Perhaps as a start, you might look at the relevant entries in the Stanford Encyclopedia of Philosophy on Galileo and on Copernicus .

I am now typing. My brain isn't typing. Nor are the tips of my fingers, though I am typing by having them strike the keyboard. I am typing. You ask who this "I" is if not my brain. It's me, Alexander George. If this is acceptable, then we (you and I) can turn to decisions.

Also, take a look at Question 1161 .

You might also look at Question 997 and other entries mentioned there.

Philosophers often think of the philosophy of science as being less of a descriptive enterprise than is either the history or the sociology of science. The philosophy of science, it is often said, concerns itself in part with an evaluation of scientific practice. For instance, a philosopher of science does not just want to know what scientists have, as a matter of fact, accepted as good explanations; scientists might, after all, have jointly succumbed to some widespread error. Rather, the philosopher of science wants to know what would really constitute a good explanation—where it is assumed that scientists might on some occasions have taken something to be an explanation which was not. The philosophical project is thus in some sense a normative one, namely to determine what the scientist should take an explanation to be. Likewise, to consider another example, the philosopher of science is not particularly interested in whether scientists do believe ...

You might look at Questions 241 and 266 .

You might look at Questions 391 and 517 .

(1) does make a claim about the world. It could be true or false, depending on whether Jill is ill or not. (2) does not assert anything about the world: it does not tell us whether the state of Jill's being ill obtains, or whether it's a state the speaker hopes will not obtain, or believes obtained in the past, or is one the speaker is commanding that you stop from obtaining, etc. Both (3) and (4), like (1), express propositions. "To notice," like other perceptual verbs (e.g., "to observe"), can grammatically take either an embedded clause or a noun phrase. Thus one can observe that the puppet is on fire, but one can also observe the puppet's expression. To my ear, by the way, (4) sounds slightly infelicitous. I can notice Jill's sweating, as her sweating is something observable. But the state of her being ill isn't really observable (though manifestations of that state may be), so there's something odd, again to my ear, in claiming to notice such a state.

For a related question, see here .

I'm inclined to say No. Not because I think that happiness can only be experienced in contrast to unhappiness. But because I think that something that had never experienced unhappiness simply wouldn't be the kind of thing that could experience happiness (or perhaps even experience much of anything). We are happy when we feel comfortable, when our desires are satisfied, when things are going right. Where comfort is an option, discomfort is too; where satisfaction can be attained, frustration can too; where there's such a thing as a right way for things to go, there's a wrong way too. With the possibility of happiness comes the possibility of unhappiness. So, it's hard for me even to imagine a real being that had never been unhappy without thereby imagining a being that lacked the capacity for happiness (or even lacked any inner life).