First of all, I have to explain the concept of religion and philosophy. In the religious system the main subject is God and the worship of this God. The ultimate goal for the followers of the religious community is to follow the rules of God and obtain salvation after death. Religion relies on the superhuman source and states that what it says is true and that everyone should believe in it.
When it comes to the subject of philosophy, the main goal is to understand the issues that we face in life and to understand the world that we live in. Philosophy tries to understand issues related to existence, beauty, human cognition, morality, life and death, the idea of the soul, and so on. Philosophy does not seek human happiness. Philosophers want to understand what is happening in the world, as it is being realized, and to know the world in general. Philosophy does not seek to persuade someone to believe in a set of principles (such as religion), but seeks to accept only results that are provable and reasonable. Thus, intuition and revelation have no place in philosophy in the sense that one has some kind of revelation and understands or perceives something.
Accordingly, religious certainty differs from philosophical certainty. This difference arises in part from the fact that philosophy, like religion, does not rely on revelation, a superhuman source, but is based solely on human reason and curiosity. In religion, knowledge and cognition are based on divine revelation. The basic and ultimate truths of the universe are known by revelation, not by human thought. To accept these facts does not require proof and reason, and basically, religious belief does not care about logical proof and does not seek to present its arguments. Religious texts are presented as the ultimate truth from the powerful and all-knowing God.
With the explanations provided in the above paragraphs, I believe that Buddhism cannot be classified as a religion, rather it is a philosophical system. In Buddhism we are not looking to worship God or practice our beliefs based on the word of God. Buddhism stays silent when it comes to a lot of questions, such as how this world was created, life after death, the system of judgment and accountability of our actions. On the other hand, most of the Religious teachings are based on intangible beliefs without any scientific proof. Buddhism, like other philosophical movements, is a system where people’s beliefs are based on a logical system of thought, thus Buddhism should not be classified as a religion.