If I find a chipped stone how can I determine whether it is the result of deliberate action of an intelligent being or the result of last year's spring flood, mere chance?
Actually two questions: At what level of chipping done on the stone could I say with a certainty of mind that only an intelligent agent acting with deliberation could produce it?
First, it's probably not how chipped the stone is which is important, but how unlikely the pattern of chipping is.
For example, 8 chips in a perfect circle on a flat stone could be far better evidence of an intelligent chipper then a huge stone chipped away by a hundred million randomly executed chips.
So the two extremes (see picture above) are easy -- if it's purely random looking, then it probably was caused by natural process. If, on the other hand, it has features which are highly unlikely to have happened by random or natural process, then we'll really want to consider that it probably had a designer with a plan.
Now the dividing mark between intelligently designed and naturally chipped into shape can be a little tricky. And this is not because natural process is just one end of a continuum with intelligent chippers on the other end, but rather because obviously an intelligent chipper can observe then replicate a natural shape. And also because many times the artifacts we get are a joint project between two completely different forces - first an intelligent chipper then erosion. For example, the above rock could be either natural or man chipped, and it is sort of hard to tell. Furthermore, if it was man-chipped, but later had the tip broken off by natural process, it'd be even harder to tell. So for some things right on the border it is hard to tell whether they were natural or intelligently chipped.
But it is vital to remember two things: Just because something has some signs of random wear and tear it doesn't mean that it wasn't a design before that, and secondly, and most important:
The fact that some things are hard to tell whether they were natural or intelligently chipped does not invalidate those artifacts which are clearly intelligently chipped!
Some things in nature do naturally appear designed, like crystals of quartz and snowflakes, and marbles laying on the smooth ground. But you see these things are all in their most likely, lowest-energy, resting position. It may look like marbles all on a plane, evenly spaced (touching) is design, but it's just the way the marbles fall. Snowflakes certainly look designed, but they are in the order they are because, like the marbles, there is a certain way that frozen water molecules fit together more easily, so when they come to rest in their easiest position, they look pretty -- just like the honeycomb pattern that marbles give. Quarts crystals of course have their specific shape tendencies for the same reason snowflakes do theirs.
May I say to you that a living cell, which is far from its natural resting state, is an amazing evidence for intelligent design. Like the Petra stone carvings pictured above, the chances of all the parts of the first cell actually happening by chance are well proved to be unlikely by the constant and futile efforts to produce life in the lab. (I'm talking about real life, self replicating metabolizing life, with DNA.!) If it weren't so, the millions of canned foods on shelves would be springing forth in new heretofore non-existing life forms!
The reason that the cell is so unlikely is because it would require at least thousands of atoms and molecules all being arranged in a way which was not their natural or lowest energy resting state. As soon as a cell dies, all of its chemicals begin moving towards their natural resting state - in other words, the cell breaks down! I've actually watched a cell break down on my video microscope when it dies. (I shone UV lamp on it.) It was a cluster, and it instantly stopped moving and all the members of the colony just drifted away from each other.
Remember, the first cell would not only have to have the complexity of a machine that could replicate itself, but also the complex mechanism to feed itself! Being only able to replicate itself OR feed itself is no use!
Ladies and Gentlemen, we no longer believe that dirty rags spawn mice or rotting meat flies.
Thanks,
-Jesse