Sherman Kent's 1964 'Words of Estimative Probability' proposes a single-dimension words-to-odds scale, with no axis for source honesty or reliability

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Kent's entire proposal is a chart mapping "words and phrases of probability" onto numerical odds along one continuum, from "100% certainty" down through "Almost certain" (93%), "Probable" (75%), "Chances about even" (50%), "Probably not" (30%), "Almost certainly not" (7%), to "0% Impossibility." He frames the whole essay as a dispute between two camps over how to communicate this single quantity — degree of confidence — not a dispute over source trustworthiness: "Quite figuratively I am going to call them the 'poets' — as opposed to the 'mathematicians' — in my circle of associates... Their attitude toward the problem of communication seems to be fundamentally defeatist." The chart's governing concern is calibrating a word to an odds-value: "We began to think in terms of a chart which would show the mathematical odds equivalent to words and phrases of probability." At no point does the essay propose or discuss a second axis for the source's honesty, reliability, or motive to deceive.

One adjacent aside survives a close read without becoming part of Kent's own proposal: he mentions, as an existing practice he did not invent, "the letter-number device which has been standard with attache and other reporting services, A-2, C-3, F-6, etc." — a letter apparently grading the source and a number grading the report's probable truth. He cites it only in passing, among several "heresies among the mathematicians," without elaboration or a named inventor; it is not Kent's own scheme and does not supply the honesty axis his own proposal lacks. This single-axis document is one of the two primaries Icard's later taxonomy compares its own probability table against.