GPT has been constructed. We know how it was set-up and how it operates. (And people commenting here should be basically familiar with both hows mentioned.) No part of it does any reasoning. Taking in inputs and generating outputs is completely standard for computer programs and in no way qualifies as reasoning. People are only bringing in the idea of 'reasoning' because they either don't understand how an LLM works and have been fooled by the semblance of reasoning that this LLM produces or, more culpably, they do understand but they still falsely continue to talk about the LLM doing 'reasoning' either because they are delusional (they are fantasists) or they are working to mislead people about the machine's actual capabilities (they are fraudsters).
Then there was this experiment: https://thegradient.pub/othello/. TL;DR: they took a relatively simple GPT model and trained it on tokens corresponding to Othello moves until it started to play well. Then they probed the model and found stuff inside the neural net that seems to correspond to the state of the board; they tested it by "flipping a bit" during activation, and observed the model make a corresponding move. So it did build an inner model of the game as part of its training by inferring it from the moves it was trained on. And it uses that model to make moves according to the current state of the board - that sure sounds like reasoning to me. Given this, can you explain why you are so certain that there isn't some equivalent inside ChatGPT?
In general, I find that a lot of these arguments boil down to sophistry when the obvious meaning of the word that equally obviously describes what people see in front of them is replaced by some convoluted "actually" that doesn't serve any point other than making sure that it excludes the dreaded possibility that logical reasoning and world-modelling isn't actually all that special.
It takes inputs and produces new outputs (in the textual form of questions, in this case). That's all. It's not 'making conclusions', it's not making up hypotheses in order to 'test them'. It's not reasoning. It doesn't have a 'model of the world'. This is all a projection on your part against a machine that inputs and outputs text and whose surprising 'ability' in this context is that the text it generates plays so well on the ability of humans to self-fool themselves that its outputs are the product of 'reasoning'.