Many biologists still believe in a sort of post-Cartesian foundation of reality wherein objects are independent of subjects which cognize them. Recent research in behaviour, cognition, and psychology, however, provides plenty of evidence to the effect that the perception of an object differs depending on the kind of animal observer, and also its personality, hormonal, and sensorial set-up etc. In the following, I argue that exposed surfaces of organisms interact with other organisms’ perception to form semiautonomous relational entities called semantic (...) organs, which participate in biological reality as discrete heritable evolutionary units. The inner dimensions and potentialities of an organism can enter the senses of another living being when effectively expressed on the outer surfaces of the former and meaningfully perceived by the latter. Semantic organs have three basic sources of variability: intrinsic, i.e., genetic, epigenetic, and developmental processes; extrinsic, meaning the biotic and abiotic environmental conditions which affect the developmental generators of intrinsic variability; and perceptual, stemming from differences in the subject-specific interpretation of a SO’s structural basis. Extrinsic and intrinsic sources of variability are, however, just precursors to semantic organs. SOs are relational entities which always come into existence through an act of perception and their actual form depends both on the physical potentialities of the bearer and the species- or group-specific interpretation of the receiver. (shrink)