Extrinsic proofs add value and detail to an argument but extrinsic proofs cannot form an argument on their own. Rhetoric as we have seen is about invention which is why it makes sense that in order to utilize extrinsic proofs you must invent ways to incorporate them into the argument so that they are useful. The process or set up that is provided on page 201 is how I think most of us were taught to incorporate our supporting data for writings. When incorporating proof we have to explain how it is related to the subject of our writing, explain why it is important to the topic, and then use it to support our writings.  Without explain the relevance of the proof it isn’t useful and doesn’t provide the support we need for successful and persuasive writings. I think trusting a witness testimony is somewhat risky especially when they may be benefitting from the result that their testimony may bring. However finding a witness that is completely unbiased isn’t truly possible when they use witnesses to build up the character of someone because anyone trying to build up the character will be trying to help give a positive view and not provide any details on anything that could create a negative view, therefore the testimony is not fully revealing of the actual truth. Using this testimony as extrinsic proof is difficult. Part of extrinsic proof are common authorities and I thought it was interesting how Katy Perry is a common authority for things such a skin care products. I never really thought about how her testimony to its use was considered an extrinsic proof or that she would be a common authority. There is a difference in community authorities however, though the basic requirement to be a community authority is to be well known and respected in the community. Because Katy Perry is well known and is a part of the certain type of community that would consider using the product her testimony is valuable. It makes sense now that I’ve learned more about the use of testimony, and I understand why they also use the testimony of real people who used something like a weight loss program. But I think using their testimony is another example of untrustworthy and unbiased testimony. They are being paid to be on television and say that the product works well and they are trying to create a positive view of the product. The main thing I thought was interesting to hear and further backed up the idea of rhetoric was that extrinsic proof does not work without invention.