The first thing we are going to do is determine that the term certainty comes from Latin. Thus, when we proceed to study it in depth, we find that its etymological origin is found in the sum of two clearly differentiated Latin parts: the adjective certus, which can be translated as “precise or sure”; and the suffix – eza, which is equivalent to “quality of certain”.
The certainty is the knowledge clear and sure of something. Whoever has a certainty is convinced that he knows something without the possibility of being wrong, although certainty does not imply truth or accuracy. This means that a person can affirm that he has a certainty and, nevertheless, the information he handles is false or erroneous.
For example: “I can’t give you the certainty, but I think that next month we will be able to buy the new car”, “Carla gave me the certainty that tomorrow she will bring the money”, “I am certain that I am not making a mistake”.
It can be said that certainty is the possession of a truth that corresponds to perfect knowledge. The awareness of a certainty allows to affirm this knowledge without fear of doubt and with full confidence in the validity of the information.
The certainty, therefore, is based on evidence, or what the subject takes as irrefutable evidence. The obvious of knowledge enables the affirmation and possession of the truth.
Throughout history, many are the scholars, philosophers and thinkers in general who have addressed the certainty itself and also its similarity or its differentiation with respect to what would be opinion. Among those are, for example, classics of Greek philosophy such as Aristotle and Plato who based their ideas on pillars such as knowledge, understanding, experience and the senses.
Of course, the role played by the Frenchman René Descartes, the father of modern philosophy, should not be overlooked in the analysis of the term at hand. In his case, he gave a twist to the ideas that had been conceived in this regard so far and came to make it clear that the certainty was not based on knowledge, as had been explained, but rather on the conscience that one has that a concrete fact is true.
Kant, Russell, Karl Kopper or Gödel were other authors who also thoroughly analyzed the veracity, bringing with it the opposition of all kinds of theories about the essence, the pillars and the results that it brings with it.
The concept contrary to certainty is ignorance: if something is unknown, you cannot have any certainty. The average degree of knowledge between certainty and ignorance is doubt (the subject believes that the knowledge can be truthful but is not in a position to affirm it).
Doubt, therefore, occurs when there is insufficient knowledge to be confident about its certainty. Knowledge, in short, appears as imperfect and the person does not have absolute confidence in the truth of his propositions.