One can never be certain.
You might need to unpack that a little bit. What specifically are you talking about that we cannot be certain?
But if reasoning is not valid
Remember that I am not suggesting it is invalid. Only that it a presumed validity not a reasoned one.
if logic is not reliable
Again I not suggesting it is not reliable. Only that it is a presumed reliability - not a reasoned one.
if science is based on an illusion and
Some might argue this - but not me. but science is also a methodology not concrete.
every theory we possess is actually wrong
Theories are theories - some are right and some are wrong.
then we don't know anything at all
The point I am making is about reasoning. Even your train of thought here require an axiom of reason to be presumed to be coherent.
and I still reject your claims except in this scenario there is no way for you to demonstrate your claim.
You can do whatever you want. You might reject or accept; but what is important is that you must concede that your rejection is not based upon valid reasoning. It is therefore just your conjecture - intuition - or whatever you want to call it.