To presuppose is to make an assumption ahead of time, and then to work within that assumption. Presuppositions eventually work at a subconscious level, coloring every observation and decision.
Uniformitarianism is one of the chief presuppositions of evolutionists. It assume that all things now continue as they always have. Uniformitarianism assumes that there was no flood and there was no creation. Using this presupposition, a few of the indicators of the earth's age can be made to show a very old earth. Unfortunately for evolutionism, the vast majority of indicators show a very young earth. That's when evolutionists must use the tool of selective presentation of incomplete information. (see videos below)
Two other presuppositions are Naturalism and materialism. They say that there is no God and there are no spirits. They are presupposed and cannot stand if challenged. They are simply fabrications.
Hidden presuppositions are the most effective for fooling people. Presuppositions that are never really mentioned but treated as if they were obvious are hard to detect. Statements that begin, "Millions of years ago..." are actually magic tricks that some people can see through and others cannot. An evolutionist may start a sentence with, "As man evolved..." and most people don't even realize that the evolutionist has powerfully presupposed the notion that a scientific impossibility occurred, secretly presupposing that man evolved.
