Logical Reasoning

PT16 · S3 · Q2 Despite the best efforts of astronomers

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Despite the best efforts of astronomers, no one has yet succeeded in exchanging messages with intelligent life on other planets or in other solar systems.

Conclusion

There is no intelligent life anywhere but on Earth.

Evidence

Astronomers have not succeeded in exchanging messages with extraterrestrial intelligent life and have not even proved that any extraterrestrial life exists.

Evaluate

The argument moves from "we have no evidence of extraterrestrial life" to "there is no extraterrestrial life." That is the absence-of-evidence-vs-evidence-of-absence mistake. Failing to find evidence of something is not the same as proving it does not exist — especially when the search space (the universe) is vast and our search has limits.

Goal

Find the answer that names this flaw: confusing the absence of evidence for X with the presence of evidence against X.

2.

The argument’s reasoning is flawed because the argument

  1. fails to consider that there

    Bad Objection

    Whether intelligent extraterrestrials might be non-living is exotic but tangential. Even granting all extraterrestrial intelligence is living, the argument's flaw remains: it concludes there is no extraterrestrial intelligence solely because astronomers have not found any. The flaw is structural, about how absence of evidence is treated — not about the metaphysics of life.

    3% picked this

  2. Correct

    confuses an absence of evidence

    Why this is right

    This identifies the flaw exactly. The astronomers have not proved intelligent extraterrestrial life exists — that is an absence of evidence for the hypothesis. The argument treats that absence as if it were evidence against the hypothesis, concluding no such life exists. But not having found something does not show it does not exist; the search may be incomplete, the targets may be far away, the methods may be insufficient. Confusing "no evidence for" with "evidence against" is exactly this argument's mistake.

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

    94% picked this

  3. interprets a disagreement over a

    Bad Description

    The argument does not involve a disagreement over a scientific theory. There is no theory being debated and no clash of expert views in the stimulus — just astronomers having not found something. So this misdescribes the structure of the argument.

    2% picked this

  4. makes an inference that relies

    Bad Description

    The argument does not exploit any vagueness in the term "life." Whatever definition of "life" we use, the structural flaw — treating absence of evidence as evidence of absence — remains. Vagueness is not what is going wrong here.

    1% picked this

  5. relies on a weak analogy

    Bad Description

    There is no analogy in the argument. The author does not compare extraterrestrial life to anything else. The reasoning is direct: astronomers haven't found extraterrestrial life, so there isn't any. This describes a flaw the argument does not commit.

    1% picked this

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