First of all, I have a LOT of material on the teleological argument. In fact, my book Is There a God? is primarily a book which uses the teleological argument. You ought to get a copy at www.ipibooks.com. Also, if you do a search of my web site for the term God and Science you will find a power point and audio of a lesson which is, mostly, based on the teleological argument. I love the Cosmological Argument because of its simplicity. Personally, I was convinced of God based on the Teleological, not the Cosmological Argument, but it is not as simple an argument, as the discussion below will show.
The video you found is well-put together. The person is arguing without appeal to emotion or rhetoric, and for that his video deserves some praise for avoiding some of the errors many non-believers such as his friend Christopher Hitchins have made.
However, his logic is faulty. In fact, it is very faulty, but the reason it is faulty is fairly subtle and, like I said, given that he is wrong (ie given that there is a Creator), he did a pretty good job! For that he deserves some credit.
So, let me explain. First of all, this gentleman makes the false claim that the argument from design is entirely an argument based on complexity. In fact, this is the first thing he says, which means that right of the gate, his entire argument has a really big problem. This is simply not true (that the watchmaker/teleological argument is entirely an argument based on complexity). He completely ignores the strongest group of facts which support the teleological argument, which is the absolutely astounding level of fine-tuning in the universe. Fine tuning is not complexity!!! Fine tuning is about precision, not complexity! Fine tuning is about a fact which requires an astounding level of coincidence unless it is in fact designed. This is the anthropic argument, which is a subset of the teleological argument. (much on this in the book and audio mentioned above) Second, I believe that the second strongest argument for design, after the fine tuning data is the existence of information. Nature never creates information without the previous existence of information. Information and complexity are not the same thing. This gentleman may or may not be aware of the concept of entropy, and I doubt he is aware of the concept of informational entropy. Does the universe ever create complexity? Yes, although not the kind of complexity in a living thing, but like I said, complexity is at least two levels down the list as far as kinds of things that exist in the universe that requires an intelligent Creator. It certainly comes behind the need to explain the fine-tuning and the existence of information. If you read my book, you will see that I literally do not even use a complexity argument for design. I have an entire chapter on informational entropy you should read. Complex things do not necessarily have a low amount of entropy, but systems with information do have an extremely low level of entropy, and an kind of low entropy that is never achieved in nature spontaneously. Never! And I am not exaggerating.
A few more things. He mentions a couple of logical fallacies. His awareness and use of logical fallacies is the strongest part of his argument, in my opinion, but I believe that the argument for design does not require the use of any of these fallacies. He mentions that correlation does not equal causation. That is true. But correlation does not disprove causation either. However, he notes that correlation does not prove causation and then concludes that the complexity of the universe was not caused. This is bad logic. I will agree with him that complexity alone does not prove a Creator, but it will depend on the kind of complexity and, besides, there are two even stronger arguments for a designer (information and fine tuning) which do require causation. Does the existence of complexity, by itself, prove the existence of a designer? The answer is not necessarily, but certain kinds of complexity do require a designer. But that misses the whole point, which is that the universe comes pre-loaded with more kinds of design than its complexity.
He then goes on to say that he can prove that nature produces complexity. By the way, I will agree with him that nature does spontaneously produce certain kinds of complexity, but, like I said, not every kind of complexity. The fallacy in his argument from evolution is that evolution requires that life already exists. Evolution is a means to produce new species from already-existing species, but it is not a means to produce life. This person simply ignores that rather crucial fact! Living systems have a massive amount of information already contained in the system. No one ever argued that existing systems which already have a lot of information in them can produce more information. Artificial Intelligence is an example of this. So, by the way, is evolution. Here is the point. I will grant without any resistance at all that living things evolve by a purely natural process. They can even create new information by this process. Here is what cannot happen. Systems with no information at all cannot create new information. All attempts to create a model for the spontaneous creation of useful proteins involve computer programs into which a significant amount of information is put into the system before it is run. Nature can produce complexity, but it does not produce information. Ever. Period. End of story. Therefore, evolution, which is a process that occurs in living things which have a vast amount of information already input into them are a totally inappropriate model for supposedly disproving that nature can produce complexity (or information, for that matter) where there was none before, which he is claiming to prove. Therefore, his argument in this case collapses.
He then makes another argument that the reason we know that the watch has design is because we know it was designed. This is NOT TRUE. Now, I will admit that we know that watches were designed. However, if we were dropped onto a planet about which we knew absolutely nothing and if we saw a pocket watch, we would know that it was designed. We know the watch is designed, not because we know it has a designer, but because common sense tells us, without any conceivable possible counter argument, that watches are designed. His argument here is completely fallacious. Watches require designers. Watches do not happen spontaneously in any universe. Similarly, the universe requires design and life requires design. Both have kinds of design inherently contained within themselves, that tell us a designer is required, even if we do not know the history of these things. Again, his argument sounds logical, but it simply is not. It is a cute argument, but it is a fallacious one.
He finishes by telling us that, even if we can establish the validity of the teleological argument, this would not prove any particular religion. It is interesting that he seems to anticipate that most of his hearers will realize that his arguments are not particularly strong, given the incredible level of fine-tuning (which he ignores) and the amount of information contained in living things (which he also ignores). So he seems to make a just-in-case argument. By the way, I will have to say that I completely agree with his argument in this case. If we can prove that the universe is designed (which we can, or at least, we can show that this is by far the most reasonable conclusion), then this does prove theism. He is right there. What it would prove is that either deism is true or theism is true, but that atheism and agnosticism are false. I have conceded this point many times. The teleological argument is an incredibly strong one. It is virtually unavoidable, and this gentleman’s arguments do nothing to undermine this. However, the obvious existence of design does not logically lead to theism–the view that the Creator actively intervenes in his creation. In this, the author of the video is correct. My belief in theism is not based on the teleological argument at all. However, his stated purpose, which is to disprove the teleological argument is a complete failure. No wonder he adds his last little point about theism.