akhp77 wrote:The greatest chance for the existence of extraterrestrial life is on a planet beyond our solar system. The Milky Way galaxy alone contains 100 billion other suns, many of which could be accompanied by planets similar enough to Earth to make them suitable abodes of life.

The statement presupposes which of the following?

A. Living creatures on another planet would probably have the same appearance as those on Earth.
B. Life cannot exist on other planets in our solar system.
C. If the appropriate physical conditions exist, life is an inevitable consequence.
D. More than one of the suns in the galaxy is accompanied by an Earth-like planet.
E. It is likely that life on another planet would require conditions similar to those on Earth.

What do you think about D and E?

OA: E

The argument assumes that due to sun the planets in the solar system becomes suitable abodes of life therefore IMO D. Plz explain y E ?

IMO D.
Please explain why E.The argument does not discuss abt the conditions required to live on Earth or another planet.
Conditions on other planet might be different from Earth and yet it could support extrasterrestrial life.

What's the source of this question? and what is the official answer please?
I feel that option D is redundant since it does not add any new assumptions to the argument. Not sure about option E since I could not link it to the argument. What about option C?

akhp77 wrote:What do you think about D and E?

Hi akhp77,

The argument claims that the greatest chance of life is beyond our solar system because the rest of the galaxy has many other suns which could have planets "similar enough to Earth to make them suitable" for life.

In fact the assumption (the presupposition) here is that the more similar to earth a planet is, the more suitable for life it is. That's what E is saying. If this were false (if similarity to earth had nothing to do with chance of life), the argument would make no sense. Because E states the assumption, it is correct.

D is not correct because it goes further than the argument; D is not an assumption of the argument. The argument says that the galaxy has lots of suns, many of which "could" be accompanied by earth-like planets. This is an argument about probability (likelihood of life) not certainty. D goes further by making a certain claim: "More than one sun is accompanied by an Earth-like planet."

The argument neither claims this, nor relies on it, but simply states that in terms of likelihood (probability), it is more probable ("the greatest chance") that life would come from outside our solar system (thus from the rest of the galaxy) because statistics (lots of other suns which could have earth-like planets) just favor that possibility.

If you have trouble with advanced assumptions questions, you can use the Drill Engine to set topic="CR Assumption" and difficulty="700+"; this should give you high level practice in a timed environment.

Hope that helps,
-Patrick

Hi Patrick,

Thanks for explanation.