The current definition is: "pr₁ is cognition (process of thought) with
inputs pr₂=pe₂, outputs pr₃=pe₃, passing through stages pr₄,
performed by pe₁.".

I do not understand what "pe₃" signifies. "pensi" has only two sumti
slots: the thinker (pensi1) and the thought (pensi2). There is no pensi3.

Furthermore, I think that pruce3 should be aligned with pensi2 (the output
of cognition is thought); I am not sure what the input of cognition is
(maybe senses, other thoughts, and sub-emergent neuron pulses?). I would
change the definition to be, in relevant part, "... with inputs pr₂,
outputs pr₃=pe₂, ...". I would be fine with someone filling x2 =
pruce2 here with lo selpei, but I would not suggest that that is the only
possible input nor align the sumti slots in such manner as is currently
the case.