Wegener, Mechanism and the Standards of Rejection
When Alfred Wegener proposed in 1912 that the continents had once been joined and had since drifted apart, he could point to a striking set of coincidences: the fit of the South American and African coastlines, identical fossil plants in rocks of the same age on either side of the Atlantic, and glacial deposits in what are now tropical latitudes. What he could not supply was a force capable of moving continents through the ocean floor. Physicists of the period calculated that the required forces were implausibly large, and geologists who had spent careers mapping rock sequences saw no need for a mechanism their own data did not demand. The idea was set aside for four decades, until palaeomagnetic surveys of the ocean floor revealed symmetrical stripes of alternating magnetic polarity on either side of the mid-ocean ridges. It is often said that science advances one funeral at a time. Wegener's case suggests something narrower: a hypothesis that fits the evidence but offers no mechanism may reasonably be judged premature without being judged wrong.
1. State the author's main claim about why Wegener's theory was rejected, and explain how the final sentence modifies the common saying about funerals.
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Main claim. The rejection was not simple conservatism or stupidity: it followed from a defensible evidential standard. Wegener's case was descriptive - fits, matches, coincidences - while the physics of the day required a force that could not be supplied. A theory that explains the pattern but cannot say how it happens leaves the discipline with no way to test it further, so setting it aside was a rational holding position.
The funeral saying. The saying implies that individual scientists are obstacles who must be removed before a correct idea can win. The author narrows this: the obstacle was the absence of a mechanism, not the age of the objectors. The moment seafloor spreading supplied a mechanism, the same generation accepted the idea.
Consequence. 'Premature' and 'wrong' come apart. Rejecting a claim because it is untestable with current tools is different from refuting it, and the passage is careful to keep that distinction.
2. A student concludes from the passage that the geologists who rejected Wegener were being unscientific. Does the passage support that conclusion? Justify your answer with reference to specific details.
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No - the passage supports the opposite reading.
Evidence in the text. (i) The author says the rejection 'was set aside', not that it was refuted; (ii) the physicists' calculation that the required forces were 'implausibly large' is a quantitative objection, exactly the kind of check a scientist should make; (iii) the author's closing sentence explicitly separates 'premature' from 'wrong'.
What the student has done. They have applied a hindsight standard: because Wegener turned out to be broadly right, anyone who doubted him must have been irrational. That is a classic error - judging the quality of a decision by its outcome rather than by the information available at the time.
A defensible version of the student's point. One could argue that the fossil and stratigraphic matches were strong enough to justify keeping the hypothesis alive as a research programme rather than shelving it. That is a criticism of how thoroughly the idea was pursued, not of the reasoning standard used to reject it.
3. Which later finding in the passage most directly answers the objection that sank Wegener's theory, and why does it do so more effectively than the earlier coastline and fossil evidence?
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The symmetrical magnetic stripes. They answer the mechanism objection, which is precisely the objection the passage identifies: the earlier evidence was entirely static and descriptive, while the stripes record a process.
Why symmetry matters. Matched stripes on both sides of a ridge imply that new crust forms at the ridge and moves away in both directions at a roughly constant rate. That converts 'continents move' into 'the ocean floor moves and carries the continents with it', which is testable: spreading rates can be calculated and checked against dated rocks.
Why the earlier evidence could not do this. Coastline fit, shared fossils and glacial deposits are consistent with continental drift, but also with land bridges that later subsided, or with a static configuration plus a different climate. They constrain where the continents were, not how they got there.
General lesson. Evidence that a hypothesis fits is weaker than evidence that identifies its machinery; the latter also generates new predictions that could have failed.