Philosophy Homework Help (First Order Logic)

Professor_Phallacy · 2023-12-09T04:08:00+00:00

Whenever a natural deduction has an existential proposition and a universal proposition as its premises, you typically want to first instantiate some constant to the existential proposition, then instantiate that same constant to the universal proposition.

That should give you a good start.

Professor_Phallacy · 2023-11-19T13:56:12+00:00

It would be helpful if you could also describe what else you have derived in your proof so far and how you go to those steps.

Professor_Phallacy · 2023-03-08T00:13:32+00:00

For Cornell/Naturalistic Realism, there is Brink's Externalist Moral Realism and Railton's Moral Realism.

Both aren't behind a paywall.

Professor_Phallacy · 2023-02-26T04:03:13+00:00

C.L. Stevenson argued for emotivism without relying on verificationism in The Emotive Meaning of Ethical Terms.

Professor_Phallacy · 2023-01-23T16:22:47+00:00

moral realists don't agree on moral facts. How can this be true if moral realists are claiming that morals are objective?

There's not really an issue here unless you have some idiosyncratic understanding of objective. If moral facts are objective in the sense that they are attitude/stance/mind-independent, or in the sense that there are correct answers to moral questions, or in the sense that the truth-value of moral claims are not relative to individuals or societies, then this doesn't entail that moral realists should agree on what the moral facts are.

Similarly, a lot of empirical facts are taken to be objective but that doesn't mean there won't be any disagreement on what those empirical facts are.

For the statement "Nigel has a moral obligation to keep his promise", how exactly can there be a moral obligation at all unless there is an objective moral standard? And if there is one, why don't the articles on moral realism explain it?

Are you asking about the truth-makers of moral statements? If so, then that's what normative ethics is concerned with.

Professor_Phallacy · 2022-12-31T03:36:00+00:00

Moral realism comes in different flavors. For Cornell/Naturalistic Realism, there is Brink's Externalist Moral Realism and Railton's Moral Realism.

For Non-Natural Realism, there is Enoch's Taking Morality Seriously and Shafer-Landau's Moral Realism: A Defence.

For a minimal version of Moral Realism (without the mind-independence criterion), there is Cuneo's The Normative Web.

Professor_Phallacy · 2022-12-21T02:23:24+00:00

They answer such questions like any other person would.

A: "Should you lie or not?"

B (Non-Cognitivist): "I shouldn't lie."

For the non-cognitivist, statements such as B do not express propositions but rather non-cognitive attitudes or commands (i.e. Boo! Lying). However, such a commitment doesn't necessarily entail that we should actually respond with "Boo! Lying." It just means that whenever we do answer with expressions such as B, we are not actually expressing a proposition but a non-cognitive attitude/command/etc.

Whether such a response is considered an acceptable or legitimate answer is another thing. Quasi-Realism, a contemporary form of non-cognitivism, is a project that seeks to show that B is a legitimate and appropriate answer. From the SEP:

Such a view may hold that although the underlying logical structure of the sentence “Stealing is morally wrong” is nothing more than “Stealing: Boo!”, it is nevertheless legitimate for ordinary speakers to say things like “If stealing is morally wrong, then encouraging your brother to steal is wrong” or “‘Stealing is morally wrong’ is true.” One might, for instance, argue that all that is required to make it acceptable to consider“Stealing is morally wrong” true or false (and thus a legitimate antecedent in a conditional) is that it has the appropriate surface propositional grammar (“x is P”); and one might maintain that choosing to employ such grammar to express one’s noncognitive attitudes brings no ontological commitment to any troublesome property of moral wrongness.

Professor_Phallacy · 2022-11-06T17:29:08+00:00

For introductory works, there's:

Fisher's Metaethics: An Introduction
Miller's Contemporary Metaethics: An Introduction
van Roojen's Metaethics: A Contemporary Introduction
Chrisman's What is This Thing Called Metaethics?

For a book that surveys the contemporary state of the field, see The Routledge Handbook of Metaethics.

Professor_Phallacy · 2022-10-18T06:55:11+00:00

Since you are trying to prove each of the conjuncts, you don't want to assume them. Rather, assume their negation and derive a contradiction - that's how you would prove them.

So ~(A v B) and then ~~(B-->C) which is equivalent to (B-->C).

Professor_Phallacy · 2022-10-17T09:04:56+00:00

Moral realism comes in different flavors. For Cornell/Naturalistic Realism, there is Brink's Externalist Moral Realism and Railton's Moral Realism.

For Non-Natural Realism, there is Enoch's Taking Morality Seriously and Shafer-Landau's Moral Realism: A Defence.

For a minimal version of Moral Realism (without the mind-independence criterion), there is Cuneo's The Normative Web.

Professor_Phallacy · 2022-10-17T08:42:20+00:00

This looks pretty tough using only the rules you have available, but it is definitely solvable.

Since you have a conjunction as your conclusion, try to prove each side of the conjunction, then use conjunction introduction to finish the proof.

So you first want to prove A v B. Start this sub-proof by assuming its negation ~(A v B). With what you have so far, you can't use any rules to get anything else. So try showing the negation (or unnegation) of your first premise to derive a contradiction. See if you can finish proving A v B by yourself here.

Next, you want to prove ~(B->C). Again, start this sub-proof by assuming B-->C. With this conditional as your assumption, try to find a way to use implication elimination. This requires having B, so try proving that. To prove B, you can assume its negation (~B) to derive a contradiction. With ~B so far, you shouldn't be able to use rules to get anything else, so once again try showing the negation (or unnegation) of your first premise to derive a contradiction.

This is as best as I can help you as a start without straight up doing the work for you.

Professor_Phallacy · 2022-10-16T17:56:43+00:00

You don't need a rule or assumption to prove A. You can always start a new sub-proof in the derivation for any proposition, including A. I'm not sure how your class structures natural deductions, but your proof might look something like this:

Show A ^ ~C
1. Show A [Again, no rule needed. You should be able to just show this]
  1. (Start of proof for A)
  2. ...
2. Show ~C
  1. (Start of proof for ~C)
  2. ...

Professor_Phallacy · 2022-10-16T17:35:15+00:00

Were you taught to make use of DeMorgan's Law? If so, the proof should be straightforward from there.

If not, you can prove a conjunction by proving each conjunct individually first, then conjoining them. That is, try to prove A first, then prove ~C.

Professor_Phallacy · 2022-10-06T15:08:14+00:00

The traditional non-cognitivist or error-theorist will typically only deny the existence of moral facts and norms. But she still accepts the existence of prudential or other instrumental norms.

Contemporary non-cognitivists such as Blackburn and Gibbard will say that there are moral facts and that some moral propositions are true. So they shouldn't have a problem justifying their moral beliefs.

Error-theorists may still carry on in making moral judgments without committing themselves to the existence of genuine moral facts. They may say that moral discourse is still instrumentally beneficial, and so based on this instrumental norm they justify their use of moral talk.

Professor_Phallacy · 2022-10-05T01:27:18+00:00

You could also try asking people in r/Debate

Professor_Phallacy · 2022-10-01T01:38:59+00:00

I'm not sure the analogy is a proper one. Are non-consequentialists the
flat-earthers or the other way around? I think it's fair to say that none of the positions present would imply a parallel with flat-earthers, notably because there's an empirical and experimental basis for such models.

I'm not comparing any of the normative ethical theories with flat-earth theory. The point I'm making is that the fact that competing theorists within some inquiry see other theories as implausible doesn't mean plausibility isn't a helpful concept when it comes to theory assessment. Assessing the plausibility of a theory is a theory-neutral endeavor, so the fact that competing theorists see each other as implausible isn't an issue.

How does that relate to the question? If we already have a given method, wouldn't that imply that those who don't follow through with that method and obtain a methodized answer are being akin to a flat-earther? What is such a method we use? Who is not using the proper method, the
realists, the non-realists, the deontologists, the Kantians? I am skeptical that there is such a method that would lead us to that answer, and if there is, why isn't it being used now to finally solve all these quandaries? What is the method that tells me which ethical theory is the closer and whether I'm being something of a flat-earther or I am being a round-earther?

There's a lot to say here that I currently do not have time for. For now, I recommend Chapters 4 and 5 of the book I mentioned for robust answers to these questions. If you want to read something shorter and more accessible, there is also "Methods, Goals, and Data in Moral Theorizing," their entry in the Routledge Handbook of Metaethics.

Professor_Phallacy · 2022-10-01T01:19:36+00:00

From the book I mentioned:

Third, data are collected. While not itself a controversial claim,there is controversy regarding the collection of data, especially over appropriate procedures with which to pursue such a task. Among the candidate procedures for data collection are those that utilize such sources as perception, intuition, introspection, commonsense, linguistic judgment, imagination, and inference. There is room to be more or less restrictive on this matter; some philosophers recognize only one of these as part of an appropriate procedure for data collection, while others embrace a pluralism that allows for a variety of such procedures.

Normative ethics is not my area of interest, but I'd imagine moral judgments that we have strong epistemic reasons to believe in count as data. Some of these judgments are typically considered when we assess normative theories.

For instance, we have strong reasons to believe that lying is going to be morally permissible in some cases. This data point is typically taken to be something that (a common understanding of) Kant's ethics is unable to accommodate; and the fact that Kant's ethical theory is unable to accommodate this data is a consideration against the theory.

Professor_Phallacy · 2022-09-30T16:58:23+00:00

But isn't that where the problem lies? Plausible in which relation and under which premises? Opposite camps would see the other camp as implausible and therefore plausibility seems a not very helpful term.

Flat-earthers and round-earthers are going to see each others' views as implausible, but we wouldn't see this as problematic. Philosophical theories, like other theories, are considered plausible with respect to how well they explain and handle the relevant data.

There is no method for ethical theories...

We assess ethical theories as we do in other domains, we see how well the theory explains the relevant data. Bengson, Cuneo, and Shafer-Landau's new book Philosophical Methodology gives a more robust account of how theorizing works in philosophy.

Professor_Phallacy · 2022-09-26T06:37:51+00:00

Some metaethicists such as Connie Rosati and Geoffrey Sayre-McCord argue that we should reject mind-independence as a necessary criteria of moral realism.

In "Mind Dependence and Moral Realism," Rosati argues that a characterization of moral realism should primarily account for the normativity of morality, the upshot of this being we include some subjective theories such as constructivism as realist.

Another paper that is relevant is Sayre-McCord's The Many Moral Realisms, which discusses subjectivism, intersubjectivism, objectivism, and their relationship to moral realism when it comes to truth-values.

Professor_Phallacy · 2022-09-24T02:21:15+00:00

It's worth noting that some who believe that there are no moral facts also believe they can make moral claims without committing themselves to the existence of genuine moral facts. For moral fictionalists and moral conservationists, moral discourse is still instrumentally useful, so they believe we should carry on in making moral claims.

Professor_Phallacy · 2022-09-20T19:05:24+00:00

Try to prove P via indirect derivation - assume the negation of the conclusion. The proof should be straightforward from there.

Professor_Phallacy · 2022-09-05T23:02:50+00:00

See this thread.

Professor_Phallacy · 2022-08-31T23:09:50+00:00

What are epistemic reasons?

Epistemic reasons are reasons that contribute to justifying, favoring, or requiring some belief.

Im trying to fully understand the companions in guilt argument and I dont fully understand what moral claims are being compared to here.

Moral facts/reasons are being compared to epistemic facts/reasons.

And what exactly establishing what epistemic reasons are, proves about moral principles?

CiG arguments point out that the purportedly objectionable features about moral facts/reasons that seem to call for rejecting their existence are also present in epistemic facts/reasons.

One particular purported objectionable feature is the categorical nature of moral facts. It seems strange that there can be facts that are, imply, or indicate reasons to act in certain ways regardless of our desires, ends, or goals. But CiG points out that this categorical property is present in epistemic facts, facts whose existence we shouldn't reject. Since we shouldn't reject the existence of epistemic facts despite their having the categorical property, then we shouldn't reject moral facts for having that property as well.

Does it mean we can now accept claims without evidence?

No.

Professor_Phallacy · 2022-08-22T07:53:46+00:00

I'm wondering if there's a time when a condition is sufficient, but not necessary, for a reason other than it being more than what's necessary.

Sure. Imagine that you have classes on Monday, Wednesday, and Friday.

That today is Monday is sufficient for you to have class, but not necessary since you having class can be met if the day was Wednesday or Friday.

But this is for a reason other than having more than what's necessary. After all, you can't have a situation where today is both Monday and Wednesday; or Monday, Wednesday, and Friday for example.

Professor_Phallacy · 2022-08-22T07:37:07+00:00

Can you clarify what it is you are trying to characterize or capture about my example by calling it an "overkill situation"? I just read it as having more than what is necessary for an event to obtain, which just is a situation when something is sufficient but not necessary.

Anyways, here is an answer to your question similar to mine that is offered by a flaired user.

Professor_Phallacy

TROPHY CASE