Let me dissect this 4 infallibles concept further. The shia (porus) contends that only hadith transmitted by these 4 can be considered authentic because they are infallibles. And no human after these 4 can be considered as infallible. Now if that were to be true, then none of the hadith that the shia have today can be considered to be authentic doesn't matter where they came from. Let me prove this to you. Please pay attention as it gets really confusing.
The prophet's hadith were understood and transmitted correctly only by the 4 infallibles. None of the other sahaba of the prophet (saw) were infallibles. Hence, anything that is transmitted by them cannot be considered authentic. Now, consider a group of people that recieved the knowledge of the hadith directly from the 4 infallibles. We will refer to this group as Group A. All hadith that Group A recieved are authentic.
Group A then transmitted these hadith to Group B. However, since none of the people in Group A are infallible, Group B cannot trust any hadith as authentic. Group B then transmitted these hadith to Group C. Same story. Nothing that Group C recieved will be considered authentic. Since we can safely assume that none of the shia living today belong to Group A, we can safely say that none of the shia have the authentic hadith of the prophet (saw).
This is the dissection of the porus view.
Now consider the bohra view. Group A has an infallible. Group B has an infallible, Group C has an infallible and so on and so forth.
Hence the bohra view is far more logical than the porus view. Who knows, I would've remained a bohra if the last infallible hadn't turned out to be a fraud.
![Wink :wink:](./images/smilies/icon_wink.gif)