You __cannot__ deduce the real-world probabilities from the option prices.

It may seem strange, but here is a simple example which might help you to understand.

*Suppose* that everyone in the market agrees on the real-world probabilities, and that they are not changing for any external reason.

Then _suppose_ that the investment board of a large pension fund decides that they need to increase the amount of options they have bought because they get a feeling that they would like to hold more protection against an adverse move (and since most pension funds are net long equities, this is likely to mean that they want to buy out-of-the-money equity put options to protect against a sell off in the equity market).

The pension fund will come to the dealers (investment banks probably) and will buy a whole load of put options, say. Naturally the price in the market will go up (simple law of supply/demand, and demand has increased), which implies that the implied vols will go up.

In summary: no change in the _real-world_ probabilities, but a big change in the implied volatilities which will in turn lead to a change in the implied underlying probability distribution.