doubt+in+philosophy

Let us not pretend to doubt in philosophy what we do not doubt in our heart (Peirce)

Doubt in philosohpy: We might say it is not the real world. Nothing is real. No one has existed in the world. We might say someone is telling us we are living, which is not actually. We follow our brain, thinking we are living, which is not actually. For example: Matrix

What is philosophy is Philosophy is a way to study of general and fundamental problems concerning matters such as existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing these questions (such as mysticism or mythology) by its critical, generally systematic approach and its reliance on reasoned argument.

It is hard to understand the whole sentence, and once you understand it, it is hard to explain. We doubt philosophy because it thinks in a logical way. For example, Is God exists? We cannot answer this question, because we cannot prove it. It is beyond with our knowledge because we never see God. However, this statement is suggesting we try not to pretend to doubt it, like what we do not doubt in our heart. We believe in our hearts, because once we know it. We think it is the right thing. Therefore, we do not doubt with our hearts. According to this, the statement suggests we try not to pretend to doubt philosophy (obviously we have lots of question with it), but try to believe as we believe it in our hearts.