1:1 "That which" comes from the Greek word ὃ = so WHY is the word "that" not used before the three other mentions of "which", which has the same Greek word quoted here.
You mean the three times to make four "that which" is actually used? 4 times, that's strange! Maybe you could cut n paste the wotsupianity translation so we can have an idea of what you are talking about?
Does "that which" sound like a person being referenced here???
Yes, what else did the disciple's hands handle as well as their ears heard and their eyes see? John tells you if you hear and your eyes read.