I am well aware of the work of the Jesus Seminar. The members of this group are very liberal scholars, many of whom do not even believe in God. For me, it is difficult to talk about this group without feeling some anger, as they feel that a group of men in a room can decide whether Jesus did or did not say something recorded in the Bible. They seem to think that they would know better than John or Matthew, who were actually in the room when many of the recorded events happened. This seems arrogant to me. Their methodology is questionable at best. They approach questions about the reliability of the Scripture using particular criteria. Who chooses this criteria? Their methodology is to assume that nothing in the gospels is genuine unless they can find some criterion to assume that it is. One of their assumptions is that Jesus did not do any miracles. This is a false assumption, obviously, but in any case to simply assume something to be true, and then to use the conclusions you reach using this assumption to prove the original assumption is circular reasoning. There is a lot of circular reasoning in the work of the Jesus Seminar.
The biggest problem with what the Jesus Seminar does is that they are flat wrong. God does exist, Jesus is in fact the Son of God, he was in fact resurrected from the dead, and he did in fact fulfill the Messianic prophecies. They assume before even beginning their “investigation” that all of these things are not true. Obviously, beginning with false assumptions causes one to reach false conclusions. Such men claim to be “rational,” but their standard of rationality is human reasoning which denies altogether God as a source of authoritative knowledge. I believe there is a place for asking questions about biblical sources, whether there are in fact contradictions in the Bible, whether the commonly accepted authors of particular books are in fact the actual authors and other similar questions, but I absolutely reject the conclusions of the scholars in the Jesus Seminar because they make unwarranted assumptions in their methodology–assumptions which are flat out not true. You can safely disregard nearly all of the conclusions of the Jesus Seminar.
You say that “there must be and equally learned and rationally convincing response to the Jesus Seminar. There certainly is. I suggest you read my book Reasons for Belief (available at www.ipibooks.com). This book is chock full with rational evidence that Jesus was resurrected, that Jesus fulfilled the messianic prophecies, that he worked miracles, that the Bible is a reliable source of historical information and much more. Also, I suggest you spend some time at my web site, looking around for evidence that supports the inspiration of the Bible. There is a lot there.
The Westar Institute says that they think Jesus is an exceptional man but not the Son of God. There is a problem here. Jesus claimed to be God (John 8:58). He claimed to be the resurrection and the life (John 11:25). Jesus said that the entire Old Testament was written about him, and that he fulfilled all the messianic prophecies (John 5:39, Luke 24:44). If these claims of Jesus are false, then he was not a good person. He would be a false witness. What is the basis for the Westar Institute people thinking that Jesus was an exceptional man if he deceived people and made false claims about himself, or even if his absolutely closest associates lied about him? This is not logical or reasonable.