosclerosis most often, caused by dietary imbalances and lack of exercise.
Why do people get cancer? Genetic defects, or genetic conditions, actually, that can be neither good nor bad in and of themselves but become cancerous when triggered by other factors.
Why do people get influenza, anthrax, or small pox (putting aside the use of man-made delivery systems such as an infected blanket or the US Mail)? The disease there is a confrontation with another organism; you canít see it or hear it, but the organism is struggling for life every bit as much as any other living thing is. It can kill us or make us sick, but thatís just what they do. If a lion attacks and kills a man, we say of course, what would you expect, lions do that. It is no different with biological pathogens. Such is life.
And such is life, indeed. Everything living must die. Not for any greater spiritual cleansing, or as part of a Supreme Beingís Master Plan. If nothing ever died, our planet would be uninhabitable. There wouldnít be enough actual physical space to hold everything, and not even close to enough food or water.
Disease, like aging and accidents, is merely one of the ways that things die. And die they must. Again, I am trying to stress here the actual, practical, real-physical-world reasons why that must be so.
You can ask, but WHY does the lion do that, or the shark, or the e. coli bacteria, why? Itís merely a conflict between incompatible forms of life. Why are there incompatible forms of life? Why are there bacteria and other infectious agents in the world? For the same reason as there is any life: evolution. The process of natural selection. Microscopic organisms evolve like any other form of life, indeed, they do it much faster, and have stayed one step ahead of the more highly developed life forms through sheer speed of reproduction.
Why are there genetic ďdefectsĒ? Some times, itís not really a defect. Iíve read that people with two sickle cell genes can suffer gruesome deaths, but one gene is also quite effective in warding off malaria. Similarly, the genes responsible for cystic fibrosis help the human body defend against typhoid fever. Studies have shown that breast cancer is much more prevalent in developed societies, where women also typically have many, many times the number of menstrual cycles during a lifetime than women in less developed societies (itís tempting to take up hunting and gathering in Africa, believe me); it is a gross oversimplification to say menstrual cycles, and all the hormones associated with it (and the absence of other, beneficial stuff going on in a womanís body during a pregnancy), simply wear the body down, but thatís essentially where the research is headed (as I understand it). The human body evolves over a loooong period of time, and our lifestyles have outstripped our ability to handle things in some cases.
Why does the human body crave so many things to eat that are bad for us and give us heart attacks? Evolution again, of course. Our earliest ancestors (and Iím NOT talking about Adam and Eve here... more like Lucy) who craved and found fatty foods were more likely to survive famine than their thinner relatives, therefore they had more opportunities to reproduce, and over the course of millions and millions of years we have today, homo sapiens sapiens, a species that loves fatty foods. None of this was a problem, really, in hunting and gathering societies where fatty stuff is hard to come by. It is a problem today, in a world of McDonalds and Burger King, and Ė surprise Ė heart attacks are now much, much more prevalent. Evolution and biology Ė not spiritual cleansing.
Now, maybe evolution itself is but a case for the wonder of Godís plan, how marvelous it is, how He thought of everything. But in the end, THAT is but a question of faith Ė you either believe it or ya donít Ė and it is no better than my giant tortoise nonsense above. Our understanding of how evolution works may be imperfect (my understanding certainly is, I am not a science-y kind of girl), but it has the merit, of course, of actually being based on logic, on things that can actually be identified in the actual, physical world. It may be disturbing to think that disease or even life itself is random, it happens without reference to a Plan. So be it. Thatís life for ya.
Believe it or not, lol.