"A simple statement that you do indeed now understand that mutations can be beneficial regardless of environment will be enough to demonstrate that it is worth continuing."
No, we never discussed that as far as I can remember. But I can assume it for the sake of argument so you can make your point.
"Certainly you must retract the statement that we already agreed that they cannot be universally beneficial - that certainly hasn't happened."
I don't understand what you mean by "universally beneficial."
"I can't see it being possible to put any organism into an environment where cancer is beneficial, can you? This is an interesting point. Because cancer is a direct result of an organisms ability to evolve."
By "evolve here do you just mean "mutate"? Otherwise it sounds like you're begging the question.
"The best fitness test going is the ability to adapt to a new environment. The way in which our genetic code does this is to introduce errors at certain rate."
You sound like you are introducing teleology here. The organism is not TRYING to adapt. It either is adapted or it isn't. It doesn't mutate so that it can evolve. It just mutates. Those mutations either help it to survive and leave more offspring or it dies. Don't go adding purpose in on me where none exists.
"So our ability to evolve is directly linked to our suffering from cancer. From that point of view cancer is and always has been beneficial in our current and past environments."
So now even cancer is somehow a beneficial mutation? Don't you think that is really grasping at straws? Don't you think if they really had any sold evidence they wouldn't need to use all these bad examples like eyeless fish, wingless beetles, sickle-cell anemia - and now cancer? I don't think I have enough faith to believe what it seems like you're claiming. Surely you must see how ridiculous it sounds.
"Yes I think this is true. I also think that the presence of proteins in mice that are directly homologous to human proteins indicate that mice and humans have a common ancestor."
Does the bill on a duck-billed platypus indicate to you that it shares a common ancestor with ducks? I bet they have some similar genes. The genes for the bill on the platypus would be homologous to the genes for the bill on the duck. The more parts a creatures shares with another creature, the more DNA it will have in common. This is evidence for design, not common ancestry. Are you able to see how I'm seeing it?
I'm loving this exchange by the way. :^)