Not all conclusions must be checked. If that were the case we could never act.

Every decision relies upon nearly-infinite unstated assumptions or presumptions that do not have as their basis definite knowledge.

Specifically, with the idea of babies being conscious or not conscious, if they are not conscious, then the alternative is that they are a sort of vegetative being. Which then raises the question, why not kill them?

Surely you object to that and not just on a logical level but on a deeply felt level. You know it to be wrong. Which brings me to my next point:

There ARE other ways of knowing besides logic - the greeks referred to gnosis, Dianoia, Sophia, Mathesis, Aletheia, Oida, and so on... scientific knowledge would be just one of many.)

Furthermore, in philosophy it is long acknowledged that there are truths that are beyond our capacity to know in any kind of definite or ultimate sense -- some even say that ALL knowing can NOT be definite (Münchhausen Trilemma / Agrippa's Trilemma)...

I would posit that the domain of science is not the place one can make an arugment about meaning - such as assigning something sacred value -- so it is the wrong argument to force empiricism or logical proof as the approach for this question.

You need only have a child (or even a pet, for some people) of your own to understand that such experiences of meaning are known directly, not through formal proofs. They are felt before they make it to the cognitive consciousness, where logic occurs.

I feel like I am explaining being human to robots in this thread, so I will stop here. (If you are on the spectrum or there is any other explanation for why you would not understand this already, please say so. It would relieve me of a great discord.)