It's reasonable to assume someone is truthful when they incriminate themselves.
There is having good reason to believe testimony and then there is blindly believing testimony. What you ought to do is try to show that someone here is doing the latter... rather than asking: "Since you believe this testimony, why don't you believe all testimonies?" That's a ludicrous question to ask.
There is having good reason to believe testimony and then there is blindly believing testimony. What you ought to do is try to show that someone here is doing the latter... rather than asking: "Since you believe this testimony, why don't you believe all testimonies?" That's a ludicrous question to ask.