How does one "defend a thesis" without claiming your point of view to be the truth?When you talk about anyone stating something as fact, what is your source? If you don't read the books they publish then you are reading an article published by a 3rd person, not the scientists direct words. Things do get distorted in this process.
If a theory is stated as such up front, then it is OK to talk about it as fact presenting it. Semantically it is a lot easier to write in this approach. It doesn't not keep critics and skeptics from bringing up questions and pointing out flaws. With Phds people have to defend their thesis as part of the process.
There are certain truths that are still argued by people with a different agenda. I am certain that the earth is round. I am certain the earth orbits the sun. I am fairly certain E=MC², the Earth is many Billions of years old, and evolution and DNA exist.. I do not confuse science with religion.
True, few would argue accepted truths like the age of the Earth,oops, no, there are even people who argue that point, aren't there. Would you list the big bang theory (Primordial Atom) as a truth? Have you not heard others who claim it is true? If the Pope signs off on it does that make it true if you are a Catholic?
Is your religious beliefs truths?