It's a difficult idea to put into words, but I'll try to elaborate on what I mean.
There are many things which respond to stimuli that most people wouldn't consider "conscious". When you press the gas pedal on your car, the car goes faster, for example. The means by which the stimuli causes a response is entirely mechanical here (the gas pedal causes more fuel to be injected into the engine, causing more energy to be released when it combusts, etc).
Most people don't think of the car as "feeling" that the gas pedal was pushed, because it's a machine. It's a bunch of parts connected in such a way that they happen to function together as a vehicle. If the car could feel, would a pressed gas pedal feel painful? Wood it feel good or satisfying?
There are also times when people are unconscious, yet still respond to stimuli. For example, what does it feel like when you are in deep sleep at night and you aren't dreaming? Well, it doesn't really feel like anything; your "conscious" self sort of fades out as you fall asleep and then it jumps forward to when you wake up. But if while you're asleep someone sneaks into your room and slaps you, you wake up right away (unconscious response to stimuli).
The philosophy of mind has been debating this for decades. Google "Mary's Room" and "p-zombies". There are people out there who truly think these thought experiments prove the existence of non-physical facts, and that our subjective experience is a direct perception of this reality.
