All the objects can be classified as animate and inanimate. The basis for this classification is not presence or absence of [[Atman (आत्मन्)|atman]] (soul) in specific objects. Because atma is described as vibhu (ubiquitous, i.e. present everywhere). But the presence of atman is manifested through sense organs. Therefore, presence or absence of indriya (sense organs) is taken as the base for classification of animate and inanimate objects. <blockquote>सेन्द्रियं चेतनं द्रव्यं, निरिन्द्रियमचेतनम्|| (Char. Samh. 1.1.48)<ref>Chraka Samhita ([http://www.carakasamhitaonline.com/mediawiki-1.28.2/index.php?title=Deerghanjiviteeya_Adhyaya#Sentient_and_Insentient_Dravya_.28elements.29 Sutrasthanam Adhyaya 1 Sutram 48])</ref></blockquote><blockquote>''sendriyaṁ cetanaṁ dravyaṁ, nirindriyamacetanam||''</blockquote>Sense organs here do not refer to only externally known organs like eyes, ears etc. Indriya are subtle and therefore imperceptible entities. Externally known organs like eyes, ears etc. are just their tools. E.g. plants do not exhibit external sensory organs like eyes etc., but they have all the sensations which are realized by subtle indriya present internally. It is significant to note that it was known to ancient Indian scholars, and also to Ayurvedic physicians specially, that plants do possess sensations like photosensitivity, auditory, taste, olfactory and tactile sensation i.e. all five sensations <ref><nowiki>http://www</nowiki>.[http://www.carakasamhitaonline.com/mediawiki-1.28.2/index.php?title=Deerghanjiviteeya_Adhyaya carakasamhitaonline].com/mediawiki-1.28.2/index.php?title=Deerghanjiviteeya_Adhyaya</ref>