Two snowflakes never are the same,  The scientists agree;  But have they proved what they proclaim?  I watch the myriads that fall  And leave it up to chance,  That here and there among them all  Twin snowflakes dance. Velma West Sykes

What is Science?  Who defines "Science"?

Historically, "scientific evidence", broadly defined, had to be "generally accepted as reliable" in the field in which it belongs before courts would admit opinion testimony based on a particular technique or discipline.  (Frye v. United States--1923.)   In court, such general acceptance was established by the testimony of experts in the particular field. In 1993, however, the United States Supreme Court altered the rule of admissibility, at least for the federal courts, by stating that Frye's "general acceptance" test was not the sole determinant in the decision to admit or deny admission of proffered opinion evidence. (Daubert v. Merrell Dow Pharmaceuticals--1993.)  The Daubert decision changed the approach to admissibility in at least two significant aspects: (1) henceforth, the test for admissibility of evidence based upon "scientific knowledge" was not to be merely general acceptance in a particular field, but whether proof of "reliability" (validity) of a technique or scientific method could be established; and (2) this determination of reliability  was to be made by the trial judge, upon whom the duty now falls to keep evidence based on unreliable "science" from breeching the gates of the edifice where justice is to be dispensed.  Is it fair to equate "unreliable science" with "junk science"?

Once a "science", always a "science"?

Phrenology was defined as the science "devoted to the identification of basic brain functions and their manifestations in cranial features."  While in modern times we may "think of it as harmless quackery practiced upon the gullible at country fairs", . . .  in 1840, phrenology was a confident science, promising  clear and certain knowledge concerning the mental attributes and behaviors of human beings. . . . There were conferences and symposia. There were professional associations. There were lengthy learned tomes and scholarly journals. The first issue of the American Phrenological Journal had just appeared in October of 1838.@  Phrenology's basic principles were established be the renowned Dr. Franz Joseph Gall.  [See, Pierre Schlag, "Commentary--Law and Phrenology", 110 Harv.L.Rev. 877 (1997).] 

A Standard Proposed for Judging "Junk" Science or "Junk" Expert Testimony:

Keeping in mind that the "factors" of the Daubert opinion may not be appropriate for all forms of expert testimony, consider using the following criteria:

- Are the underlying premises upon which a technique/method rests empirically validated?

- Is there a professional literature that describes the purposes to be achieved and the methods whereby the aims of the field can be reliably realized?

- Are there professional associations or societies offering continuing education to which members with established credentials are eligible to belong?

- Does there exist a rigorous training program whereby one can achieve basic proficiency in the discipline under the supervision of persons with established credentials who can impart knowledge and experience to trainees seeking to qualify as examiners?

- Is there a meaningful certification program that attests to the competence and proficiency of workers in the discipline?

- Has an examination protocol  been developed whereby investigations can be reliably carried out and which will yield reasonably consistent results when followed by properly credentialed examiners? 
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¹Part of an Abstract for a discussion by Professor Andre A. Moenssens delivered at the National Conference on Science and the Law on April 15, l999, at San Diego. The Conference was co-sponsored by the National Institute of Justice and several other organizations.