# How do we justify our knowledge of the external world? Knowledge of the external world seems to be fallible in any case if we put the threshold of success at the highest level, namely 100% certainty. But this still raises a question: if we want to avoid complete skepticism, how can we be certain that our knowledge is at least likely to be true? In order to create a probability about the validity of our knowledge of the external world we need to start from perception. The problem is that we can be certain of the existence of perception but not the source of it (the matrix/the real world), and that is essential for the knowledge of the external world. In order to calculate our probability we then need the number of possible events E and the one favourable event F we're looking for: E = 2 possible events are external source or non-external source (matrix, hallucination, dream etc.) F = 1 favourable event i.e. external source P(F) = F/E = 1/2 = 50% It seems to me that both possibilities are equally likely....

### Setting external world

Setting external world skepticism aside for a moment, suppose I'm about to roll a die. Now there are two possibilities: it will come up 1 or it won't. If I reason as you did, I will conclude that the probability is 1/2 that the die will come up 1. Something has gone wrong here. For one thing, we can't get the answers to probability questions just by counting. There are many ways to slice up the space of possibilities, and if we use your rule, the answer we get will depend on how we do the slicing. This is a well-known problem, and there is no simple fix. But there's another problem: the probabilities here aren't chances. They are degrees of belief. Even if we thought (though we shouldn't) that the right way to slice things up is that our experience has an external source or it doesn't, without adding nothing more fine-grained, we don't have to agree that the two possibilities are equally probable. You say "it seems to me that both possibilities are equally likely." It's worth wondering whether you...

# An inventor creates a life-saving drug for disease X, which has no other cure. Worldwide, death by disease X among white people has been eliminated because of his drug; however, the death rate remains at pre-drug levels among non-whites because he has contractually restricted its sale and use to white people. For non-whites who die from disease X, is this inventor a causal factor in their death? My friend and I have debated this. I argue YES. The actions the inventor has taken to restrict the sale of his drug demonstrate intent with full knowledge of the consequences of the actions he has taken. I think his actions are not only causal, but in a world where this medicine is readily available everywhere, he becomes the primary cause of death. My friend argues NO. The inventor has done nothing with respect to non-whites. There is no causal relationship. Pulling a man from a burning building saves a life, but not doing so doesn't cause a death. Where I see actions that cause harm, my friend sees...

### As you've described the case,

As you've described the case, there's something the inventor could do that would save lives. There's also a dispute about how to analyze the notion of a cause. Some would say (your friend apparently is in this camp) that absences—in the case, not doing something—can't be causes. Others disagree and provide accounts that allow absences to be causal. This is an abstract and complicated issue, but how much difference will it make to how we judge the inventor? Suppose I'm in a war zone and happen to know that there's an IED in a certain spot. I see someone running on a path that will take him over the IED and almost certainly leave him dead. Let's assume I even know who it is and know that in all relevant respects, he's an innocent. As it happens, I'm behind a barrier, but I could easily warn him. I don't. He runs over the IED and dies in the blast. Is there something I could have done that would have saved him? We've already said yes. Would it have come at any significant cost? We can stipulate for...

# I am just starting to study philosophy and I am not understanding the claim that all knowlege comes from science. Could you please give me some practical examples?

### The reason you feel you don't

The reason you feel you don't understand the claim is because it's nonsense. I know that there are three pillows on the bed behind me, but no science was committed in finding that out. I just turned around, looked and counted. I know that I had dinner with friends yesterday. No scienceing there either. I just remember. I know that one of our neighbors recently quit a committee he'd been a member of. Once again, no science; someone in a position to know told me. In fact, it's safe to say that by far most of what we know we know without anyone doing science. Of course people doing science make observations, consult their memories and get information from other people. But so does everyone, and most of us are not scientists and don't do science. The fact that X has important things in common with Y doesn't make X a Y.

# I have recently heard that, according to physics, you can never actually touch anything. This seems clearly false and I feel it should be refuted with philosophy (if not physics). Can you comment on this? p.s. See for example https://futurism.com/why-you-can-never-actually-touch-anything which seems to claim that, according to physics, you can never actually touch anything

### According to the internet,

According to the internet, the sun rose at 6:02 this morning in Washington. I was awake and when I got around to opening the blinds I could see that the sky was blue. The sheets on the bed are blue too, though not the same blue. They're a few years old and I like the way they feel when I touch them. But the sun doesn't rise, does it? Although centuries ago, people thought it did, they were just wrong. And there isn't really a sky—no dome or roof or thing of any sort. There are sheets, but they're made of atoms, which aren't colored, nor are collections of them. And touching the sheets; don't get me started on that. Except… If someone says the sky is blue, they've said nothing false, nothing wrong. Same goes for telling you the color of their sheets; likewise for telling you they touched them. People may be mistaken about what being a blue sheet amounts to, or a blue sky, or about what's going on under the covers, so to speak, when we touch a sheet, or anything else. But that doesn't make the...

# Hello philosophers in a recent debate I was involved in a theist stated “For morality to be objective, moral propositions such as "Killing is bad","Stealing is bad", etc... need to be true independently of the person who is stating them. “ I countered “That is the way this position is normally put but a problem arises as in if there are objective moral facts how would we know this to be the fact? To know something is an objective moral fact only needs an agent to know this , how can a moral fact be known independent of a human mind to decide?” Is my position logically sound or are there problems with my reply?

### I think your counterargument

I think your counterargument is conflating issues that need to be kept distinct. Your interlocutor ((I'll call him or her your friend) said, correctly, that if morality is objective, the truth of moral claims doesn't depend on the person who makes them. That seems fine. To say that something is objectively true is to say that it's true whether or not anyone believes it. Your response was to ask how we could know that there are objective moral facts, if there really are. But that's a separate issue, and in fact it has nothing in particular to do with moral claims. If there are objective facts about what's going on now (say, in the Earth's frame of reference) in some remote part of the universe, then those facts are facts whether or not we could ever be in a position to know them. Whether X is mind-independently true and whether anyone is in a position to know that X is true are different matters. You ask: "how can a moral fact be known independent of a human mind to decide?" That's...

# In what extent through the philosophy of time, can it be said that there is no 'past' or 'future.' But that there is a only a eternal 'Now' and if that's the case, how should a philosopher or someone like me be able to explain this idea? Also if there is a eternal 'Now,' then could it be said that the Universe is only, and always present with no future or past.

### Here is a sampling of views

Here is a sampling of views on time that you'll find in recent literature: Presentism: Only the present moment is real; neither the past nor the future exist. Among other things, this view is supposed to help make sense of our sense that time really passes, but it does that (to the extent that it does) by treating the present as an infinitely thin slice and not as something eternal.On the contrary: the present is utterly evanescent. The Block Universe: On this view, all events exist eternally, as it were. That includes all events before my writing this post, all events simultaneous (in some frame of reference) with my writing, and all events after my writing. This view is claimed to fit best with the understanding of time that Relativity provides, but there is no eternal now . "Now" has no metaphysical interest whatsoever. "Now" is like "here": it's what is sometimes called an indexical term, picking out what it picks out only relative to its use. When you say "I am here" and I say "I am...

# Can philosophy make you go crazy? If you think too much about philosophy, will you end up not being able to think properly?

### If you obsess too much about

If you obsess too much about more or less anything, it can be bad for you, but some of the topics that philosophy deals with can be more troublesome for some people. I have in mind especially some forms of radical skepticism. I have met people who've been obsessed with the possibility that they don't really know that there's an external world, or that there are other people. I've had them in my office, clearly distressed. I'd guess that there were already some underlying problems. I'd guess that it wasn't a case of someone who was otherwise fully functioning and then happened on Descartes' Meditations , but the skeptical questions provided something for their background issues to latch onto. When I'm talking with such folk, I tend to stress two things. The first is philosophical: the fact that something is possible in some rarified sense isn't a reason for thinking it's at all likely. Yes: in some sense of "could," it could be that what's going on in my mind is all there is. But in this sense of ...

# how would i use natural deduction to prove this argument to be correct? Its always either night or day.There'd only be a full moon if it were night-time. So,since it's daytime,there's no full moon right now. i have also formalized the argument using truth functional logic i'm not sure if it is completely correct though and would much appreciate the help. symbolization key: N: night D: day Fm: full moon Nt: night time Dt: day time ((N V D) , (Fm → Nt) , (Dt → ¬Fm))

### There's a problem with your

There's a problem with your symbolization. The word "since" isn't a conditional. It's more like a conjunction, but better yet, we can treat it as simply giving us another premise. So in a slightly modified version of your notation, the argument would be N v D F → N D ∴ ¬F But from the premises as given, the conclusion won't be derivable. The reason is simple. You are assuming that if it's day it's not night and vice-versa. That may be part of the meaning of the words, but the symbols 'N' and 'D' aren't enough to capture it. The easiest fix is to treat "day" as "not night." That gives us N v ¬N F → N ¬N ∴ ¬F In this case, the first premise is a tautology and not needed. The argument is just a case of Modus Tollens. If you want something less trivial, you can drop the first premise and add a premise like this: D ↔ ¬N F → N D ∴ ¬F The first premise amounts to making the "v" exclusive. From there it's easy to complete a proof. A couple of extra comments. First, in the English version, you add a...

# By what definition, and extent, and to what purpose do we as humans classify the idea and act of murder as evil? To most people I ask this question seems ludicrous and the answer alarmingly obvious, but I have yet to understand why we identify this occurrence as ‘evil.’ I can understand that the intent of murder and its outcome can result in a way that selfishly benefits the murderer at such a terrible cost, and I can understand that the action of taking someone’s life is just as cruel to the deceased as it is to the people that knew and loved that victim, but it seems hypocritical to me that we as a society generalize the idea of killing as evil when relatively many of us favor capital punishment, strong military, and, at least in fiction, vigilante justice. We send men and women to violent battlefields yet, before they leave, indoctrinate the poor souls into thinking that the very act of murder is evil just by itself. They come back scarred because of this. ‘Do unto others as you would have them do unto...

### Unless you think that all

Well, we think that murder is wrong, and that it's often (usually?) not just wrong but very wrong—wrong enough to count as evil. Robbing someone of their purse is bad; robbing them of the life is worse. What you say you don't understand is why we count murder as (typically? often? almost always?) evil in spite of the fact that we think killing isn't always wrong. You see some sort of hypocrisy here. But why? After all: not all killing is wrong. The obvious example: killing in self-defense, which I hope we can agree is morally acceptable in a way that murder isn't. Even more so: killing by a police officer to protect the life of an innocent person threatened by an assailant. Capital punishment is a harder case. I think it's wrong, but I don't think people who believe otherwise are therefore morally blind. War is complicated business, but there's a case to be made that going to war is at least sometimes morally acceptable too. The place where what you're saying seems to miss the mark is here: it...

# Why are non-material objects not causally efficacious? Or, why can’t non-material objects partake in causality? Is there a reason other than simply saying that non-material objects are as such by definition? Thank you!

### The first point is that not

The first point is that not everyone would accept the presupposition of your question. Most obviously, theists wouldn't. According to many varieties of theism, the First Cause of the material world is not a material thing. Needless to say, not everyone agrees. But you can deny that there is a non-physical First Cause without denying that the very idea is incoherent. There are homelier examples. On at least some views, the fact that something was absent can be a cause. Absences, however, aren't material objects. (In fairness, they aren't non-material objects either.) So the first point is that it isn't simply agreed by the parties to the dispute that only material objects are causally efficacious. We could also add that even among materialists, broadly understood, most would say that events rather than objects are what do the causing, but it's at least arguable that events are in space and time and so even if they aren't material objects , they're physical in a broader sense. The...