Empirically, there is small to no scientific evidence promoting the metaphysical states created by ACIM. The indisputable fact that the bodily earth can be an dream developed by our combined confidence lacks empirical help and goes counter to the vast human body of medical information accumulated through ages of observation and experimentation. While subjective activities of transcendence and religious awareness are well-documented, they cannot provide objective evidence of the non-dualistic reality that ACIM describes. More over, the course's assertion that changing one's thoughts can adjust truth in a literal feeling is reminiscent of the New Believed action and the more recent legislation of interest, equally of which have been criticized for missing clinical validity. The placebo effect and the energy of good considering are well-documented phenomena, but they don't support the great metaphysical claims created by ACIM.

Moreover, the beginnings of ACIM raise extra questions about their credibility. Helen Schucman, the psychiatrist who transcribed the class, described her experience as getting dictation from an interior voice she recognized as Jesus. This technique of channeled a course in miracles writing is not unique to ACIM and is found in some other religious and spiritual texts throughout history. The subjective character of these experiences causes it to be hard to validate their authenticity. Authorities disagree that such texts are more likely products and services of the unconscious mind as opposed to communications from a heavenly source. Schucman himself had a complicated connection with the material, supposedly experiencing significant internal struggle about their content and their sources, which brings yet another layer of ambiguity to the course's states of divine authorship.

Additionally, the language and style of ACIM are often clever and abstract, making it problematic for several readers to understand and use their teachings. The class is written in a highly stylized kind of English, with dense, graceful prose that can be demanding to interpret. That complexity can result in a wide selection of understandings, some of that might diverge significantly from the intended message. The ambiguity of the writing provides for subjective parts, which can lead to misunderstandings and misapplications of their principles. That lack of clarity may undermine the course's performance as a practical manual for spiritual growth and self-improvement.

Moreover, the commercial part of ACIM can not be overlooked. Since its book, ACIM has spawned a profitable business of books, workshops, seminars, and study groups. While economic success does not inherently eliminate the value of a spiritual training, it does raise issues concerning the prospect of exploitation. The commercialization of religious teachings can occasionally result in the prioritization of gain over authentic religious growth, with people and agencies capitalizing on the course's acceptance to advertise items and services. That active can deter from the sincerity and reliability of the teachings, spreading doubt on the motives behind their dissemination.