A: The theory of intelligent design posits that organisms are sui generis, that they arose by design, that all the parts of the organism are interrelated.
Basic biology dictates that an organism must be integrated. There is no reason to assume a designer would be so constrained. There is also reason to assume an intelligent designer would have done a far better job on, for example, the human back and the human knee. If a designer created each species, why introduce variation within that species, and why put so much emphasis on reproduction? If all organisms were intelligently designed, why would some species now extinct?
Q: How can Intelligent Design Theory be falsified?
A: By finding proof that traits and the supporting system to make them work can coevolve and have coevolved at some time or other. In other words, proof of macro-evoltuion.
A condition of falsification must always be part of a theory. A theory cannot be said to be falsified by the discovery of evidence for some other theory. Competing theories regarding the same phenomenon must necessarily be independent. Intelligent Design Theory by this definition explicitly hinges its own existence on the continued viability of evolution. If evolution is ever falsified, then Intelligent Design loses it's falsifiability and therefore must also be abandonded.
Additionally, no theory can ever be proven. Evidence for a theory may be gathered, predictions can be confirmed, but proof cannot be had. Falsification of the Theory of Intelligent Design (as is the case with all theories) must rest on observing some event which runs counter to a prediction of that theory. A theory cannot be said to predict its own assumptions.
To assume a designer as an explanation for the species raises more questions than it answers. OTOH, if one were to hypothesize simply that life originated with a designer/god, then evolution would have nothing to add.
Simple: Somebody bright enough to look at a truck or an airplane and tell that it was designed and didn't just happen ought to be bright enough to look at a dog or a cat and make the same determination.
Wrong, a designer would want everything to work together. However, that is besides the point. Point is that for new adaptations to become gradually integrated you need the new traits to coevolve with the supporting system required for them, otherwise they will be useless (and according to evolution, the whole purpose of new traits is to give a species greater viability). Even very simple things take a very large support system. One example is the lacrimal glands. First you need the gene for the glands. However a gene is just a possible function. It only becomes an actual function when certain cells are assigned to perform the function. Now the cells assigned need to have a certain composition for the function to work, so the creation of these cells needs to have also been assigned during the course of the organism's development. Of course, tears would be useless if they had nowhere to go. So you need ducts for these tears to go through. In addition to which you need to have a mechanism to tell the glands when and how many tears to produce. For this you need a connection between the eye itself and the lacrimary glands telling them when and how much to produce. So you need a message system specific to this purpose.
As can be plainly seen from the discussion above, even a very simple system such as this requires the cooperation of the rest of the organism in performing its functions. It is therefore impossible for it to have arisen as a result of either gradual or non gradual evolution because it would have required the coevolution of many things at random.
A condition of falsification must always be part of a theory. A theory cannot be said to be falsified by the discovery of evidence for some other theory.
The falsification is indeed part of the theory. If it can be shown that new traits, new abilities, new systems can arise without design as evolution posits then the theory of Intelligent Design would be falsified.
As I pointed out in post#627 the latest scientific findings completely support the theory of intelligent design and disprove the theory of evolution. Every single function of an organism requires way more than a single change to be effected. Every single function needs the cooperation of the rest of the organism. Therefore, the new functions which evolution says were created by chance (helped by necessity) could not have arisen that way. You would need many things to have coevolved at once for it to have occurred. According to Darwin himself such a requirement would destroy his theory because it would make gradual evolution impossible.