- Wed Jan 20, 2021 3:01 pm
That's a really good question, leslie, and I see why you are a bit stuck on it. It does seem somewhat arbitrary, and to an extent perhaps it is. I often say that how you choose to diagram a rule is at least partly a matter of personal style. You have to do what works for you.
To compare these two rules, in terms of what works for me, I see it this way: In the game discussed in this thread, I know that every song is either a rock classic or new composition. I know that means there could be several of each. But I also know that each song appears just once. That's easily memorized, and I can also see it in my diagram because the number of songs I listed matches the number of spaces I drew in my base. To me, a ZR block would never make me think "every R must be a Z," because there will only be a single Z. What it does for me is create a more powerful looking "playing piece" that will completely fill a position in my sequence. It's more visual, and therefore more useful and powerful to me, than a conditional rule.
In that other game, there could be, but do not have to be, multiple 10s. Some of the archaeologists may be used more than once. Creating a block would, to me, invite some confusion about what triggers that block. Was it the G that required the 10, or the 10 that required the G? As I get a few questions into the game I don't want to have to go back and re-read that rule to be sure I understand it. For me, that level of greater uncertainty and flexibility makes the conditional diagram a safer approach. To do it as a block would not be wrong, but you would have to memorize what exactly it means and what it doesn't mean. That, to me, is a distinction that matters.
Ultimately, the choice of how to diagram it is up to you! It's not about what's right or wrong, but about what works for you.
Adam M. Tyson
PowerScore LSAT, GRE, ACT and SAT Instructor
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