Plato was born in Athens, Ancient Greece, in 429 BC. He was the fourth child in his family; his father was Ariston of Athens and his mother was Perictione. It is said that Plato’s family were descendants of the kings of Ancient Athens, which meant they enjoyed a certain social standing in Athens—a circumstance that enabled him to receive a high-quality education.

Plato’s real name was Aristocles, whilst ‘Plato’ was his nickname, which in Greek means ‘broad’ or ‘wide’. Some say this was due to his robust physique, whilst others attribute it to his vast knowledge and eloquent speech. Because Plato demonstrated outstanding talent in his studies and other areas, the ancient Greeks reverently referred to him as the ‘Son of Apollo’.

Legend has it that when Plato was still an infant, a bee alighted on his lips; this was regarded as a divine miracle bestowing upon him a sweet and eloquent manner of speech. There are also rumours that, in his youth, Plato took part in athletic competitions in Athens and served in the military during times of war, though neither of these claims has been verified.

Prior to 407 BC, before his encounter with Socrates, Plato had shown no particular interest in philosophy. This encounter, which took place before 407 BC, became a turning point in Plato’s life. Deeply influenced by Socrates, he began to devote himself to philosophical inquiry and became Socrates’ devoted student, studying and engaging in discussions with him for many years.

Socrates’ philosophical method—guiding people to think through questioning and dialogue—had a profound influence on Plato’s subsequent works; indeed, the majority of Plato’s writings were composed in the form of dialogues. Socrates also emphasised the importance of virtue and knowledge, a theme that is evident throughout many of Plato’s works.

In 399 BC, Socrates was sentenced to death by the Athenian authorities on charges of ‘corrupting the youth’ and ‘inducing people to worship the gods’, an event that caused Plato deep anguish and anger.

Following Socrates’ death, the 28-year-old Plato, having lost all hope in the political system of the time, decided to leave Athens and travel to other countries in search of philosophical and political knowledge. He travelled to Egypt, Italy, Sicily and Cyrenaica, amongst other places.

During his travels in Sicily, Plato attempted to apply his philosophical ideas to political practice, but ultimately failed. In 387 BC, having travelled abroad for more than a decade, Plato returned to Athens and founded an academy dedicated to philosophical discussion and research on the north-western outskirts of the city, known as the ‘Academy of Athens’ or the ‘Platonic Academy’.

At the Academy, Plato engaged in wide-ranging philosophical discussions with his students, covering numerous fields including ethics, politics and metaphysics. This Academy became one of the earliest fully organised institutions of higher learning in Western civilisation at the time, laying the foundations for subsequent higher academic institutions. The concept of the university that emerged from this also served as the prototype for the university system that arose in the West during the Middle Ages.

The Academy not only became a major centre of ancient philosophy but also provided a rich source of inspiration for subsequent academic development; indeed, the English word ‘academy’ derives from this institution. Among his students, the most famous was undoubtedly Aristotle, who studied at the Academy for as long as twenty years. The Academy existed for over 900 years until it was closed by Emperor Justinian I in 529 AD.

Until his death in 347 BC, Plato lived within the Academy he had founded. The circumstances of his death remain unclear to this day; some accounts suggest he died of old age, whilst others claim he passed away whilst travelling.

Plato’s philosophical thought spanned numerous fields, the most famous of which is his metaphysical thought.

Plato’s metaphysical dualism is sometimes referred to as Platonic realism.

It divides the world into two distinct realms: the ‘formal’ world of the intellect and the real world as we perceive it.

The world we perceive is a copy of the intelligent Forms or Ideas, but these copies are imperfect. The true Forms are perfect and unchanging, and can only be understood through the intellect; this also implies that human intellect does not include the faculties of perception or imagination.

In his work The Republic, Plato employed several metaphors to elucidate his metaphysical views; these metaphors form a complex and profound theory known as ‘the Form of the Good’ or ‘the Idea of the Good’, which is sometimes interpreted as Plato’s conception of God.

This Form is regarded as the ultimate goal of knowledge, whilst also serving as the primal force that shapes all other Forms—such as philosophical concepts, abstractions and attributes—all of which ‘derive’ from the Form of the Good.

Analogy of the Sun

The way in which the ‘Form of the Good’ shapes other forms is analogous to the way the sun illuminates or causes other objects to shine, enabling us to perceive these things in the sensible world. Plato believed that tangible things in the natural world are in a state of flux, whereas the ‘forms’ or ‘ideas’ constituting these tangible substances are eternal and unchanging.

When we speak of a ‘horse’, we are not referring to any particular horse, but rather to the concept of all horses. The meaning of this ‘horse’ exists independently of any specific, tangible horse; it is not bound by space or time and is therefore eternal. By contrast, specific, tangible horses that exist in the sensory world are ‘transient’; they die and decay.

In the metaphor of the sun, Plato describes the sun as the source of ‘enlightenment’.

He believed that the human eye differs from other organs in that it requires a source of light to see things clearly. The most powerful source of light is the sun; it is only through the sun that we can clearly discern general concepts. This metaphor can also be applied to matters of wisdom: if we attempt to explore the essence of the things around us and the ways in which they are categorised, we will fail utterly and remain utterly ignorant unless we possess the ‘form’ of reason.

The famous allegory of the cave

A group of prisoners are trapped in a cave; they are unable to turn round and can only face away from the entrance. The shadows of objects behind a fire are cast onto the white wall in front of them, so they believe these shadows to be real things. When one of them breaks free from his chains and sees the real things, he tries to tell the other prisoners, but they refuse to believe him, insisting that only the shadows on the wall are real.

This allegory conveys Plato’s view that ‘forms’ are the actual objects shining in the sunlight, whilst the world we perceive is merely the shadows on that white wall. Our sensory world is dark and monotonous compared to the vivid world of Forms. Those unfamiliar with philosophy can see only those shadows, whilst philosophers perceive external objects in the light of truth.

Divided line

We may imagine that everything in the universe represents a series of progressively greater levels of ‘Reality’. This Reality once underwent an uneven division; the resulting sub-parts then underwent a further division in exactly the same proportions as the first, and the proportions of this second division were identical.

The first division represented the separation between the world of the intellect and the world of the senses, whilst the subsequent divisions represented further distinctions within these worlds: the part representing the world of the senses was divided into that representing ‘real things’ and that representing ‘reflected shadows’; similarly, the part representing the world of the intellect was divided into that representing the universal forms and that representing ‘reflections’.

In The Republic, Plato also placed great emphasis on the importance of education. He believed that education is not merely the imparting of knowledge, but rather an excellent means of cultivating virtue and the soul, enabling people to enhance their capacity for critical thinking, comprehend the truth, and guide both the individual and society with nobler ideals. He further held that our soul is divided into three parts: reason, will and desire, emphasising that reason should govern desire, and that the aim of philosophy is to cultivate the rational part.

Plato’s philosophical thought has exerted a profound influence on Christian philosophy, medieval philosophy and modern philosophy, providing profound insights for subsequent philosophical research and reflection. At the same time, his ideas have found widespread application in literature, the arts and other fields, becoming an eternal beacon in the history of human thought.