tjmiller:
What is needed is to examine every single usage in Sacred Scripture of the terms “brother” and “sister”, in the original languges.
I did this some years ago, and it proves quite clearly that the traditional Catholic understanding of “Jesus’ brothers and sisters” is correct.
Hi TJ, fact is a word gets its meaning from the immediate context, not from how it is used elsewhere. The scriptures were written over thousands of years so, one would expect a word to have different meanings in different eras.
For example, the Jehovah’s Witnesses try to get out of “I and the Father are one” in John 10:30 by appealing to how the word one is used in John 17. In John 10, Jesus is saying that he and the father are of one essence, one nature. In John 17, Jesus is speaking about one in agreement or of the same mind – thus to prove if brothers, and sisters means blood brother, step brother or cousin one must examine the context of use.
Frankly, I call my half siblings, step siblings and blood or ful siblings brother and sister reguardless of their physical relationship. The best we can say is the text does not have enough information to be sure if these are full blood, half blood, step, or cousins.
Simply ask, your protestant friends what they know about Joseph, is he older than Mary? same age? first or second marriage? did he die or simply run off in the later parts of the gospels? Why is he not present in Jesus life? and so on.
The best we can say is we do not know if those are full blood siblings.