Man is the measure of all things is an excerpt from a well-known phrase by the Greek sophist Protagoras, which expresses the notion of relativism, that each person understands something in their specific way.
The full sentence is: "Man is the measure of all things, of things that are, while they are, of things that are not, while they are not."
This sentence is based on the theory of the philosopher Heraclitus who described the incessant flow of reality, revealing that knowledge can be altered thanks to the changing circumstances of human perception.
Based on Philosophy, it is possible to establish a relationship between this phrase of Protagoras and the sophists' conception of truth. This phrase fits into the sophistic doctrines, which defend relativism and subjectivity, that is, each person builds their own truth. What is true for one person may not be true for another.
It is possible to affirm that Protagoras was the precursor of the existential relativism present in authors like Luigi Pirandello.
This phrase was opposed to the philosophy of Socrates, which defended absolute truth and truths of universal value. Socrates was very critical of the sophism, as it used rhetoric and relativism as instruments to achieve particular goals. The sophists charged their students money to teach speech techniques so that they could persuade their listeners.
This phrase is considered by many to be a sophistic maxim or axiom.
Do you know what an axiom is? Find out more on here.
Interpretation of the phrase Man is the measure of all things
A possible explanation for this sentence is that man has the power to determine the value or meaning of things, creating his own reality.
For example:
Two people live in different countries, one in Brazil and the other in Portugal. The two have to make a 500 km car journey. For the person who lives in Brazil (which is a larger country in size), 500 km may not be a long journey. However, for the person who lives in Portugal (smaller in size), 500 km can be considered a long journey.
Thus, we see that the same distance has different perceptions for the two people, that is, it can be a relative concept depending on people's reality.
