Scientific Disagreements

From: Susan Cogan (
Date: Tue Oct 17 2000 - 15:53:44 EDT

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    This was posted on another list by Herbert Borteck. It is reposted
    here with permission. It seems to pertain very strongly to how the
    Scientific method and peer review work.

    Scientific Disagreements

    All humans have social and psychological problems which interfere
    with their attempts to be objective. When new ideas and
    modifications of old theories are presented, people will react to
    them depending on how these ideas will affect them. Science is an
    error correcting process. Science thrives on open and free debate
    about the merits of rival hypotheses. Sometimes many rival
    hypotheses are considered before the best is found. It's the nature
    of scientific inquiry that scientists publish hypotheses that may
    later be disproved by new evidence and replaced by a better rival.
    Eventually some hypotheses receive sufficient positive evidence.
    They become accepted as theories with the understanding that even
    the best theories may be revised in the light of new evidence. No
    method exists to take data as input and produce true scientific
    theories as output. Linus Pauling said: "A student once asked me,
    'Dr Pauling, how do you go about having good ideas?' and I answered:
    You have a lot of ideas and you throw away the bad ones."

    This method works both for individual scientists and for the
    scientific community. Plausible ideas need to be published,
    subjected to debate, challenged with new evidence. If a hypothesis
    turns out to be bad, science throws it away. If it stands up in the
    face of further evidence, then the scientist who first published it
    receives the credit. Scientific inquiry is an on-going process of
    error correcting.

    In one of the major scientific undertakings of his life, Lord Kelvin
    was in error. His calculations of the age of the earth were made
    obsolete by the discovery of radioactivity. Lord Kelvin had based
    his mathematics on the earth's cooling from a molten mass. The two
    questions were what is the source of the sun's heat and how old is
    the earth? The earth was assumed to have cooled with only the sun
    for an additional energy source. Lord Kelvin seriously considered
    the collision with meteors as a source of fuel for the sun and as
    impact energy for the earth. But calculations showed that even the
    highest estimates of meteors hitting the sun would only sustain it
    for a few thousand years. He suggested that the sun was slowly
    contracting and in that way produced heat.

    Beginning in 1862, and for thirty years after, Lord Kelvin published
    papers arguing that, according to his calculations of the rate of
    the earth's cooling, the earth could not possibly be old enough for
    either Darwin's evolution by natural selection or for the
    uniformitarian scenario for the formation of the earth's features.
    He said that a fundamental assumption of uniformitarianism was
    contrary to natural laws. According to principles of thermodynamics,
    since the earth was a cooling body, it could not have been at the
    present temperature and with the present conditions for hundreds of
    millions of years. As Lord Kelvin refined his calculations, his
    estimates of the age of the earth went down, from 400 my to 100 my
    to 50 my to 20-40 my.

    What Lord Kelvin lacked was radioactivity. Ernest Rutherford
    discovered that the source of radioactivity is disintegration of
    the atomic nucleus. As a radioactive element disintegrates it ejects
    particles and releases heat. Upon receiving this NEW information,
    Lord Kelvin would not be convinced but most other physicists were.

    Rutherford was about to give a speech on radioactivity in which he
    disagreed with Lord Kelvin's estimates of the age of the earth when
    he realized Kelvin was in the audience. "I… realized I was in
    for trouble at the last part of the speech… Then a sudden
    inspiration came and I said Lord Kelvin had limited the age of the
    prophetic utterance refers to what we are now considering tonight,
    radium! The old boy beamed upon me." Rutherford concluded his
    speech, before the Royal Society, with… "The discovery of the
    radio-active elements, in which their disintegration liberate
    enormous amounts of energy, thus increases the possible limit of
    the duration of life on this planet, and allows the time claimed by
    the geologist and biologist for the process of evolution."

    Lord Kelvin never published any acknowledgment that radioactivity
    was supplying heat to the earth's crust and that thus his
    calculations of the age of the earth were not accurate.
    J.J. Thompson, related in his own memoirs that "in private
    conversation Kelvin did concede that his theories had been


    I am aware that the conclusions arrived at in this work will be denounced by some as highly irreligious; but he who denounces them is bound to shew why it is more irreligious to explain the origin of man as a distinct species by descent from some lower form, through the laws of variation and natural selection, than to explain the birth of the individual through the laws of ordinary reproduction.

    ---Charles Darwin

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