Consciousness and self-awareness are a distraction.
Consider that for the exact same prompt and instructions, small variations in wording or spelling change its output significantly. If it thought and reasoned, it would know to ignore those and focus on the variables and input at hand to produce deterministic and consistent output. However, it only computes in terms of tokens, so when a token changes, the probability of what a correct response would look like changes, so it adapts.
It does not actually add 1+2 when you ask it to do so. it does not distinguish 1 from 2 as discrete units in an addition operation. but it uses descriptions of the operation to approximate a result. and even for something so simple, some phrasings and wordings might not result in 3 as a result.