If a 100% accurate lie detector could be created and (more importantly) if people trusted it to be 100% accurate, than yes, it certainly would be the very best innovation.
In fact: we could even stop prosecuting people for crimes they didn't knew where crimes (or give them lower sentences in some cases)! http://dailysignal.com/2014/01/20/happens-break-law-didnt-know/
Not a single innocent person would end up in prison and a lot more cases would be solved.
It would also make torture a lot more effective... Which could be seen as a downside to some, but it would also stop of a lot of unnecessary torture (because if a person truly "knew nothing about it" and was innocent, he would be able to prove that easily).
I always wondered why traditional lie detector tests weren't used in court until I found out they are expensive, hard to set up and inaccurate. To be able to ascertain the truth should be the top priority for the government and it will help save so many innocents from jail if a true lie detector is created. I would say if this is created, it could not be relied on fully because what a witness believes is not always the truth. The truth is sometimes different for each witness, and witnesses often have pliable memories and can be manipulated, or even recreated by their subconscious in order to be able to handle a tough situation.
I think a 100% accurate lie detector can save americas broken criminal justice system as well as the world. Will tech ever develop something that would be deemed a miracle? And if so, woulf u be happy to see infallible people, who often buy their way out of justice, goto prison? Do you agree thag this hypothetical invention would benefit the world? Excuse my unedited grammar lack oc sentrnce attucuture and argument