Have you ever read Diogenes Laertius's satire of Pyrrho in his Life of Pyrrho? He says that he was only able to live because his less skeptical friends intervened to keep him from getting hit by carts, and falling off cliffs, and the like. It's an interesting question whether we can respond to these things—whether we can live—without adopting beliefs.

David Hume has a famous quote about this:

A Stoic or Epicurean displays principles, which may not be durable, but which have an effect on conduct and behaviour. But a Pyrrhonian cannot expect, that his philosophy will have any constant influence on the mind: or if it had, that its influence would be beneficial to society. On the contrary, he must acknowledge, if he will acknowledge anything, that all human life must perish, were his principles universally and steadily to prevail. All discourse, all action would immediately cease; and men remain in a total lethargy, till the necessities of nature, unsatisfied, put an end to their miserable existence. It is true; so fatal an event is very little to be dreaded. Nature is always too strong for principle. And though a Pyrrhonian may throw himself or others into a momentary amazement and confusion by his profound reasonings; the first and most trivial event in life will put to flight all his doubts and scruples, and leave him the same, in every point of action and speculation, with the philosophers of every other sect, or with those who never concerned themselves in any philosophical researches. When he awakes from his dream, he will be the first to join in the laugh against himself, and to confess, that all his objections are mere amusement, and can have no other tendency than to show the whimsical condition of mankind, who must act and reason and believe; though they are not able, by their most diligent enquiry, to satisfy themselves concerning the foundation of these operations, or to remove the objections, which may be raised against them. (An Enquiry Concerning Human Understanding, Sec. XII, 128)

Anyway, I'll be writing an article about this question (which was frequently raised in ancient times) and the responses to it in the not too distant future.

Anyway, I don't want to derail Miguel's thread, so if you want to continue the conversation perhaps drop me a PM and I'll start a new, skeptical thread.

Hypatia wrote:

​Back on subject, it's been a while since I read Berkeley. Is there any way that subjective idealism can account for individuality, or must it ultimately deny it? If all is mental, then what differentiates my mind from anyone else's? 

They can individuate minds from each other by assaying experiences as primitively individuated tropes, or nominalist blobs, or complexes involving bare particulars (and whatever else).