Based on Bhagavad Gita Chapter 07, Text 24
The Bhagavad-gita (7.24) indicates that those impersonalists who consider Krishna’s form to be a temporary and illusory product of the impersonal Brahman are abuddhayah, bankrupt of intelligence.
The impersonalists conceive the Absolute Truth to be impersonal, devoid of any personality, quality or activity. They are classic and tragic examples of taking a good thing so far as to make it disastrously bad.
The good thing about them is that they have gained an insight into the futility of all worldly forms.They have recognized that these forms being temporary can never offer lasting pleasure but can instead cause bondage and suffering. Consequently, they conclude that such forms are products of illusion, and seek a reality beyond these forms.
The bad thing about them is that they extrapolate their insight about forms from the material realm, where it holds true, to the spiritual realm, where it doesn’t. Gita wisdom informs us that the spiritual realm is characterized by non-decaying, non-temporal forms among which Krishna’s form is the supreme reality and manifests the ultimate beauty.