That would imply that a bacterium engaging in things that feel pleasant to it. After all, like me, it tries to avoid things that cause it harm and tries to do things that benefit it.
It would also imply that a Roomba is engaging in things that feel pleasant to it.
The same way I know that you are a conscious being. In other words by comparing the way they behave with the way I behave.
That would imply that a bacterium engaging in things that feel pleasant to it. After all, like me, it tries to avoid things that cause it harm and tries to do things that benefit it.
It would also imply that a Roomba is engaging in things that feel pleasant to it.
obligatory xkcd response:
http://xkcd.com/1558/