The deﬁnition of the word perception from the aspect of natural science may be
expressed as: physical sensation interpreted in the light of experience
(Encyclopædia Britannica - Merriam-Webster Dictionary). This deﬁnition, how-
ever, does not take into account the massive and complex structure that humans
perceive with all their senses. The deﬁnition below may be considered more gen-
eral and involves the smelling and tasting abilities, which in no sense can be con-
sidered as physical sensations, since they are based on chemical substances.