Alan,
As DW said, you make some very valid points. Points that I believe should be, and must be, addressed by Christians today if we hope to reach the hearts of all people, including all educated people, with the message of Christ.
Let me say to begin with that I accept the clear testimony of the fossil record just as you have presented it. I believe you have painted a picture of the history of life on earth that is both fair and accurate. As you may know, I believe God used evolution to create all life on earth. And I believe that all life forms on earth evolved in exactly the way God desired and directed them to do so.
You wrote: If, as various Christians claim, the Bible indicates that disease only came into the world after Adam's sin, then the Bible is obviously out to lunch.
As you probably know, the Christians you refer to base their claim largely on their interpretation of one Bible verse, Romans 5:12. There we read, "Sin entered the world through one man, and death through sin, and in this way death came to all men, because all sinned." Most so-called "fundamentalist" Christians claim that this verse teaches us that death did not exist anywhere on earth, even among animals, until after Adam sinned. Then, they tell us, as a direct result of Adam's sin, death and the diseases which bring about death came to all creatures on earth, animals and humans, for the first time.
But is that really what this verse says? No, it is not. It says that because of sin, "death came to all MEN." It says absolutely nothing about the deaths of animals. I hope we don't here have to discuss "what various Christians claim" the Bible teaches. I hope we can agree that, at least in this area, it is their interpretation of the Bible that is "obviously out to lunch," and not the Bible itself. I assume we can agree on that point. For I have no desire or intention to defend any of the nutty interpretations of the Bible promoted by "fundamentalist" Christians.
After describing very well the "red in tooth and claw" nature of the history of animal life on earth, you asked, "What sort of God would create such a kingdom of life?" I found that to be a very good question. You answered your own question by saying, "Obviously one that didn't care much about pain and suffering on the part of his creation." The answer you gave certainly seems to be a logical one. But just because it seems to be a logical answer does not mean it is the right answer. For, as we all know, things are not always what they seem to be.
The problem I have, as a Christian, in providing you with another answer to your question is that any answer I give to you will amount to little more than my "educated guess." As a Christian, I would like to answer your question by saying, "Well, the Bible says this about that." But, unfortunately, as I am sure you know, the Bible says almost nothing about why God chose to create an animal kingdom which is now filled with much violence and was even more violent in the past.
As I said earlier, I am a Christian who believes that God used evolution as His means of creating all life on earth. I also believe that the Genesis account of creation not only allows for Christians to understand that God created all life in this way but actually strongly implies that He did so. For instance, in Genesis chapter one, verses 12 and 24, we are not told that God directly created "vegetation" and "living creatures," but that "the land produced" them. However, Genesis says nothing about why God chose to create our world in the way that He did. It only tells us, in a very brief way, what He did. It says very little about how He did things. And nothing at all about why He did things in the way that He did.
I long ago asked myself, "From what I know about the God of the Bible, why would He have chosen to create all life on earth, including the human race in this way? Why would He have begun life on earth in an extremely simple way and caused earth's life forms to eventually become much more complex? Why would God have desired that the first organisms on earth possessed very little intelligence and then, later on, caused the land to produce creatures with progressively greater intellectual capacity? Why would God have wanted earth's earliest creatures to have been, for the most part, both extremely violent and highly predatory toward their fellow creatures? Why would God have created the human race, with our great capacity for love, kindness, mercy, gentleness and compassion toward our fellow humans and even toward lower life forms, to appear on earth long after He caused life forms lacking such "higher" qualities to appear on earth? And why would he have caused the human race to actually ascend from lower life forms which lacked such higher qualities?
I believe God may have done so to illustrate some very important lessons. Lessons such as these: Having ascended from lower life forms, human beings should now behave in a way that is far removed from the behavior of animals. The violence and predatory behavior that so filled earth's past, and still largely fills the animal kingdom, should be looked upon as behavior which is now totally inappropriate for our present and our future. By knowing our past and our planet's past, we know where God has brought us from and in what direction He now wants us to go. The Bible indicates that God is now willing to forgive all of our past lives, animalistic as they were, if we will strive to leave them behind. The Bible also tells us that if we will do this, God will bring about in each of us the final step in mankind's evolutionary process. He will do so by miraculously changing us into incorruptible, immortal, sons of God. I think it was probably for reasons such as these that God chose to give the human race an extremely animalistic prehistory.
In any case, I do not believe that we are justified in doubting the goodness of God simply because the history of animal life on earth has long been "red in tooth and claw."