Tag Archives: Vagueness

Project Logicality | Slippery Slopes


Screen Shot 2016-04-07 at 21.28.48I discuss here the Slippery Slope, which has both a causal and semantic version.

But first I’ll deal with its causal version, the Fallacy of the Beard, also the Camel’s Nose fallacy. The first name comes from an analogy with the greying of a man’s beard, in which the amount of grey is small at first, but inexorably progresses until the entire beard is grey. The second  name comes from a fable in which a camel is permitted by its owner to stick its nose in the tent for warmth from the cold desert night air, quickly followed by the entire camel, who crowds its owner out of the tent and into the cold.

Afterward, I’ll discuss the semantic version, the Vagueness, or False Continuum.

The first asserts that a position or claim is unacceptable because if accepted, its extreme must inevitably follow, without sound reasons as to how or why this must be.

A superficially similar form of argument can be a strong line of reasoning when the chain of inference is laid out and logically follows, but this refers to the specious usage, as below:

The public teaching of comparative religion leads to awareness of religious diversity, then to religious doubt, then to agnosticism, then to atheism, then to anti-theism, then to nihilism, then to moral degeneracy, then inevitably to the disintegration of a society in total anarchy, so we don’t want comparative religion courses taught in our public schools.

Beside the fact that the evidence just doesn’t bear this ridiculous chain of consequences out, note here that no supporting reasons or other justification are ever provided as to why this chain must be true.

The semantic Vagueness, or False Continuum, is below:

One version attempts to argue that concepts B and E shade into each other along a continuum without any fine dividing line between them, so they are the same thing.

But it just doesn’t follow that:

There is no difference between blue light and yellow light, despite no sharp dividing point in wavelengths in the visible spectrum.

Nor does it follow that:

There is no separation between humid or dry weather when the moisture in the air at any one time and place varies in degree from high to low.

The second variant is used to argue that concept B differs so little from concept E with no fine line between them, that concept E simply doesn’t exist. As for this one, it doesn’t follow that:

Truth doesn’t exist because of the continuum between truth and falsehood. The concept of truth is without any objective reference.

These two fallacies, causal and semantic, are distinct, but they are mentioned together here as the use of the semantic version can and does often lead to the commission of the causal version. Their joint use implies that a slip from position or claim B to E is inevitable because of the lack of a fine point of separation between them.

Logical Fallacies — the Slippery Slope


Hey, guys. This post deals with an informal fallacy known as the Slippery Slope, the causal version known also as the Fallacy of the Beard, or the Camel’s Nose fallacy. This argument takes the form of a statement that assumes that a position is unacceptable because if it is accepted, the extreme of that position must inevitably follow, without any sound justification as to why. This can sometimes be a strong line of reasoning when the chain of argument is fully laid out and logically follows, but we concern ourselves here with the specious usage, and an example is below:

The public teaching of comparative religion leads to religious doubt, which leads to agnosticism, which leads to atheism, which leads to anti-theism, which leads to inexorable nihilism, which leads to moral degeneracy, which inevitably leads to the disintegration of a society now characterized by total anarchy, so we don’t want comparative religion courses taught in our public schools.

Aside from the fact that the evidence just doesn’t bear this ridiculous chain of consequences out, note that no supporting reasons or other justification are ever provided as to why this chain must be true.

The other major version of this fallacy, the semantically-based Vagueness, or False Continuum, is used in one variant in which the argument is made that concepts B and E shade into each other along a continuum without any real demarcation between them, therefore they are the same thing.

But it just doesn’t follow that there is no difference between blue light and yellow light, despite the lack of a sharp dividing point in wavelengths in the visible spectrum, nor does it follow that there is no demarcation between humid or dry weather when the moisture in the air at any one time and place varies in degree from high to low.

The second variant of the False Continuum is used to argue that concept B differs in only insignificant ways from E without any real demarcation between them, and that therefore E simply doesn’t meaningfully exist because of a lack of said demarcation. As for this one, it doesn’t follow that truth doesn’t exist merely because of the continuum between truth and falsehood, that the concept of truth is utterly without objective reference.

These two fallacies, causal and semantic, are distinct, though sharing the same general name, and they are mentioned together in this post because the use of the semantic version can and does often lead to the commission of the causal version, the idea that a slip from B to E is inevitable because of the lack of a fine point of separation between them.

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