Scientists do no deal in absolute truth. They seek to get closer to the truth, but acknowledge that someone may find something to contradict their current conclusion. Even if something doesn't outright contradict their conclusion, something may be found that modifies it a bit. Scientists, when pushed or being completely honest, will always say that based on all known evidence and all currently understood natural laws, this is our best conclusion. The only way someone can claim to be one hundred percent certain is if there is no possible way they can be shown something that would make them change their minds. Scientists will never assert that...creationists generally have to, because they are starting with a premise that MUST be true for their interpretation of their religion, so no matter what else may be found, it CAN'T contradict their premise, and thus must be a lie, a test, or there must be some other convoluted way for them to justify it in their mind.
A bird sort of arising spontaneously out of a chemical soup, like APhrodite out of the sea, would actually be an occurrance that would be evidence against evolution.
Abiogenesis, is in effect another type of evolution, going from obviously non-living matter, through a number of changes wherein the term living could be applied or not, depending on your definition, until we end up with something we would definitely call life. The odds of a fully functioning bird arising from a chemical soup is extremely unlikely. (Science wouldn't say impossible, but so improbable as to be indistinguishable.) First of all, it would require the extremely precise order of genetic material to spontaneously form that would code for a bird, it would need to be split into the correct number of chromosomes for a bird, it would need to find the right conditions in which to gestate without an egg...and it would have to have happened at least twice, or the Great Bird Experiment of nature's would have ended when that bird died.
The current understanding of how multi-cellular organisms arose starts with a single celled organism, in this you are right, but that single cell only has the genetic information to make more of the same cells. The next step is a colony of single celled organisms, each one living its own seperate life, but benefiting from the others around it. After a while, certain cells mutated, and this mutation had the effect of giving them some sort of ability to help the colony more, but potentially at the cost of that cell being able to live without the colony. Again, in a continuum of changes wherein it is tough to say when it stopped being a colony and started being a distinct organism, these cells kept changing and adapting, helping the group of cells survive better, thereby helping themselves survive better.
This could also be part of my confusion. I was thinking that multi-cell organisms started out as single cells with the instructions to produce different kinds of cells.
Multi-cell organisms started as colonies of single cell organisms. If you mean during gestation, then you would be right, it starts with a single cell (the fertilized egg), but in order for that single cell to grow and become the final product, as it were, it needs very specific conditions of temperature, nutrients and, perhaps most of all, it needs to be protected from being eaten by other organisms. Even if the amino acids were to spontaneously group up in a combination that would create a bird, it would need to gestate, then grow to an age where it can fend for itself, all without the benefit of an egg or any parents.
I guess what I was trying to determine is where science draws the line between possible and miracle. From the comments I would think abiogenesis is possible, single-cell to multi-cellular is possible, dinosaur to bird is possible through reproduction, but complex life from single-cell is approaching impossible in the eyes of science.
Single-cell to complex is predicted by science, not approaching impossible. If you can see that single-cell to multi-cell is possible, where does it follow that complex is impossible? Multi-cell is already more complex than single cell. Complexity is just a matter of degree, once you get the multi-celled organism, mutation, reproduction, and natural selection would begin driving more and more complexity.