The ideas put forward by creationists and believers in intelligent design are based totally on theological principals. There is no science behind it, and the pseudo-science used to support their ideas is essentially hocus-pocus. This includes their pronouncements on evolution as well as physics and cosmology. Here, I concentrate on creationism as it pertains to the physical sciences; from the history of the planet Earth to cosmology in particular. For the evolution aspect, here is a nice entry from the LabSpaces Blog about why Creationism Does Not Work. It is a good read.
The most obvious claim is the so-called "young Earth" philosophy. Believers propose that the Universe, and all it contains, was created in seven days by some sort of divine decree 6,000 years ago. This is based largely on the work of Archbishop Usher in the 17th century, which was the best chronology that could be developed at that time. It approximated to the view of the age of the Earth from Newton as well. But science has come a long way since then. All the evidence for an ancient Earth, billions of years old, is dismissed, and substituted by the idea that the Earth's geological features were formed during Noah's flood. Fossil records are dismissed as being the result of animals dying during Noah's flood, that apparently happened in 2348 BC. Really; this is what they believe and want taught in schools. Essentially, their view is that the Bible is the absolute word of God, and if science disagrees with it, then science is wrong. Interestingly, a 1957 survey by the creationists themselves to find evidence of the world-wide biblical flood fell apart when the scientists conducting it became convinced that it was false, and that geological evidence indicated a very old earth! This belief system is prevalent, in particular, in parts of the United States. Teaching this in schools means turning the US science education system into a medieval backwater!
Creationists fall into a number of other groups as well. The "Day Age" group is one example, and includes the beliefs of the Jehovah's Witnesses. They believe the sequence of events in Genesis, but interpret "days" as being very long periods of time. These are part of what is generally known as "Old Earth Creationism". Another group accepts all the scientific evidence for the age of the Universe as well as evolution, but state that this is just the mechanism used by God to create the Universe and everything in it, including life. Rather than write a whole load of stuff myself, I refer you to an excellent site that does a wonderful job of debunking creationism & intelligent design. Lenny Flank's site, though a few years old now, is a wonderful source of information. I particularly like the opening quote he has from a creationist: "We've been attacked by the intelligent, educated segment of the culture". That says it all, really.
Here is an amazing collection of falsehoods put together by creationists in Tennessee. Rep. Frank Nicely, a conservative Republican in Knoxville Tennessee, who also has interesting views on the "sport" of cock-fighting, claimed that Albert Einstein would have wanted creationism taught in public schools saying:
"I think that if there’s one thing that everyone in this room could agree on, that would be that Albert Einstein was a critical thinker. He was a scientist. I think that we probably could agree that Albert Einstein was smarter than any of our science teachers in our high schools or colleges. And Albert Einstein said that a little knowledge would turn your head toward atheism, while a broader knowledge would turn your head toward Christianity."
Oh no he didn't; this is a total fabrication by Creationists!
It is, in fact, a distortion of a quote from Francis Bacon who said, in the 16th century before there was any thought of evolution, “a little philosophy inclineth man’s mind to atheism; but depth in philosophy bringeth men’s minds about to religion.” What Einstein, who was a confirmed agnostic, actually said about his religious beliefs included the following REAL quotations:
"The word god is for me nothing more than the expression and product of human weaknesses, the Bible a collection of honorable, but still primitive legends which are nevertheless pretty childish. No interpretation no matter how subtle can (for me) change this."
"It was, of course, a lie what you read about my religious convictions, a lie which is being systematically repeated. I do not believe in a personal God and I have never denied this but have expressed it clearly. If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it."
"A knowledge of the existence of something we cannot penetrate, of the manifestations of the profoundest reason and the most radiant beauty - it is this knowledge and this emotion that constitute the truly religious attitude; in this sense, and in this alone, I am a deeply religious man."
Creationism & Intelligent Design
Pseudo-Scientific Nonsense