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(Comparative Anatomy and Physiology Brought Up to Date--continued, Part 1B)

Brief Overview--What is the
Relevance of Comparative Anatomical/Physiological "Proofs"?

Comparative anatomy and physiology (as well as more general comparative approaches that incorporate additional information) are often cited by advocates of particular diets as providing "proof" that the diet they promote is humanity's "natural" diet, and hence best or optimal in some sense. The object of this paper is to examine, in detail, the claims made in the assorted "proofs" based on comparative studies.

To be fair, it should also be pointed out that some of those presenting comparative studies openly admit that such studies do not provide hard proof of the natural human diet, but instead merely contribute evidence in favor of the particular diet they advocate.

Along the way, this paper will address many of the claims made in:

Other claims: Over and above claims made in the above "classic" sources in the alternative dietary literature of the past, an extensive cataloguing of other claims typically made as part of such comparative "proofs" is also reviewed and discussed. As well, a number of other assertions that go beyond comparative anatomy/physiology itself but that often come up in discussions related to the issue of omnivorous vs. vegetarian diets are covered here for completeness, since they will be of keen interest to those interested in these subjects.

Citations for these claims are not given, as in some cases the sources are, in my opinion, extremists (often fruitarians); and citing such works by author's name may needlessly inflame and detract from a focus on the issues themselves, or might merely incite personal attacks by hostile but allegedly "compassionate" extremists. The approach taken here will be to paraphrase the latter claims, trusting that readers will be able to recognize such claims and their proponents should they subsequently run across them elsewhere.

The Logic and Structure of Comparative "Proofs"

The basic argument underlying comparative anatomy/physiology "proofs" is that comparing humans with other species--via a list of anatomical and/or physiological features--somehow "proves" that humans have a particular, often quite specific/narrow, diet. This conclusion is allegedly reached if sufficient features match in the comparison list.

Subjective nature of traditional "proofs." However, examination of the various "proofs" reveals considerable variation in length of lists used for the comparisons, in the level of detail in each list, and in the number of supposedly matching features provided as "proof." In addition to the question of whether the method is logically valid to "prove" the human diet is restricted to a narrow range, one immediately observes that there appears to be considerable subjectivity in determining the level of detail in the comparison list. And, for that matter, just how many "matches" are required for "proof," anyway? (And what validation is there for such a "magic" number of matches?)

What do comparative "proofs" actually show? As we will see later, comparative anatomy and physiology are not so precise as to give definitive, narrow answers to the question of what is the natural diet of humanity. Instead, comparative anatomy and physiology provide evidence of associations and possibilities. We will also see that those who present simplistic comparisons, and claim they absolutely "prove" humans naturally must follow a narrow, restricted diet (e.g., fruitarianism, for example) are not telling you the whole story. Unfortunately, this pattern--giving you only a small part of the information available (in figurative terms, half-truths)--is common in the raw and vegan movements at present (in my opinion).

Comparative Anatomy and Physiology
are Legitimate Tools

It should be emphasized, and very clear to readers, that comparative anatomy and comparative physiology are legitimate, useful, and important tools for scientific inquiry and research. In particular, the following are relevant:

Comparative anatomy is a valid tool, but simplistic applications are often fallacious. The basic question of this paper is not whether comparative anatomy and physiology are valid tools (they clearly are, though we will see that applying comparative anatomy and physiology to humans is problematic), but whether the simplistic analyses presented by dietary advocates are legitimate or "scientific" (we will see later that they are not). So, the question here is not whether the tool is valid, but the specific application of the tool--i.e., whether the tool is being used honestly and properly.

Emphasis on Primates

Modern human beings, species Homo sapiens, are classified as belonging to the primates. Accordingly, as this paper focuses on comparisons, the non-human primates will often be used for comparison. Humanity's prehistoric ancestors--extinct primates, including both human and non-human species--are also discussed as appropriate. When necessary, non-primate species are discussed as well, but most attention here is on primates.

Helpful Notes for the Reader,
and Special Terminology

I hope that you find this paper to be interesting, that the material here is "mentally digestible," and that you will use the information as a positive opportunity to examine the assumptions that underlie your personal dietary philosophy. Enjoy!


(Ape Diets: Myths, Realities, and Rationalizations)

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GO TO PART 1 - Brief Overview: What is the Relevance of Comparative Anatomical and Physiological "Proofs"?

GO TO PART 2 - Looking at Ape Diets: Myths, Realities, and Rationalizations

GO TO PART 3 - The Fossil-Record Evidence about Human Diet

GO TO PART 4 - Intelligence, Evolution of the Human Brain, and Diet

GO TO PART 5 - Limitations on Comparative Dietary Proofs

GO TO PART 6 - What Comparative Anatomy Does and Doesn't Tell Us about Human Diet

GO TO PART 7 - Insights about Human Nutrition & Digestion from Comparative Physiology

GO TO PART 8 - Further Issues in the Debate over Omnivorous vs. Vegetarian Diets

GO TO PART 9 - Conclusions: The End, or The Beginning of a New Approach to Your Diet?

Back to Research-Based Appraisals of Alternative Diet Lore

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