I am new to this forum but the open question regarding the topic of the debate seems to invite alternate points of view and I definitely have information that would be considered as an alternate point of view but in my mind is nonetheless just as important as the debate itself.
The information that I refer to is fully contained in the YouTube playlist that I mention below (and I have watched all of the videos in their entirety) and this information fully makes the debate become an entirely moot point (since contact has already been made (on a many to many basis) since early in 2018). The civilisation communicating is more than 800,000 years old and comes from 444.2 Light Years away.
There is no use having a debate (scientist to scientist) ruling out all other sources of information that are not of a "scientific" source on a topic that has already become a moot point to discuss. Would the discussion/debate, not be better spent on whether the first contact (as you call it - which by the way has already happened as part of the extra-terrestrial race's project which they refer to as the "Direct Contact" project), was in fact already made and whether it is worth validating collectively or individually (through the quality of the information being provided and through the gut instinct all humans were born to use in discerning what information is useful to them) as the genuine contact that the SETI institute has been seeking (in all the wrong ways) for years?
As the ETs in question have stated in the material on the YouTube channel, the reason the SETI radio telescopes will never pick up anything as contact is due to the fact that all ET races out there have already advanced far beyond using radio wave technologies now using MUON-based quantum level technologies to communicate with each other (and are already using the human internet/WWW digital computer technology to communicate with those that have been chosen to be part of this direct contact project phase).
So if you are really of an open-enough mind to allow the "other side of the debate" into your thoughts, then I would like you to seriously consider the "third" option of this debate: That they have already contacted us and have provided pages and pages of absolutely amazing information on such topics as how they can actually travel the huge number of light-years involved from their planet to ours (i.e. 444.2K light-years in about six to seven hours in one of their mother ships or even instantaneously in a time-travelling "fighter ship" as described by them in their multiple articles relating to what they term "Supra-Luminar Travel").
Only about ten individuals on their motherships have learned to communicate in written Spanish (and in written English) and their native language is closest to that of the Native American Navajo tribes' sounds/words and sentence structure, although amongst themselves, or even to the ships onboard computer, they primarily only use telepathy (and all this information is only according to the material provided in the videos/articles on the YouTube channel). I personally have nothing to do with the material in any way (other than just being a reader/viewer of the information provided).
Human-based science has already gotten so many of their base assumptions wrong that it is hard to accept concepts that dramatically contradict the accepted mainstream concepts about such things as "What is Matter, What is Time, What is Gravity", but an open-minded individual can get the answers to all of these questions and so much more in the videos on the YouTube channel mentioned below.
So for me personally the question is not as per the "Shapley - Curtis Great Debate" as to how will the ETs communicate with us, but rather: if they did communicate with us would we just reject their communications as not being a likely source for an ET to use (i.e. the internet - which to them is such inferior technology it is easy for their quantum computers to interface to it and participate in "direct contact" in the exact way that we communicate between one another of ourselves in everyday life).
So......hopefully all that has been mentioned above and all the information presented in the Youtube channel below will be enough food for thought for all you great thinkers that we might actually start to have a debate about something that matters and is relevant in the society of today.
Here is the YouTube playlist (and I strongly suggest that you only start at the beginning of the information and watch the videos in that order specified in the playlist since each one builds on knowledge and concepts provided in the previous videos)...
https://www.youtube.com/watch?v=NOBV8Sv ... S6U6o85_ms
Alternatively you can search for the YouTube channel called "Cosmic Agency" (and if you can understand Spanish then there is an even better somewhat equivalent channel for that audience called "Agencia Cosmica").
I am nothing to do with the channels other than just a subscriber and avid follower of the information being provided.
Peace be with you and may humans accept the assistance already being provided by this group of Extra-Terrestrials.