December 2010, Section 4, LR, #18 "Sentient Beings" Forum

[secretad]

I really struggle on sufficient assumption questions. I am scoring 170+ on my preptests, but I cringe when I see a sufficient assumption question. On a question like this one, I really leaned towards not diagramming it. I mean I gathered that it is essentially:

Premise: If SB on planets outside solar system --- > ~Determine

Premise: ~Spacecraft

Premise: SB on another planet capable of communicating in the near future ---> at least as intelligent as humans

Conlcusion:
Determine ---> SB at least as intelligent as humans


I also took notice of the varying phrases in the stimulus, going from planets outside our solar system, to later on saying another planet, regardless of whether or not it is in our solar system.

The correct answer is D.

[510Chicken]

D) If a sentient being on another planet cannot communicate with us, then the only way to detect its existence is by ending a spacecraft to its planet.

This can be written as:
D --> (C v S) (D = Detect/Determine; C = Communicate; S = Spacecraft)

Since ~S is given:
D --> C

C --> I (I = Intelligent) (Given)
So:
D --> C --> I
D --> I

Which, incidentally, is the conclusion you're looking for.
(or alternatively, ~I --> ~C --> ~D)

[lakers3peat]

D) If a sentient being on another planet cannot communicate with us, then the only way to detect its existence is by ending a spacecraft to its planet.

This can be written as:
D --> (C v S) (D = Detect/Determine; C = Communicate; S = Spacecraft)

Since ~S is given:
D --> C
)[/quote]


Is that really inferrable? Jeez I had so much trouble with this question; I thought I had my formal logic down but I guess I dont



Op: you might want to revise your post to remove the infringement, at least paraphrase