Lack of empirical evidence  

Many of Gardner's "intelligences" correlate with the  _g_ factor
 "G factor \(psychometrics\)") , supporting
the idea of a single dominant type of intelligence. Each of the domains
proposed by Gardner involved a blend of _g_ , of cognitive abilities other
than _g_ , and, in some cases, of non-cognitive abilities or of personality
characteristics.  [24]

The Johnson O'Connor Research Foundation has tested hundreds of thousands of
people  [47]  to determine their "aptitudes" ("intelligences"), such as manual
dexterity, musical ability, spatial visualization, and memory for numbers.
[48]  There is correlation of these aptitudes with the  _g_ factor
 "G factor \(psychometrics\)") , but not all
are strongly correlated; correlation between the  _g_ factor
 "G factor \(psychometrics\)") and
"inductive speed" ("quickness in seeing relationships among separate facts,
ideas, or observations") is only 0.5,  [49]  considered a moderate
correlation.  [50]

 Linda Gottfredson  (2006) has
argued that thousands of studies support the importance of  intelligence
quotient  (IQ) in
predicting school and job performance, and numerous other life outcomes. In
contrast, empirical support for non- _g_ intelligences is either lacking or
very poor. She argued that despite this, the ideas of multiple non- _g_
intelligences are very attractive to many due to the suggestion that everyone
can be smart in some way.  [51]

A critical review of MI theory argues that there is little empirical evidence
to support it:

> To date, there have been no published studies that offer evidence of the
> validity of the multiple intelligences. In 1994 Sternberg reported finding
> no empirical studies. In 2000 Allix reported finding no  empirical
>  validating studies, and at that time Gardner
> and Connell conceded that there was "little hard evidence for MI theory"
> (2000, p. 292).  [ _ citation needed   _ ]  In 2004 Sternberg and Grigerenko stated
> that there were no validating studies for multiple intelligences, and in
> 2004 Gardner asserted that he would be "delighted were such evidence to
> accrue",  [52]  and admitted that "MI theory has few enthusiasts among
> psychometricians or others of a traditional psychological background"
> because they require "psychometric or experimental evidence that allows one
> to prove the existence of the several intelligences".  [52]  [53]

The same review presents evidence to demonstrate that  cognitive neuroscience
 research does not
support the theory of multiple intelligences:

> ... the human brain is unlikely to function via Gardner's multiple
> intelligences. Taken together the evidence for the intercorrelations of
> subskills of IQ measures, the evidence for a shared set of genes associated
> with mathematics, reading, and g, and the evidence for shared and
> overlapping "what is it?" and "where is it?" neural processing pathways, and
> shared neural pathways for language, music, motor skills, and emotions
> suggest that it is unlikely that each of Gardner's intelligences could
> operate "via a different set of neural mechanisms" (1999, p. 99). Equally
> important, the evidence for the "what is it?" and "where is it?" processing
> pathways, for Kahneman's two decision-making systems, and for adapted
> cognition modules suggests that these cognitive brain specializations have
> evolved to address very specific problems in our environment. Because
> Gardner claimed that the intelligences are innate potentialities related to
> a general content area, MI theory lacks a rationale for the phylogenetic
> emergence of the intelligences.  [53]