this is the wisdom of men, using human logic when Jesus Christ's words are so simple: The one who "believes and is baptized shall be saved," (Mark 16:16) -- you do A (believe), then B (baptism) follows and you shall be saved. You don't do A (believe), then B does not follow, hence you won't be saved. Yet, CHRIST HIMSELF says you MUST do A and then B.
1. Logic gets you correctly from valid premises to a valid conclusion. The conclusion, though it may be logical, will not be true if the premises are not true ("All creatures with six legs are insects. Spiders have six legs. Therefore, spiders are insects." logically valid but untrue.)
2. Logic is not species specific: "If A is contained in B, and if B is contained in C, then A is contained in C" holds whether it's a chimp or and angel or a human who says it.
3. It's true that "If A, then B" does not necessitate "If not-A, then not-B," but it still may be that both are true: "If you are not this height, you cannot go on this ride. If you are this height, you can go on this ride." And in this case, salvation, we're told that the relationship between "A and B" or "not-A and not-B" is the fundamental nature of things:
"Whoever has the Son has life; whoever does not have the Son of God does not have life."--1 John 5:12
No. "AND" is not "THEN".