What kind of scientific experiment would you do to determine if something were created by intelligence or formed through natural processes? Would testing something chemically prove it was designed? Only if you knew that the chemicals were unable to produce that combination or arrangement without intelligence. So you would set up experiments to test the natural properties of the chemicals involved, and when you were sure that the chemicals could not produce the chemical structure or arrangement you could determine with some certainty that it was intelligently designed, rather than naturally formed.
Using the scientific method you can determine all the ingredients in a jar of peanut butter, but what science cannot do is repeat the process that produced the recipe, that's a part of history. Using science you could make your own recipe that produced a similar jar of peanut butter, but that would be intelligent design. The problem with searching for natural origins of life is that experiments must be intelligently designed to produce desired results when attempting to look for natural origins. Not recognizing this causes misinterpretations of the results.
In order to study the creation of something, you need to be there at the creation event.
You need to observe the steps. Yet that would only be the start. In order to understand the process, you would have to repeat the steps yourself. The problem with studying life's origins is that the creation event or events are part of history. They can't be examined by observing the process. One of the biggest mistakes modern science has made is to try to reconstruct history using science alone. But it can't be done. Since science cannot examine historical events, fictional stories are created about what they think happened. When you use science to tell a fictional story its called science fiction.
Science is limited to the present, and to the material world; science can only help confirm past events, but it cannot prove them. We cannot know who really shot JFK apart from history, or who wrote Shakespeare. We only know Newton's and Einstein's discoveries were valid because they can be tested fully today. We cannot reproduce the event that created the first living cell, but we can examine the processes within a living cell today. We cannot reproduce the events that created man, but we can examine biological changes today. But if the creation of man was not an evolutionary biological event, science will never find the answer.
Every scientific "fact" we rely on has to be provable today, otherwise it is faith based fiction. We tend to confuse the fact that the science that helps us in our daily lives. The science that gives us medicines, computers, cars, TV dinners, and took us to the moon is not the same science that tells us fish turned into frogs, dinosaurs changed into birds, and chance can turn a monkey into a mathematician.
What if the instructions to your microwave said "When you press the START button the microwave might start."
The forces and chemical properties that allow computers and medicines to work are natural and operate the same way every day. Your appliances and medicines never have to be recalled because the physics or chemical properties that science understood when they were created have changed. The properties of chemicals and physics are assumed to be absolutes. And we all, consciously or unconsciously accept these absolutes. We can design a computer, build it and expect it to work because the natural forces that make it work don't change. They are absolutes. What theoretical scientists are often not careful about is placing their inference, deductive and inductive reasoning in place of data and real world physics and chemistry. This is in effect what evolutionism has taught us to do. If we ignore the possibility of intelligence or assume that it was not involved in a process, our conclusions will be greatly skewed no matter how good the data is.