Obglitatory:
Conditions have to be right in order for fossilization to occur, but besides that, there always will be gaps.
Imagine a ruler, with humans at one end & chimps at the other. At the mid-point is the fabled Missing Link. Now you have [at least] two Missing LInks:
One between humans & the former missing link, and another one between the fml & chimps.
Lather, rinse, repeat.
It is doubtful we will ever be able to ‘fill in the gaps’, so your Uncle’s arguement is fallacious, since the goalposts can always be moved.
Well, some people are, for sure.
Interesting times…
