I see that a lot of people use \land in LaTeX. Out of habit, I use \wedge

Me 2! Once you start using them, it is hard to go back.

Nothing.

but a fly doesnt develop a new psychological capability of consciousness and such that is absent from the larva

@@mashypotatywithgravy1398 in regards to the point i am making, what you just wrote is not relevant. just because you started with a "but" doesnt make it lead to the conclusion "so option one renders humans as something special". what you wrote is just in-itself rendering humans as very different from flys, but thats all.

On option 1: the view it is that it is "logically impossible for a human fetus to come to be a normal, adult human being" to be mistaken / absurd for at least two reasons. (1) humans would be the exception to the general biological trend that mammals survive into adulthood and (2) it would also be an exception to the general biological trend that something would perish (rather than continue to survive) by gaining a power. I'm not saying I agree with these reasons but I do think he supports his view with reasons here.

@@LogicPhilosophy my point was that calling anything "absurd" is not an argument against that thing, i do not see why you think it helps to repeat the points you literally made within the video that do not do anything but again try to establish the absurditiy. if absurdity is irrelevant, then these arguments in support of absurditiy are irrelevant. he is not "supporting his view (on the actual question at hand) with reasons", he is only supporting his view about whether a certain answer to the question is absurd. as long as he does not establish that this absurdity has any bearing on whether the view is or can be correct, this is not relevant to the question at hand. either way, regarding (1), calves also dont exist as adults (I dont know why we would necessary regard the "non-existence" of adult fetuses as them "having died", so i do not reply to the "surviving into" adulthood-phrase.) you either have to claim that an adult cow is two objects at once: an adult cow and a calve that still exists in that same body, or you go with "its not a calve anymore, the calve does not exist". regarding (2) things being exceptions to trends is a huge trend, even within biology. i do not even see the absurdity here. also, moths can fly, caterpillars cant. some animals can even change their sex, thereby both aquiring a power (to reproduce by other means) and loosing their identity as being a specimen of the sex it had before. (aka "the specimen of sex x stops to exist while a new specimen with sex y begins to exist")

@@davejacob5208 I don't follow the discussion about absurdity. I think saying something is absurd is a shorthand way of saying there are some obvious objections to it (which is why I repeated them). For (1) when Olson says that the fetus doesn't survive, he isn't saying that it still exists as an adult. He means that when the person emerges, there isn't an adult at all. There is no adult at all. For (2), I really like your point here and your examples to help illustrate the point. If I can summarize (tell me if I'm wrong): (a) many species have traits that are unusual within the genus and (b) there are many examples of entities that gain powers and cease to exist as a result of gaining said power. For (b), you'd need your example would need to be a case where the entity not merely survives but just in a different form but no longer exists as a result of gaining that new power. I like it!

@@LogicPhilosophy so far you argued as if the points you made lead to the conclusion that position 1 was absurd, now you say that the absurdity just points to these two objections - so which way is it? and why use the word "absurd" in your overview of the options, when you mean two distinct problems? all this is just to say: i stay with my point that calling something "absurd" is a very lazy and counterproductive thing to do for a professional philosopher. For (1) i did not say that "it" still exists as an adult, but that there is an adult, and to say that a person exists definitely does not mean to deny there is an adult human being present. For (2) again, i am not replying to the phrasing that includes "survival" or "death", as i think it is an unnecessary (even if very attractive) equivocation of "ceasing to exists" and "dying": while the former might by necessity imply the latter (i guess?), the latter implies something different than the former. (id say in some sence less, in some sense more) since (2) relies on questioning whether it makes sense for a being to "do x by gaining a power", i think it is unfair to put in "dying" where the x is, as x is actually "ceasing to exist", and the "dying" would then only be a (necessary) consequence of x. it is certainly not absurd for a being to by gaining a power gain a trait that leads to its death. while writing about this, i found a point that if correct is even more pressing: if a being of type g ceases to be a g, then it is not clear whether there is a point in time where the being of type g dies. one might reasonable say that to die necessitates to be (present, as yourself). but as long as there is the being of type g, it just is, and as long as it is not of type g, it isnt, but at no point in time did the being of type g go through a time where it was not of type g. so the "death" would then have to be identified with the mere difference between being(/living as yourself) and not-being(/living as yourself)-anymore, where there would not be a point in time at which that difference was "present". overall, this whole topic leads me to favour intuitions revolving around nominalism (hope i am not mistaking it for something else, what i am meaning is the stance according to which there are only very fundamental physical particles and every other type of "object" is actually just a name we give to configurations of these objects.) because all this talk about a fetus being or not being equal to "its" older version just makes me think "why not just talk about "being a fetus" as a trait of this object(configuration of particles), where the object is still present but the trait might not be present anymore?"

@@davejacob5208 Ah! I see now. I take your point and see how it can be construed as disparaging. I think I need to be better about the phrasing here! Let me try to clarify and phrase things better. I think Olson takes Option 1 is flawed since it is subject to a reductio ad absurdum (we can show it is flawed via a special kind of proof by contradiction). So, it goes something like this: - If Option 1 -> Consequence 1. Assume Option 1. Therefore consequence 1. But consequence 1 is obviously not true. Therefore, we have a contradiction where consequence 1 is true and not true at the same time. There are no true contradictions. Therefore, not Option 1. You say "it is certainly not absurd for a being to by gaining a power gain a trait that leads to its death." I translate this as you saying you deny that the argument produces the contradiction (the absurdity) or you can't say the consequence that is supposed to flow from the theory is not OBVIOUSLY wrong. Here you could say that given that there are biological instances where an entity gains a power but does not die / cease to exist / persist (not sure the right word), merely citing the fact that it would not be an instance of the general rule or trend is insufficient. He would have to further show why gaining consciousness in particular is problematic. Per the nominalist solution, your thought is that there exist only particles (or whatever physics tells us are the smallest, non-composite things) and we give names to the combinations of these things (composite things). So, there is no single property (universal) or set of properties shared by all things called fetuses. Instead, these combinations just appear similar to us. On this view, when we talk of a change from fetus to adult human, we are talking about a change in our names. All that REALLY is happening is a change to the particles and their combination. I think nominalism has its own problems but I like one aspect that motivates it. Maybe this is the same thing you like about it: The fetus and the adult human are not numerically the same (one and the same thing) since they have different properties. We talk about them as though they are the same, but they are not (strictly speaking) the same thing.

Good points here! The first is that you can do this about almost anything that is susceptible to vagueness. For example, if anything is tall, then the tallest person in the world is tall. If that person is tall, then a person 1mm shorter is tall (since that is such a small difference). Here it looks like you are advocating for a nihilistic position concerning vague objects / properties. I think generally people would say something like "there is a line between persons and non-persons even if (1) we don't know where it is, (2) we our terms don't draw a sharp line, or (3) being a person is a matter of degree". I think this is also reflected in the fact that people do think animals are persons (even though they might take them to be moral / legal persons).

@@LogicPhilosophy i wasn't arguing for either side myself, just pointing out that if the concept of a person is a real thing, and you base that off intelligence. then either humans are not people, or that most/all animals are. the latter would bring rise to a litany of legal questions surrounding farming, conservation, and animal ownership. the former would also bring rise to legal questions around slavery and murder.

I do think you could draw out implications for the abortion debate, but I think you'd have to say something like X is a metaphysical person if and only if they are an ethical person (something deserving of rights / serious moral consideration). I also think you do that with your own theory of personhood here (originality, creativity). One thing I would wonder (and I think others) about your theory is how you go about defining "originality". Like suppose I create a derivative artwork, this is "new" in a sense but is it enough to qualify as a person?

The argument attempts to prove the "psychological definition of personhood" false by hypothesizing it and proving a contradiction. That's the point. We prove an idea false by hypothesizing the idea and deducing a contradiction, as you have also done more succintly. Anyone defending "psychological personhood" would likely respond to your argument by arguing that their definition includes more than just consciousness. But that weakens their position. In any case, I agree with you that academia should use more common sense to make simpler and better arguments, especially when presenting to laymen.

@@amavect The entire concept of psychological personhood is something only an academic would think of. Only under the million layers of abstraction and theory that they operate under could anything like that make sense. Any person who lives in the real world and thinks in terms of real world scenarios would plainly see that its absurd.

@@uppishcub1617 you have created a problem with your statement, as we already know that our built in thinking process is flawed and inaccurate, hence the creation of science. science is a tool used to bypass the stupidity of built in human reasoning. by claiming that academic thinking in such ways is worthless due to not conforming to ordinary thought process, in turn discounts the value of science. meaning that by extension of your logic, all science is worthless. if you still hold this view, then stop using every single modern invention, and become an anarcho primitivist

people disagree or ignore this fact... because of abortion.

@@uppishcub1617 "Anything with a good capability to think is a person" is the position of psychological personhood. That's not millions of layers of abstraction. It's common sense. It's an answer to the generic question "what defines a person?", a question that sci-fi authors have bothered to explore. "Can robots or martians be people" is a fun question. If you disagree, then of course you won't enjoy this kind of philosophy. Academics like to push the ideas to all cases, not just daily affairs. "Crows seem to think, are they people?" Of course not, but then the academic demands a better definition of personhood (do you have a better one?). And so results in the layers of complication that you hate, but it happens for the plausible reason of making a bulletproof definition.

What specifically is problematic about it? Doesn't the argument try to examine priors by saying something like "Ok, people tend to think that what makes me the same person over time are psychological connections (I can remember what I did yesterday, I have the same intentions, etc.), but this seems to lead to certain absurd consequences, so maybe there is something wrong with this assumption."

@@LogicPhilosophy I guess it's a matter of people not knowing what they don't know. Between two adjacent points of logic there is always implicitly or explicitly a "because"; because this recursion has no end, the mind must use a heuristic based on it's own intuitive sense of scale and grasp of the problem. This leads to very smart and thoughtful people like yourself to be susceptible to "forest for the trees" types of holistic errors, at least from the point of view of people with particular vantage points over you. Put another way, since you are logically capable and motivated, you can do proper housekeeping for the elements you perceive clearly, which eliminates most errors but somewhat unintuitively leaves you with a preponderance of disagrements where the key elements are not registering for you at all, making it challenging to engage and overcome the gaps.

I think I agree. If we reason from P to Q, then there is the question concerning what justifies the step, the transition, the movement from P to Q. Let's say it is an inference rule "R" and let's say "R" is a law of logic. We might ask what justifies this law of logic? Well, as you mention, it is either an element (some fundamental ground that we perceive clearly) or a non-element and so we need to explore what justifies the law of logic. In addition, we might ask what justifies P and Q. Now, the argument in the video doesn't proceed from elements / indubitable beliefs / propositions that we perceive clearly and distinctly (intuited). But, don't you think that is a pretty strict standard to have? Like, wouldn't you say that someone can have a good argument (in some sense) without starting from absolutely indubitable premises?

@@LogicPhilosophy "In some sense" is doing a lot of lifting in that statement I ask you, is the purpose of a good argument merely to be beyond refutation, or also to invite meaningful refutation if it exists? Good arguments, then - if "good" is good only in some sense and not according to a strict standard - would be in the eye of the beholder, wouldn't they? It is true that the concept of good is felt by the mind as both an absolute, and the direction towards that absolute. In serious discussion, however, a strict understanding yields more fruit; if someone tells me that something is good, that thing must either be an absolute good, or it must somehow answer the question "good for what exactly?"

@@LogicPhilosophy Incidentally, why did you delete my response to your first reply? It seems strange, especially if you ended up agreeing with it.

I can see why there might not be an answer or that the question is incoherent, but why is it the case that it was never be formulated at all? Like, do you mean something like God created us and we are not supposed to consider this type of question?

@@LogicPhilosophy our brains are so advanced, that we consider all these questions that no organism needs an answer to to survive.

​@incitatus953 how so ? We do need to survive, if we were to evolve as a species furthur. Consider the scenario where there is substantial trauma to your brain, which begs the question how much of your brain can take changes for it to no longer be you. The identity problem in my opinion is even mor daunting and important than the subjective "hard" problem of consciousness

@@delq normally no animal needs these questions, and no animal except humans is even capable of formulating them. That's why I said that these existential questions were never meant to be formulated, because they are a direct result of our intelligence, which is too great for our own good.

@incitatus953 it sounds like you are saying that the only questions that we should ask are those that are necessary for an organism's continued survival. What @delq points out is that the question of personal identity is important for our continued survival since answering it helps us understand whether we survive certain changes. I think this is true, but don't you also think that there are some important questions that don't have directly to do with the survival of the species? Say I have a friend and I want to know whether they are happy b/c, if they are not happy, then I want to do something to help them be happy. My question is this: "is my friend happy? And, if not, what can I do to help them?" Wouldn't this be an important question that is not directly related to the survival of the species?

Thanks!

I'm not clear on your reply to the first option. If X is a fetus and Y is a human, when you say Y is replaced by X, are you saying X and Y are the numerically the same object? Or are you saying that X ceases to exist and then Y comes into being? In the second option, X does not exist as Y, correct? I like the 4D approach in that my attitude to this argument is one mentioned by others. I can exist without being a person! On this approach, I start off as a non-human fetus, when I become conscious, now I have the property of being a person, and then I lose it when I lose the capacity for consciousness. This is a position suggested by some others (early Parfit, Baker). They say that one response to this argument is that it overlooks the possibility that we could exist without being persons. I really like your defeater. If I had to rephrase what you are saying: P2 is false because the human organism does not think. There is brain activity but there is not thinking since this is essentially psychological activity! Love it!

@@LogicPhilosophy I think that theories of time work as naming conventions, defining what "numerically equal" means. My point was that I think Eric Olson hastily dismisses the first option, when there exist fine ways of describing what happens to the fetus. Namely, using the naming scheme of presentism (the human replaces the fetus, they are not the same object, the fetus doesn't "die"). I think your 4Dist view still falls to a variation of the argument. 4Dism, as I understand it, allows multiple objects to intersect in space-time. So, are you the combined fetus+adult object, or just the adult object? How do you know? What sort of test could distinguish? The argument subtly presents a challenge to develop a theory of personal identity. Your rephrase is almost there! Think along the lines of Aristotelian realism. The psychology does the thinking, but the physicality embodies the thinking. We can describe both as thinking, but not as the same kind of thinking. I am the structure embodied by this physical form. What exactly constitutes my physical form is left to empiricism and science to explore.

I think on the 4D view, you would have to say that (1) you have a temporal part that is a fetus, (2) you have a distinct, non-overlapping (or only partially overlapping) temporal part that is an adult, and (3) the adult temporal part overlaps with the person temporal part (the person temporal part is whatever is conscious). Some problems with this view: (O1) you have two distinct things (the person and the adult) that potentially overlap in the same spacetime and (O2) it doesn't really answer what you are: are you just the person part or the whole 4D object (fetus, adult, person). I think O2 is what you are pointing out in your comment, correct? You've caught me! I've never really understood Aristotelian realism. I see the words, I've read articles, but I can't wrap my head around it! Is there something you've read or come across that helped you understand it?

@@LogicPhilosophy Yes, O2 is what I'm pointing out. What! I'm surprised it doesn't for you! I picked up AR through studying finitism in the philosophy of mathematics. I'll point you to the Wikipedia page "Structuralism (Philosophy of Mathematics)", and especially the section about "ante rem", "in re", and "post rem" structuralism. If you want something more technical, "What Numbers Could Not Be" by Paul Benacerraf. Unlike Platonic realism, which describes the number 2 as existing separate from physical objects, Aristotelian realism describes the number 2 as existing if a physical object embodies the property of 2-ness (perhaps a group of 2 people). Nominalism would eliminate 2 as an object, restricting 2 to a predicate. It's all just a matter of definitions. To compare, I think all theories of time are equiconsistent, but each emphasizes a certain view of what it means to exist through time. Similarly, we can study theories of composite objects, or theories of abstract objects, and learn how each emphasizes certain aspects of existence. Choose the ones you like for your personal ontology. So, to me, asking "where is the person in this human? Is the person different from the human?" is like asking "where is the 2 in this group? Is the 2 different from the group?". I view those as higher-level objects formed by the physical structures, but not identical to the physical structures. Teasing out that difference is hard, so I'll rephrase again. A physical structure is defined by objects in a predicate relation. The abstract object is deduced to exist because of the predicate relation. I could probably go further to write some first order logic axioms to encode this.

If I had to guess, I would say most people would say that you have a moral obligation to help people in serious immediate need even if you don't have a legal obligation to do so. So, I guess, my response to you would be what reason do you have for saying these people are wrong? What fact have they overlooked or what error did they make in thinking about this belief?

Let's say you are in an argument with someone. You might say "Let's assume I'm the smartest person on the planet." In saying that, you are not asserting that this is the case, you are just throwing that proposition out there or supposing it is the case to see what might follow from it or proposing it as a hypothesis. Once you've done that, you want to show what follows from that assumption. The assumption (or subproof) is "open" in that you are actively reasoning with it.

​@@LogicPhilosophy Thank you so much. This really helped. Pls can you explain what scope of an assumption is and meaning of closed assumption? Thanks for everything.

@@oniowolabiezekiel1668 Sure. I'll try to put it plainly using a metaphor (this might complicate things though). Let's think of a proof like a box. So, you can have a box (your main proof) and put smaller boxes in that box (these would be your subproofs -- your proofs within a proof). You can think of the formulas / propositions as things you can put in a box. Now, suppose you start your proof with 3 premises. This would mean you have one box and three items in your box. The scope of this first box are all the items in the box (whether they be boxes or items in the box). Now suppose you make an assumption (so you have three premises and then an assumption). When you make an assumption, you are creating a subproof. So, you are adding a smaller box to your box. The scope of the assumption is the box you added and then anything you put in the box (so more formulas or more boxes). There are special rules that, provided certain conditions are met, you can derive a formula from a subproof (conditional introduction being one of them -> it allows you to derive a conditional). Using our metaphor, this allows us to add an item to a box one level outside of the current box we are working in. Whenever we do this, we are said to "close the assumption" or "close the subproof". In other words, we use a rule on the subproof and then we are done with the subproof.

@@LogicPhilosophy Thank you so much.

You want the Greek lowercase "xi" with an overline. I would do this in WORD by 1. Insert Equation, 2. typing \bar{} then a box will pop up and then 3a. you can insert the xi in there (probably from the symbol editor) or 3b. just type \xi. In LaTeX, it is $\bar{\xi}$. Hope this helps!

@@LogicPhilosophy Mate you are legend! Thank you so much.

You're welcome

ohhh!!! Did you pass?

@@LogicPhilosophy done well so far with the hand-ins! Got the exam in may and it’s looking good, thank you!

Totally agree. If the situation is such that precision in speech is to be expected, then saying "all Xs are Y" means each and every X (within reason). For example, if I say "every human is mortal", obviously I'm not referring to hypothetical humans.

First-rate summary here!

I really like this question, partly because (1) I wasn't sure how to answer it and (2) I don't remember why I explained it the tree decomposition this way rather than the other way. Here is my best attempt to answer it: Since we are branching not-P to the left and Q to the right, we are not placing any restrictions on Q in the left branch or P in the right branch. I interpret the branches not only in terms of what we DO write but also what we DON'T write. In each branch, the truth value of the other side of the conditional is not written. This means that its truth value assignment is irrelevant. This means that you can assign it either a value of T or F and the wff you decomposed will be true. So, if we decompose "if P then Q", in the left branch (where we have not-P), P is F and Q is T or Q is F (the 3rd and 4th rows). In the right branch (where we have Q), Q is T and P is T or F (the 1st and 3rd rows). So, to your question, how is the conditional true when both P and Q are true? To me, the answer is that there is a possible interpretation of the right branch that allows for that. Since the wff is true in two interpretations: (1) Q is T, P is T or (2) Q is T, P is F. To your second question, why can't we simply decompose "if P then Q" with two branches: one P, the other Q. To me, I interpret the branches in terms of what they say and don't say (the letters in the branch and the ones not in the branch). The left branch would contain "P" but not include "Q", so, this left branch is saying that the truth value of "Q" is irrelevant. This would mean that there are at least two interpretations that make "if P then Q" true: (1) P is T and Q is T (good!), (2) P is T and Q is F (wait! no! This is not right!).