It doesn't matter how smart you are unless you stop and think.
Thomas Sowell

There is usually only a limited amount of damage that can be done by dull or stupid people. For creating a truly monumental disaster, you need people with high IQs.
Thomas Sowell

“The capacity to grasp and manipulate complex ideas is enough to define intellect but not enough to encompass intelligence, which involves combining intellect with judgment and care in selecting relevant explanatory factors and in establishing empirical tests of any theory that emerges. Intelligence minus judgment equals intellect.  Wisdom is the rarest quality of all — the ability to combine intellect, knowledge, experience, and judgment in a way to produce a coherent understanding.”

Although many intellectuals are especially well-equipped by talent and training to engage in logically structured arguments using empirical evidence to analyze contending ideas, many of their political or ideological views are promoted by verbal virtuosity and evading structured arguments and empirical evidence. Among the many arguments without arguments are claims that opposing views are “simplistic” and opposing individuals unworthy, as well as assertion of “rights” and attributing to adversaries a belief and panaceas or golden ages.

…Before an explanation can be too simple, it must first be wrong.  But often the fact that some explanation seems to simple becomes a substitute for showing that it is wrong.

The intellectuals’ exultation of “reason” often comes at the expense of experience, allowing them to have sweeping confidence about things in which they have little or no knowledge or experience.

The above 3 quotes come from Thomas Sowell in Intellectuals and Society