There's a lot of assumptions in saying it's just meaningless chemicals

• That chemicals are meaningless and lacking intriniic value. Seen from the outside they may appear that way, but evidently from the inside it seems quite different.
• "We" are not some other unseen brain behavior (not a crazy idea since we've never seen consciousness working in the brain)
• We are within the brain
• The brain exists at all
• Any knowledge exists at all (dubious as Mickey points out)