Human psyche

In psychology, the psyche /ˈsaɪki/ is the totality of the human mind, conscious and unconscious. Psychology is the scientific or objective study of the psyche. The word has a long history of use in psychology and philosophy, dating back to ancient times, and represents one of the fundamental concepts for understanding human nature from a scientific point of view. The English word soul is sometimes used synonymously, especially in older texts.

The basic meaning of the Greek word ψυχή (psūkhē) was "life" in the sense of "breath", formed from the verb ψύχω (psukhō, "to blow"). Derived meanings included "spirit", "soul", "ghost", and ultimately "self" in the sense of "conscious personality" or "psyche". Interestingly, associating "spirit" and "breath" is not unique to Greek or western cultures. The Chinese character for "spirit", "soul" is 魂(hύn, simplified) which is the merging of 云(yύn) and 鬼(guǐ). 云 is commonly used as "clouds" but also as "breath" in expressions such as 吞云吐雾(smoking or vaping). 鬼 is simply "ghost" or "spirit". The linkage between "spirit" and "breath" were formed by ancient people, who at the time did not have any real contact with one another.

The idea of the psyche is central to the philosophy of Plato. In his Phaedo, Plato has Socrates give four arguments for the immortality of the soul and life after death following the separation of the soul from the body. Plato's Socrates also states that after death the Psyche is better able to achieve wisdom and experience the Platonic forms since it is unhindered by the body.

The Greek philosopher Aristotle wrote an influential treatise on the psyche, called in Greek Περὶ Ψυχῆς (Perì Psūchês), in Latin De Anima and in English On the Soul. Aristotle's theory of the "three souls (psyches)" (vegetal, animal, and rational) would rule the field of psychology until the 19th century. Prior to Aristotle, a number of Greek writings used the term psyche in a less precise sense. In late antiquity, Galenic medicine developed the idea of three "spirits" (pneuma) corresponding to Aristotle's three souls. The pneuma psychikon corresponded to the rational soul. The other two pneuma were the pneuma physicon and the pneuma zoticon.

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