Is it possible to truly understand all the evidence for evoltuion and claim it is false??
What is the evidence for creationism? What is the evidence which disproves evolution? Is it possible to reject 150 years of scientific research?
I am sure that half of them may possess the intelligence to at least get the gist of it. However, they are too narrow-minded to open themselves to the possibility. This is sad because the study of evolution gives us such rich insight as to the power of human nature. It even gives credibility to the possibility of an Intelligence much more powerful than our own as the hidden hand behind the miracle of genetics. However, how can you appreciate your nature as a human when you feel you are a product of a fake Adam and Eve?
However, to answer your question, yes, creationists may be able to understand the process and theory of evolution. Yet, they do the worst thing a human being can do to himself: Deny themselves the opportunity to get to know more about it, and limit themselves to a book written years after Jesus had already been dead and gone.
Understanding and belief are two different things. I think many creationists understand the theory itself just fine, while many others have decided what they believe without knowing what they are arguing against. So we can't generalize about what all creationists understand, just as we can't generalize about what they all believe. It is a diverse group theologically and philosophically.
There are some devout fundamentalists who do, indeed, understand the theory of evolution. But their religious beliefs run counter to this theory, and so they reject it. They believe what they have been taught in their churches and what they have grown up with in their religious culture because their faith is stronger that any evidence to the contrary. The Scopes Trial concerned this conflict of science with faith.
You may wish to watch the old movie, "Inherit the Wind" based upon the Scopes Trial of 1925 in which Clarence Darrow debated William Jennings Bryan.
There are lots of sites that lay out the evidence for creationism in detail. Here's one of them:
What you have to remember is that creationsist believe that the Bible is the literal word of God. If you start from that point, you have to reject the science. You have to figure that the scientists have made mistakes. Scientists regularly reject evidence that does not fit with their paradigms -- they explain it away. Creationists do the same thing.
So creationists would say that they have an alternative explanation and many of them would say that their side is right on the science.
Do creationists understand evolution??? Of course they bloody don't!! In an often repeated survey, American adults are asked the following question...
How long does it take the earth to complete one orbit of the Sun?
Approx 50% of American adults cannot answer this rookie science question correctly. that's... FIFTY PERCENT! Half the nation! And you ask if they clearly understand evolution? Ha! They can tell you who played defense for the Dolphins in 1978 or what color shoes Oprah likes, but Evolution?...
Let's put it this way... A significant percent of Americans are so ignorant of this subject that they are ignorant of their ignorance.
It is a perfectly simple statement: if you think you can disagree with the fundamentals of evolution, then you don't understand it. There really are no grey areas on this. For 150 years, evolution has been the driving force for biology, it has become so powerfully developed as a theory and an effective scientific tool that only ignorance would dare to doubt evolution was wrong. There may be grey-areas concerning the fine-tuning and the specific lineages, but as a model for our origin it is a certainty.
And the arguments offered by creationist speakers to 'disprove' evolution are, frankly, pathetically weak. Those people who publicly attack evolution use arguments that either
a) Prove they don't know anything about evolution
b) Prove they know their fleece-able creationist followers don't know anything about evolution and will trust their lies and hucksterism.
If you understand evolution (especially how it relates to the evidence found in genetics) then you can't pretend that animals didn't evolve. You can't. And to do so in public is like shouting, 'I'm ignorant and uneducated for Jesus.' Or like shouting, 'I'm an evil charlatan who's happy to lie to stupid people for money.'
No-one credible challenges the basic facts about evolution. Because they are provably true. There is no controversy.
(this link is part 1 of the famous Youtube series, "Why Do People Laugh At Creationists?", made by a research physics professor, it is highly entertaining and educational.)