The debater uses reason and logic to examine a claim. People can say whatever they want, but the debater asks, Why? Why is what your saying actually the case?
The scientist wants evidence and supporting facts for your claim. They want to see a real life example, some data that actually support your claim. You can be skilled at reason and logic, but if reality doesn't match up with your claims, the scientist rejects it as false.
The yogin is a practitioner. It is a lived experience. They have first-hand experience, a testimony to share and a legacy to pass on.
You need to wear all three hats.
If you only wear the yogins hat, you may have profound life experiences and a great deal of certainty, but doubt can easily creep in when people question your experience. They can expose potential flaws or different views which may create uncertainty and doubt in your own experience. When you doubt your own experience, you essentially have nothing, so the yogin needs the debater and scientist hats to eliminate and manage doubt and also to analyze the validity of their experience.
If you only wear the scientist hat your understanding is limited to an objective frame of reference. The scientist by necessity really needs to also wear the debater hat, but without the yogin's hat they are always somewhat removed or distant from their subject matter. They don't allow their subject matter to change them, it remains an object of knowledge and a concept.
The debater may also wear the yogin's hat, but without the scientist's hat they risk falling to the extreme of a televangelist. The debater can formulate concrete proofs and use a wide range of logical reasoning to support their position and indeed a deep heartfelt experience, but if they are not open to the scientist's view they may be fighting for the side of ignorance. When reality and the facts don't match up to your view, sometimes it is your view that needs changing not the tone of your voice.
When you wear all three hats you have a complete practice. You really have something worth sharing. You not only know the practice, you know why the practice is important and what effect it has. You know where the potential sources of error and problems lie, you know how to approach failure and mistakes. You know what is authentic, and what is not.
With all three hats, you develop certainty and confidence. With certainty and confidence, you fulfill your own aims and you can truly act for the aims of others.