Wel, that is one of the popular explainations of modern sceptics. But the truth is that man is aware of himself and therefore is aware that the universe exists. With that knowledge he naturally has always questioned his exstence. To question is part of the scientfic process. To limit ones undertanding of the universe to what can be seen or "proven" is to unnecessarily limit man's intellect. What you say might be believable if the Jews had not preserved their faith in the face of the tolerantRoman Empire which wanted all religions to be equal, and thus unimportant and if Jesus had not walked the earth and died after having been predicted 500 years before. His resurection is not a theory, or even a invention. People don't get eaten by lions over a period of 300 years for an invention.
I am confused. I didn't think the Jews believed Jesus to be the Son of God.