Final answer:
True Socrates believed that knowledge is different from opinion because knowledge is a true belief that is backed by justification. This is reflected in the Socratic method of dialectical reasoning and Plato's JTB theory. Over time, the concept of knowledge has evolved, particularly with challenges arising in the 20th century.
Step-by-step explanation:
Socrates indeed believed there is a difference between opinion and knowledge, which is a true statement. The foundation of this belief is the idea that knowledge must not only be true but also justified, whereas opinions are beliefs that lack such justification.
For instance, one might have the opinion that it will rain tomorrow, but without meteorological evidence to support this belief, it doesn't constitute knowledge.
Socrates' approach to knowledge, which required rigorous reasoning and the ability to withstand criticism, is known as dialectical, meaning it is based on the exchange of logical arguments and it seeks to distinguish between mere beliefs and true knowledge.
Furthermore, in dialogues written by Plato, a student of Socrates, we see this distinction further refined into what is commonly referred to as the justified true belief (JTB) theory of knowledge.
Nevertheless, throughout history, this conception of knowledge has been subject to various criticisms and revisions, especially during the surge of epistemological debates in the 20th century.