Constructs which mistake the head as superior to the heart or as an adequate starting place for imaginings will always lead to destruction since the head can not handle nor is it designed for the necessary embedding and recursion which is a seed bearing fruit in itself. But it is sure that, before the brain breaks down and eventually falls/fails, those who mistake it as the best foundation will inevitably turn to mocking them who follow through with flow of spirit through and back to the heart. (see Lehi's Dream 1 Nephi 8:26-27 and Nephi's visitation of the same dream in 1 Nephi 11:35-36)

This phrase,"foolish imaginations" can and ought to be read as the "FULLish imaginations of his heart." In earlier verses we see that a FULL rendering of Lehi's heart brought about fulfillment on several levels already. This "fulfillment" even took the immediate form of a "filament" (pillar of light which struck a rock in front of Lehi just as the communication struck his heart with overpowering energy). The electrical charging effects of Full Imagining can be transmitted beyond the individual and others can be made to feel these effects, however, unless they are allowed to take hold in the heart where embedding and recursion can take place, then they are short lived and sometimes can have disastrous overall effect upon others who rely on second-hand spirit and external motivation. (see 1 Nephi 3:28-31 and 1 Nephi 17:53-54)