Are the laws of logic invented or are they independent of human reason? If they are independent, how can they exist immaterially? What does it mean for such laws to exist in a nonphysical way?

The human brain is a physical object, and many people think that logical relationships are the way they are only because our brains happen to work in a particular manner. But there’s a problem with this theory: Our brains work properly in the first place only because they recognize logical relationships—if they didn’t, we would reason incorrectly and would harvest at the wrong times, or drive in the wrong direction, or fail in our efforts to operate a computer. In that case, however, our brains’ mechanisms can’t define what counts as logic. Instead, logic helps to define what counts as a functioning brain. Since we survive only by making logically correct inferences, a correct sense of logical relationships is already part of what constitutes a viable brain, and thus it is the demands of logic, over the course of human evolution, that have shaped the physical structure of the brain, not the other way around. Another common theory is that logical relations are the way they are only in virtue of the rules...

It seems that we adopt a formal ethical theory based on our pre-theoretical ethical intuitions. Our pre-theoretical ethical intuitions seem to be the product of our upbringing, our education and the society we live in and not to be entirely consistent, since our upbringing and our education often inculcate conflicting values. So how do we decide which of our pre-theoretical ethical intuitions, if any, are right? It seems that we can only judge them in the light of other pre-theoretical ethical intuitions and how can we know that they are right? If we judge them against a formal ethical system, it seems that the only way we have to decide whether a formal ethical theory, say, consequentialism, is right is whether it is consistent with our pre-theoretical ethical intuitions, so we are going nowhere, it seems.

Perhaps I can play the devil's advocate and rebuild the case for thinking that systematic ethical theory gets us nowhere. There are actually many different systematic theories--utilitarian, contractarian, deontological, etc.--but the trouble is they clash. The defenders of such theories often agree on particular moral judgments, but as to the abstract principles that define these systems, the experts disagree. In fact, it is precisely disagreement over the principles of these systems that animates much current academic debate in ethics. Yet if not even the experts can agree on which of their systematic principles are correct and which incorrect, why should anyone else rely on them? The theories in question are just as disputable as any real moral decision they could be invoked to justify. Again, systematic ethical theories are often defended on the grounds that they are like systematic theories in empirical science. (Rawls, for example, makes this move.) Yet empirical theories in science are reliable...

If it is not immoral to shoot dead an intruder into one's house without asking questions, why would it be immoral to shoot dead an intruder into one's country?

Some folks are enamored of the idea of “shooting dead an intruder in one’s house without asking questions,” but I’m not one of them. Necessary self-defense has always been a basic part of common law, but it is quite another thing to kill a man or woman on the sole pretext that that person is an intruder, whether or not the person constitutes a genuine threat to anybody in particular. Even jurisdictions that have stand-your-ground laws, or “castle” laws, generally require that you have a genuine fear of harm, or at least a genuine fear of a serious felony, before you are justified in using deadly force. And even then, the level of force must be necessary. Stephen Maitzen is entirely right when he points out that an undocumented alien is almost certainly not a genuine and immediate threat to you. Beyond this point, however, the notion that you can lawfully kill someone just because that person has intruded into your home now circulates broadly, and it is, in fact, legally false. You have no such legal...
Law

Do you think that contempt of court through judicial discretion is unjust especially in jurisdictions that allow for jury nullification? Lawyers conduct character assassinations in the witness box all the time, and judges don't always enforce contempt rulings consistently even within the same day. I know character assassinations are something most philosophers and even some lawyers frown upon but as long as that CAN lead to uncovering the truth why not let up to twelve jurors decide for themselves--because judges either don't care or are unable to recognize this (not that they should) why does it matter what the judge thinks and why should lawyers care either? Juries decide serious cases and the role of judges in any just society is merely to enforce procedures, and even then they are not required by law to inform juries of the option of jury nullification and are not required to defend their state-protected deontic legitimacy.

Justice Joseph Story of the U.S. Supreme Court once wrote, “Every person accused as a criminal has a right to be tried according to the law of the land—the fixed law of the land, and not by the law as a jury may understand it, or choose, from wantonness or ignorance of accidental mistake, to interpret it.” Justice Story’s outlook has largely prevailed in American courts, and the standard formulation in most jurisdictions today is that though juries do indeed have a very real power to disregard (or “nullify”) a judge’s instructions in reaching a verdict, they are nevertheless duty-bound, morally, to follow those instructions, even though they cannot be punished for violating that duty. The task of a trained judiciary, according to this view, is to interpret complicated laws correctly—something that ordinary citizens are sometimes unequipped to do. The judiciary’s role also goes beyond the mere enforcement of procedures. Instead, judges must interpret complex statutes in the light of case law, and an...

What is the difference between "either A is true or A is false" and "either A is true or ~A is true?" I have an intuitive sense that they are two very different statements but I am having a hard time putting why they are different into words. Thank you.

Perhaps I could add something here too—and perhaps it will be useful: You are right that there is a difference between the two statements that you offer, and the difference has become more significant with the rise of many-valued logics in the 20th and 21st centuries. If one says, “A is either true or false,” then there are only two possible values that A can have—true or false. But if one says, “either A or not-A is true,” then there might be all sorts of values that A could have: true, false, indeterminate, probably true, slightly true, kind of true, true in Euclidean but not Riemannian geometry, and so on. The first formulation allows only one alternative to “true” (namely, “false”), but the second formulation allows many alternatives. The second formulation does indeed require that at least A or not-A be true, but it puts no further restrictions on what other values might substitute for “true.” (For example, perhaps A is true, and yet not-A is merely indeterminate.) The advantage of sticking to...

For the philosophically unsophisticated, why is it significant that logic cannot be reduced to mathematics? What difference would it have made if that project had succeeded; what is import that it failed?

Your ability to balance your checkbook, or to draw logical inferences in everyday life, won’t be affected in the least by difficulties in figuring out just how logic and higher mathematics are connected. Nevertheless, the relationship between logic and mathematics has been an intriguing conundrum for the better part of two centuries. There have been many attempts to understand various aspects of logic mathematically, and perhaps the most famous is George Boole’s Mathematical Analysis of Logic (1847), which laid the foundation for Boolean algebra. Far from being a failure, Boole’s effort seems to have been a smashing success, especially when we consider the extent to which Boolean algebra underlies modern digital computing. Nevertheless, the relationship between logic and mathematics can go in two directions, not just one, and so, just as one might try to understand various parts of logic mathematically, one can also try to understand various parts of mathematics logically. It is this further...

Is lying by omission really a form of lying?

Allen Stairs is right in suggesting that it is possible to lie by saying nothing, and perhaps it is worth adding that lies of this sort often form the basis of prosecutions for fraud. Fraud is legally complicated, but the basic idea is that you can injure someone by causing that person to rely on your assurances, even when you know that your assurances are false. Many legal systems assume that such conduct should sometimes be punished, depending on the circumstances, but they also assume that false assurances (or false representations) can come from what you don't say as much as from what you do say. For example, if I sell you a car without telling you that it has no brakes, and I omit this fact knowingly, my conduct might well be punishable as fraud. One can label such conduct with a variety of names, of course, but the basic idea is that there is something fundamentally wrong and dishonest about it, and many societies have sought to punish it. A key element in these situations is trust. If I sell...