One of the most fundamental ideas in modern evolutionary biology is that the physical structures of living organisms  can change from one kind into another through a series of small modifications. However, if there exist any significant structures in living organisms that cannot have developed in this way, then for these structures, at least, the hypothesis of evolution is ruled out, and some other explanation of their origin must be sought. Thompson notes that although Darwin admitted that he could not imagine the intermediate, transitional forms leading to many different organs, he assumed that they might later be revealed by a deeper understanding of the organ's structure and function. Nonetheless, the author considers, "while evolutionists often speak of changes in size and shape of existing organs, they still can do very little [to analyze] the origin of the organs themselves." Thompson concludes by proposing that information in texts like the Bhagavad-gita can offer "a unified description ... of an agency that accounts for the origin" of numerous complexities in "both biological form and human agency." He admits that while the process described in the Gita "differs from modern science in its method of acquiring basic information," he suggests the texts "would be worthwhile for scientists to consider" as a "direct method of obtaining knowledge." Thompson argues that "fruitful scientific investigation in this area should be possible," and that "there is reason to suppose that organized form in both the biological and cultural spheres ... originate from a transcendental source.