Logical Reasoning

PT104 · S4 · Q9 The only physical factor

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The only physical factor preventing a human journey to Mars has been weight.

Conclusion (therefore)

It's possible for people to go to Mars and back, using this device.

Evidence

What was currently preventing a round trip was the weight of the fuel we would need. We couldn't launch something that heavy.

This device will allow us to take half as much fuel, because we can create fuel from the Martian atmosphere for the return trip.

Evaluate

Because this is giving off Plan / Goal vibes, I would probably eschew looking for a missing link and try to think of potential Plan objections.

Is it not feasible to use this device? (can we launch this spaceship from earth?)

Would it fail to cooperate as intended (like could it really make fuel from the atmosphere? how long would that take? what if weird conditions thwarted the process?)

Could it backfire? Could this device somehow make the craft even heavier?

Goal

The correct answer might link , but more likely it'll rule out some objection to the Plan. We'll probably be using the negation test.

9.

Which one of the following is an assumption on which the argument depends?

  1. The amount of fuel needed

    Too Strong (the same)

    It wouldn't hurt the argument if it takes less fuel to return from Mars then it does to get there. The author doesn't need to be the extreme idea of "identical amounts of fuel".

    7% picked this

  2. The fuel manufactured from the

    Too Strong: doesn't differ

    This has the lovable Defender "not", so let's ask does this negation weaken? hey, author, the fuel we make on Mars will be chemically different than the fuel we used to get to Mars. No. As long as we can use the fuel from Mars to make the return trip, who cares if it's chemically different? The author doesn't need the two types of fuels to be identical in composition, as long as the spacecraft is equipped to run off both types of fuels.

    8% picked this

  3. The device for manufacturing fuel

    Too Strong (wouldn't take any)

    Again, we can quickly negate by removing the "not" and test whether it weakens. Hey, author -- bad news for your plan. This device would take up at least some of the crew's living space. The author would just say, 'sorry for their loss'. It's still possible for people to go to Mars and back, using this device. They still have plenty of room.

    2% picked this

  4. A conventional spacecraft equipped with

    Irrelevant Comparison

    When we negate this, we'd get the potential objection, Hey, a ship with this device would be a good bit more expensive to make! The author will say, "that's irrelevant to my conclusion. I'm only addressing whether it's possible to do it, not how much it costs or whether anyone will or should do it."

    1% picked this

  5. Correct

    The device for manufacturing fuel

    Why this is right

    The author was Assuming a Difference. Conventional ships can't make a round trip to Mars because they're too heavy. If the author thinks this ship + fuel device combo can make the trip, she must be assuming that they are not too heavy, which definitely means they'd be less heavy than conventional ships. If we negated this, it would give us a Feasibility objection to the Plan. "You won't be able to launch this ship + device combo, because it weighs at least as much as the ship that we currently can't launch."

    Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

    83% picked this

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