Problems of philosophy

Is it possible in this world to reach knowledge that rises to a degree of certainty that no rational man would doubt? This question, which does not seem difficult at first glance, is in fact one of the most difficult things to ask. When we realize the obstacles to a correct and reliable answer (to this question), we have entered the door of studying philosophy. Philosophy is nothing but an attempt to answer such basic questions, an answer that cannot be described as a lack of care, nor can it be described at all with certainty, as we do in ordinary life and as we do in the sciences. Rather, it is based on criticism after revealing everything that makes such questions confusing, and after examining all the ambiguity and confusion that surrounds our ordinary ideas.
In our daily lives, we assume many things to be true. However, upon closer examination, we find that it is full of apparent contradictions, so that it becomes difficult for us to be guided in knowing what we can believe to be true, except after a great deal of thought.
Bertrand Russell