Thanks.
That is a fundamental question. Even in western knowledge, I think we like to make claims about what is true because we peer-review and because we have this whole process, but in reality much of what is published is not going to be true. Much is disputed.
In studies of indigenous knowledge, which is based on what you heard, it can be more anecdotal and it may have importance. If we're looking at going out with people into the field and comparing, groups of people are going out, identifying plants and figuring out what they're useful for, or what birds do. Different people get together and they talk about it. They discuss it, they disagree and they settle on what the answer is.
As my colleague mentioned, it's very dynamic. It's happening now. People are making new knowledge.
I think it's very contextual to what you're dealing with and it's something that outsiders should be more sympathetic to, because we do the same thing as scientists. We come together, we peer-review and we do all this.
I hope that answers your question, to a certain extent. It would be a very long answer to get into what truth is and what knowledge is.