As every bookie knows instinctively, a number such as reliability - a qualitative rather than a quantitative measure - is needed to make the valuation of information practically useful.
If quantum communication and quantum computation are to flourish, a new information theory will have to be developed.
If you don't understand something, break it apart; reduce it to its components. Since they are simpler than the whole, you have a much better chance of understanding them; and when you have succeeded in doing that, put the whole thing back together again.
Underneath the shifting appearances of the world as perceived by our unreliable senses, is there, or is there not, a bedrock of objective reality?
Numbers instill a feeling for the lie of the land, and furnish grist for the mathematical mill that is the physicist's principal tool.