No, the lens does not need the filter - it's for the benefit, or otherwise, of what is behind it. 
Again, my friend, you digress. Not if the filter was purchased for protection. 
“Also thinking about a clear protection filter, instead of uv. “
“I've been through 4 UV filters, two of which unquestionably saved the lens ...”
Oh and, BTW, the coffee parable was great. 
@Vetteran wrote:No, the lens does not need the filter - it's for the benefit, or otherwise, of what is behind it.
Just as a point of conversation, there are a couple of Canon lenses that require a filter to complete the weather sealing. The 50mm 1.2 L and 16-35L are two. So it could be argued that the lens does in fact need the filter.
You can argue that there is a perceivable impact to image quality, but trying to argue that a filter doesn't offer any protection to the lens is just asinine.
