"But that "knowledge," which clings to one single effect, as if it were the whole, without reason, without foundation in truth, and narrow, that is declared to be TAMASIC (Dull)."
yat tu krtsnawat ekasmin kArye saktam ahaitukam atatwArthawat alpam cha tat tAmsam udAhrtam ||18.22||
An intellect that has got fumed under the dulling effects of extreme Tamas clings to one single "effect" as though it were the whole, never inquiring into its "cause." The "knowledge" of the dull is painted here as that belonging to the lowest type of spiritual seekers. They are generally fanatic in their faith and in their devotion, in their views and values in life. They never enquire into, and try to discover, the cause of things and happenings; they are unreasonable (ahaitukam). (Sankara comments upon this word and declares it to mean "NOT FOUNDED ON REASON." The knowledge of the dull recognises only the effects, but ignores their unavoidable causes.).
Looking through such a confused intellect loaded with fixed ideas, the dull not only fail to see things as they are, but invariably project their own ideas upon the world and judge it all wrongly. In fact, a man of Tamasic intellect views the world as if it is meant for him and his pleasures alone. He totally ignores the Divine Presence, the Infinite Consciousness. The "knowledge" of the dull is thus circumscribed by its own concept of self-importance, and thus its vision becomes narrow (alpam) and limited. ||15||