#18 - If there are sentient beings on planets outside our

[ryanshort8883]

So I'm able to diagram these kinds of questions relatively well, what gets me into trouble and/or causes me to use way too much time is being able to see the missing link.

I'm still relatively new to this so hopefully more practice will help, but I'm also wondering if there is a more general, almost algebraic, way of doing these types of questions?

Just using this question as an example - I'm looking at my diagram and saying, "Okay, I've got 'As Intelligent' common to both premises and conclusion as a necessary condition, so one possibility is that I need to link X and another possibility is that I need to link Y to get to my conclusion, etc."

I understand that part of what makes these questions hard is that there aren't hard and fast rules that say okay since I have X then Y will ALWAYS be true, but I'm just asking for a general approach/questions I can ask myself to hopefully make these kinds of conditional problems more clear/easier to "see."

Thank you

[Adam Tyson]

Try this approach, ryanshort8883, which is a little more holistic than it is algebraic: first ask yourself what the conclusion is, and what the premises are that supposedly support it. Keep your answers simple, like a summary rather than getting too deep in the details. Here, you might answer this way:

"The conclusion is that if they aren't as intelligent as us, we won't find them any time soon. The premises are that we cannot send a ship or communicate with them directly."

Now, link those two ideas in such a way that if the premises are true, the conclusion must certainly follow. "If we can't send a ship or communicate directly, then we can't find them."

Sometimes, getting out of "diagram" mode can be enlightening and useful. I ask myself these same questions - what are the premises, what is the conclusion? - for most questions, not just Justify the Conclusion questions. This helps me to better understand the structure of the overall argument, and to see its weaknesses. I tend to reserve diagramming for problems that involve multiple sufficient and necessary conditions, or long chains of conditions that need to be linked. See if that approach gives you better insight, and let us know how it works out!

[ryanshort8883]

Great. Thanks, Adam. I like that approach, as I have a tendency to get too zoned in on conditional problems, which can cause me to forget about the big picture.

[ashpine17]

If we only got two options: sending a spacecraft or waiting for the sentient beings on that other planet to communicate with us, that is diagrammed like an either or rule isn't it? /spacecraft---> Communicate with us but do they have the same meaning? Either or rules in logic games means that you have to select at least one option so...I'm a bit baffled because they appear to be diagrammed the same way but idk if they mean the same thing. Could someone clear this up for me?

[Adam Tyson]

You're correct, ashpine, that an either/or statement in logical reasoning has the same meaning as one in logic games, in that if you do not have one of the two conditions then you must have the other. However, in this argument the problem is that the author is assuming that there is an either/or relationship when there might not be. In other words, there could be other options that the author has not considered, like observing those other beings through a powerful telescope, or detecting emissions of radio signals.

To prove that the author is correct, then, we need to eliminate all other possibilities and ensure that those are the only choices available. We need to create that either/or scenario!