How long should you keep dogs off a fertilized lawn

Dogs should never be allowed on a fertilized lawn. Fertilizers can cause lawn grass to become brittle and may cause the lawn to die.

1. The Problems of Personal Identity There is no single problem of personal identity, but rather a wide range of questions that are at best loosely connectedDiscussions in this area do not always make it clear which one is at stake, but here are a few examples:

Outside of philosophy, 'personal identity' usually refers to properties to which we feel a special sense of attachment or ownership; in this sense, someone's personal identity consists of those properties she takes to "define her as a person" or "make her the person she is," and which distinguish her from others.(The precise meaning of these phrases is difficult to pin down.) To have an "identity crisis" is to become unsure of what one's most distinguishing characteristics are—of what sort of person one is in some deep and fundamental sense. This "personal identity" contrasts with ethnic or national identity, which consists roughly of the ethnic group or nation to which one considers oneself to belong and the importance one places on this. Outside of philosophy, ‘personal identity’ usually refers to properties to which we feel a special sense of attachment or ownership. Someone’s personal identity in this sense consists of those properties she takes to “define her as a person” or “make her the person she is”, and which distinguish her from others. (The precise meaning of these phrases is hard to pin down.) To have an “identity crisis” is to become unsure of what one’s most characteristic properties are—of what sort of person, in some deep and fundamental sense, one is. This “personal identity” contrasts with ethnic or national identity, which consists roughly of the ethnic group or nation one takes oneself to belong to and the importance one attaches to this.

One’s personal identity in this sense is contingent and temporary: the way I define myself as a person might have been different, and can vary from one time to another. It could happen that being a philosopher and a parent belong to my identity, but not being a man and living in Yorkshire, while someone else has the same four properties but feels differently towards them, so that being a man and living in Yorkshire belong to his identity but not being a philosopher or a parentAnd all of these attitudes are subject to change.

Depending on how the term is defined, a property may also belong to someone's "identity" without her actually having it: if I become convinced that I am Napoleon, being an emperor may be one of the properties central to how I define myself, and thus an element of my identity, even if my belief is false.

In this sense, the Who am I? question—also known as the characterization question (Schechtman 1996: 1)—determines someone's personal identity (Glover 1988: part 2, Ludwig 1997).

Personhood. What is it to be a person, as opposed to a nonperson? What do we people have that nonpeople don't? More specifically, we can ask when a person emerges from a fertilized egg, or what it would take for a chimp, a Martian, or an electronic computer to be a person, if they could ever be.The most common answer is that to be a person at a time is to have certain special mental properties then (e.g.Baker (2000), Chapter 3Others propose a less direct relationship between personhood and mental properties, such as the ability to acquire those properties (Chisholm 1976: 136f.) or belonging to a kind whose members typically have them when healthy and mature (Wiggins 1980: ch. 6). What is it to be a person, as opposed to a nonperson? What have we people got that nonpeople haven’t got? More specifically, we can ask at what point in our development from a fertilized egg there comes to be a person, or what it would take for a chimpanzee or a Martian or an electronic computer to be a person, if they could ever be. An ideal account of personhood would be a definition of the word person, taking the form ‘Necessarily, x is a person at time t if and only if … x … t …’, with the blanks appropriately filled in. The most common answer is that to be a person at a time is to have certain special mental properties then (e.g. Baker 2000: ch. 3). Others propose a less direct connection between personhood and mental properties: for example that to be a person is be capable of acquiring those properties (Chisholm 1976: 136f.), or to belong to a kind whose members typically have them when healthy and mature (Wiggins 1980: ch. 6).

Persistence. What does it take for a person to persist from one time to the next—to continue existing rather than cease to exist? What kinds of adventures are possible for you to survive, in the broadest sense of the word 'possible,' and what sorts of events would necessarily bring your existence to an end?This is because the question is whether the earlier and later beings are one or two—that is, whether they are numerically identical—and the answer is an account of our persistence conditions. What does it take for a person to persist from one time to another—to continue existing rather than cease to exist? What sorts of adventures is it possible, in the broadest sense of the word ‘possible’, for you to survive, and what sort of event would necessarily bring your existence to an end? What determines which past or future being is you? Suppose you point to a child in an old class photograph and say, “That’s me.” What makes you that one, rather than one of the others? What is it about the way she relates then to you as you are now that makes her you? For that matter, what makes it the case that anyone at all who existed back then is you? This is sometimes called the question of personal identity over time. That’s because it’s about whether the earlier being and the later being are one or two—that is, whether they are numerically identical. An answer to it is an account of our persistence conditions.

This question has historically arisen out of the hope (or fear) that we might continue to exist after we die (as in Plato's Phaedo), but whether this is possible depends on whether biological death necessarily ends one's existence.Consider the possibility that after your death, there will be someone who resembles you in certain ways. How would that being have to relate to you as you are now in order to be you, rather than someone else? What would the Higher Powers have to do to keep you in existence after your death? Or is there anything they could do? The answer to these questions is dependent on the answer to the persistence question.

Evidence. How do we determine who is who? What evidence bears on the question of whether the person here now is the same person who was here yesterday? One source of evidence is first-person memory: if you remember (or appear to remember) doing a particular action, and someone actually did it, this supports the claim that that person is you.Another source is physical continuity: if the person who did it looks exactly like you, or even better, if she is physically or spatio-temporally continuous with you, that is reason to believe she is you. Which of these sources is more fundamental? For example, does first-person memory count as evidence in and of itself, or only insofar as we can check it against publicly available physical facts? What should we do when they support opposing verdicts?Should we conclude, based on memory evidence, that the resulting person is not Charlie but Guy Fawkes brought back to life, or should we instead infer, based on physical continuity, that he is simply Charlie with different memories? How do we find out who is who? What evidence bears on the question of whether the person here now is the one who was here yesterday? One source of evidence is first-person memory: if you remember doing some particular action (or seem to), and someone really did do it, this supports the claim that that person is you. Another source is physical continuity: if the person who did it looks just like you, or even better if she is in some sense physically or spatio-temporally continuous with you, that too is reason to think she is you. Which of these sources is more fundamental? Does first-person memory count as evidence all by itself, for instance, or only insofar as we can check it against publicly available physical facts? What should we do when they support opposing verdicts? Suppose Charlie’s memories are erased and replaced with accurate memories (or apparent memories) of the life of someone long dead—Guy Fawkes, say (Williams 1956–7). Ought we to conclude, on the basis of memory evidence, that the resulting person is not Charlie but Guy Fawkes brought back to life, or should we instead infer on the basis of physical continuity that he is simply Charlie with different memories? What principle would answer this question?

From the 1950s to the 1970s, the evidence question dominated the anglophone literature on personal identity (good examples include Shoemaker 1963, 1970, and Penelhum 1967, 1970), and it is important to distinguish it from the persistence question.What it takes for you to persist over time is one thing; how we should evaluate the relevant evidence is another. For example, if the criminal has fingerprints that match yours, the courts may conclude that he is you.But, even if they are correct, having your fingerprints isn't what it takes for a past or future being to be you: it's neither necessary (you could survive without any fingers at all) nor sufficient (someone else could have fingerprints that look exactly like yours).

If the persistence question is about which of the characters introduced at the beginning of a story have survived to become those at the end, we can also ask how many characters are on the stage at any given time.What determines how many of us there are now? If there are some seven billion people on the planet at the moment, what facts—biological, psychological, or whatever—make that the right number? The question is not what causes there to be a certain number of people at a given time, but what that number consists of. It's like asking what kind of chess configuration amounts to winning, rather than what kinds of moves typically lead to winning. If the persistence question is about which of the characters introduced at the beginning of a story have survived to become those at the end of it, we may also ask how many are on the stage at any one time. What determines how many of us there are now? If there are some seven billion people on the earth at present, what facts—biological, psychological, or what have you—make that the right number? The question is not what causes there to be a certain number of people at a given time, but what there being that number consists in. It’s like asking what sort of configuration of pieces amounts to winning a game of chess, rather than what sorts of moves typically lead to winning.

You might believe that the number of people at any given time (or at least the number of human people) is simply the number of human organisms present at the time (ignoring any that do not count as people), but this is debatable.Some argue that severing the main connections between the cerebral hemispheres causes radical disunity of consciousness and, as a result, two people share a single organism (see, for example, Nagel 1971; Puccetti 1973 argues that there are two people within each normal human being; see also van Inwagen 1990: 188-212).Others argue that a multi-personality human being could literally be the home of two or more thinking beings (Wilkes 1988: 127f., Rovane 1998: 169ff. ; see also Olson 2003b, Snowdon 2014: ch. 7).Others argue that in cases of conjoined twinning, two people can share an organism (Campbell and McMahan 2010; see also Olson 2014).

This is sometimes referred to as the "synchronic identity" problem, as opposed to the "diachronic identity" problem of the persistence question; however, these terms must be used with caution.They may give the incorrect impression that identity is divided into two types, synchronic and diachronic, when the truth is that there are two types of situations in which we can ask how many people (or other things) there are: those involving only one moment and those involving several.

What am I? What sort of things, metaphysically speaking, are you and I and other human beings? What, for example, are we made of? Are we entirely composed of matter, as stones are, or are we partly or entirely immaterial? Where do our spatial boundaries lie, if we are spatially extended at all? Do we extend all the way out to our skin and no further, for example? If so, what fixes those bounda What sort of things, metaphysically speaking, are you and I and other human people? What are our fundamental properties, in addition to those that make us people? What, for instance, are we made of? Are we composed entirely of matter, as stones are, or are we partly or wholly immaterial? Where do our spatial boundaries lie, if we are spatially extended at all? Do we extend all the way out to our skin and no further, for instance? If so, what fixes those boundaries? Are we substances—metaphysically independent beings—or is each of us a state or aspect or activity of something else?

Here are a few of the main proposed solutions (Olson 2007):

  • Snowdon 1990, 2014, van Inwagen 1990, Olson 1997, 2003a define us as biological organisms ("animalism": Snowdon 1990, 2014, van Inwagen 1990, Olson 1997, 2003a).
  • We are material things "constituted by" organisms: a person is made of the same matter as an animal, but they are not the same thing because what it takes for them to survive differs (Baker 2000, Johnston 2007, Shoemaker 2011).
  • We are temporal parts of animals: each of us represents an organism in the same way that your childhood represents your life as a whole (Lewis 1976).
  • We are either spatial parts of animals (Campbell and McMahan 2010, Parfit 2012) or temporal parts of animals (Hudson 2001, 2007).
  • As Plato, Descartes, and Leibniz thought (see also Unger 2006: ch. 7), we are partless immaterial substances—souls—or compound things made up of an immaterial soul and a material body (Swinburne 1984: 21).
  • We are collections of mental states or events, as Hume put it (1739 [1978: 252]; see also Quinton 1962, Campbell 2006).
  • We are nothing: we do not exist at all (Russell 1985: 50, Wittgenstein 1922: 5.631, Unger 1979, Sider 2013).

On this issue, there is no agreement or even a dominant viewpoint.

What is the practical significance of facts about our persistence? Why does it matter? What reason do you have to care whether you continue to exist, rather than someone else just like you existing in your place? Assume that surgeons are going to put your brain into my head and that neither of us has a choice. Assume that the resulting person will be in excruciating pain unless one of us pays a large sum in advance.Which of us would have a reason to pay if we were both completely selfish? Will the resulting person—who will presumably believe he is you—be responsible for your actions or mine? (Or both, or neither?) What is the practical importance of facts about our persistence? Why does it matter? What reason have you to care whether you yourself continue to exist, rather than someone else just like you existing in your place? Imagine that surgeons are going to put your brain into my head and that neither of us has any choice about this. Suppose the resulting person will be in terrible pain after the operation unless one of us pays a large sum in advance. If we were both entirely selfish, which of us would have a reason to pay? Will the resulting person—who will presumably think he is you—be responsible for your actions or for mine? (Or both, or neither?)

The answer may appear to be entirely dependent on whether the resulting person is you or I, but only I am accountable for my actions.The fact that someone is me is reason enough for me to care about him; each person has a special, selfish interest in her own future and no one else's.Identity is important in practice, but some argue that I may have a completely selfish reason to care about someone else's future for his own sake.Perhaps what makes me care about what happens to the man people will call by my name tomorrow is not that he is me, but that he is psychologically continuous with me as I am now (see Section 4), or that he relates to me in some other way that does not imply that we are the same person. If someone other than me were psychologically continuous with me as I am now tomorrow, he would have what matters to me, and I should transfer my selfish concern to him.Similarly, someone else could be held accountable for my actions but not for his own; identity has no practical significance.(See, for example, Shoemaker 1970: 284; Parfit 1971, 1984: 215, 1995; Sosa 1990; Martin 1998.)

That concludes our survey; while some of these questions may have an impact on others, they are largely independent.It's critical not to mix them up.

2. Understanding the Persistence Question

We now turn to the issue of persistence. Few concepts have caused more confusion than identity over time.The Persistence Question is frequently confused with other questions or stated in a biased manner.

The question is roughly what is required and sufficient for a past or future being to be someone existing now. For example, suppose we point to you now, describe someone or something existing at another time, and ask whether we are referring to one thing twice or once to each of two things.The persistence question inquires as to what determines the answer to such queries. (Analogous questions about the persistence of other objects, such as dogs, exist.)

Some interpret the persistence question to mean "what it means to say that a past or future being is you," implying that we can answer it by deciphering terms like "person" or analyzing the concepts they express.If the answer is knowable a priori, it implies that all people must have the same persistence conditions—that the answer is the same regardless of the type of people considered.Though some support these claims (Noonan 2003: 86-92), they are contested. What it takes for us to survive may be determined by whether we are biological organisms, which we cannot know a priori.And, if there are immaterial people, such as gods or angels, what it takes for them to survive may be different from what it takes for a human to survive.

We sometimes wonder what it takes for someone to remain the same person; the idea is that if you changed in certain ways—say, if you lost much of your memory, became severely disabled, or experienced a dramatic change in personality—you would no longer be the person you were before.This is not the persistence question; the answers to the two questions may differ.If you change in such a way that you "become a different person," the answer to the question of whether you are the same person is No; the persistence question asks whether you would still exist in this case.And the answer is yes: you still exist if you are a different person, just as you do if you remain the same person.

When we talk about remaining the same person or becoming a different one, we mean remaining or ceasing to be a certain type of person; for someone to no longer be the same person is to still exist, but to have changed in some significant way.This has nothing to do with persistence and everything to do with her individual identity in the sense of the characterization question—what kinds of changes would count as losing the properties that define someone as a person.Inquiring as to what it takes for someone to "retain or lose her personal identity" appears to be about characterization rather than persistence.

The persistence question is frequently used to ask what it takes for the same person to exist at two different times, with the most common formulation being:

  1. If a person x exists at one point in time and a person y exists at another, under what circumstances could x be y?

This question asks, in effect, what it takes for a past or future person to be you; we have a person existing at one time and another, and the question is what is necessary and sufficient for them to be one person rather than two.

We may want to know whether each of us was ever an embryo or a foetus, or whether someone could survive in an irreversible vegetative state (where the resulting being is biologically alive but lacks mental properties).These are obviously questions about what it takes for us to survive, but being a person is most often defined as possessing unique mental characteristics.For example, Locke stated that a person is "a thinking intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing, in different times and places" (1975: 335), implying that something is a person at a given time only if it possesses those mental properties.As a result, early-term foetuses and people in vegetative states, who have no mental properties at all, are not people at those times, and we cannot infer anything about whether you were once an embryo or could become a vegetable from a principle about what it takes for a past or future person to be you.

Consider the following response to question number one:

A person x existing at one time is necessarily a person y existing at another time if and only if x can remember an experience y has at the second time, or vice versa.

That is, you are a past or future person only if you (as a person now) can remember an experience she had then, or she can remember an experience you are having now (call this the memory criterion).(It is also sometimes attributed to Locke, though it is questionable whether he actually held it: see Behan 1979.)

The memory criterion may appear to imply that if you enter an irreversible vegetative state, you would cease to exist (or perhaps pass to the next world): the resulting being could not be you because it would not remember anything, but this is not the case.Assuming that a human vegetable is not a person, this is not a case of a person existing at one time and another. The memory criterion purports to tell us which past or future person you are, but not which past or future being you are generally.It says what it takes to be a person but not what it takes to be a person without qualification, so it says nothing about whether you could become a vegetable or even a corpse, or whether you were ever an embryo.As previously stated, the memory criterion allows you to survive with no memory continuity at all as long as this occurs when you are not a person (Olson 1997: 22-26, Mackie 1999: 224-228).

The memory criterion is intended to imply that if a person x exists now and a being y exists at another time--whether or not it is a person then--they are one just because x can now remember an experience y had at the other time or vice versa.However, this is not an answer to Question 1: what it takes for a person to exist at one time and a person to exist at another time to be one rather than two; rather, it is an answer to a more general question: what it takes for something that is a person at one time to exist at another time, whether as a person or not:

  1. If a person x exists at one point in time and something y exists at another, under what circumstances could x be y?

Those who state the persistence question as Question 1 do so because they believe that every person is essentially a person: nothing that is in fact a person can exist without being a person. (By contrast, nothing that is in fact a student can exist without being a student.) This claim, known as "person essentialism," implies that whatever is a person at one time must be a person at every time she exists.It equalizes Questions 1 and 2.

But, when combined with a Lockean account of personhood, person essentialism implies that you could never have been an embryo: at best, you could have come into being when the embryo that gave rise to you developed certain mental capacities.You could not become a human vegetable, and it also rules out our being biological organisms, because no organism is essentially a person: every human organism begins as an embryo and may end up in a vegetative state.It excludes both animalism and the brute-physical viewpoint described in the following section.

Whether we were once embryos or could become vegetables, or whether we are essentially people, are substantive questions that should be answered by an account of our persistence, not matters that should be unwittingly settled in advance by the way we frame the debate. Question 1 is tendentious, because it assumes that we can only survive as people.Question 2 is unanswerable.

3. Accounts of Our Persistence

There are four main types of answers to the persistence question, the most popular of which are psychological-continuity views.They claim that our persistence is based on a psychological relationship in which you are the future being who inherits its mental features from you—beliefs, memories, preferences, rational thought capacity, and so on—and you are the past being whose mental features you have inherited in this way.There is disagreement about what kind of inheritance this must be—whether it must be supported by physical continuity, for example, and whether it requires a "non-branching" restriction; there is also disagreement about what mental characteristics must be inherited.(We will return to some of these points.) However, most philosophers writing on personal identity since the early twentieth century have supported some version of this view, with the memory criterion being an example.Garrett (1998), Hudson (2001, 2007), Johnston (1987, 2016), Lewis (1976), Nagel (1986: 40), Noonan (2003), Parfit (1971; 1984: 207; 2012), Perry (1972), Shoemaker (1970; 1984: 90; 1997; 1999, 2008, 2011), and Unger (1990: ch. 5; 2000) are all supporters of psychological continuity.

A second answer is that our persistence is based on some sort of brute physical relation: you are that past or future being who has your body, or is the same biological organism as you are, or something along those lines.It has nothing to do with psychological facts; instead, call these views brute-physical.(Do not confuse them with the belief that physical evidence takes precedence over psychological evidence in determining who is who; this is a matter of evidence.) Their supporters include Ayers (1990: 278-292), Carter (1989), Mackie (1999), Olson (1997), van Inwagen (1990: 142-188), and Williams (191956-7, 1970).

Some attempt to reconcile these viewpoints, claiming that we require both mental and physical continuity to survive, or that either would suffice in isolation (Nozick 1981: ch. 1, Langford 2014).

Narrativism proposes that what it takes for us to persist has to do with the stories we tell about ourselves; we understand our lives in terms of narratives about significant events in our past and their impact on our later decisions and character.These narratives have the potential to be "identity-constituting," in the sense that they bear on our "personal identity" in the sense of the characterization question—what kind of people we are in some fundamental way.They literally determine when we begin and end. Roughly speaking, a past being is you if you now have appropriate narratives identifying you with her as she was then.A future being is you only if the narratives she has then identify her with you as you are now; remembering a past event is necessary but not sufficient for it to figure in an identity-constituting narrative, distinguishing narrativist from psychological-continuity views.Schechtman (1996: esp. ch.) is a narrativeist on persistence.5, 2001) and Schroer and Schroer (2014); detractors include Strawson (2008) and Olson and Witt (2019).3 provides a good overview.

All of these perspectives agree that something is required for us to persist—that there are informative, nontrivial necessary and sufficient conditions for a person existing at one time to exist at another. A fourth perspective, anticriterialism, disagrees.According to Merricks (1998; see also Swinburne 1984, Lowe 1996: 41ff., 2012; Langford 2017; for criticism, see Zimmerman 1998, Shoemaker 2012), psychological and physical continuity are evidence for persistence but do not always guarantee it and may not be required.There are anticriterialist perspectives on things other than people, and there is disagreement about how anticriterialism should be defined (Olson 2012, Noonan 2011, 2019).

4. Psychological-Continuity Views

Most people—at least most Western philosophy teachers and students—are drawn to psychological-continuity views right away (Nichols and Bruno 2010 provide experimental evidence for this). If your brain were transplanted, and that organ carried your memories and other mental features, the resulting person would be convinced that he or she was you.This can make it easy to believe that the person is you, and that this is because she was psychologically consistent with you; however, getting from this thought to an appealing answer to the persistence question is difficult.

We have already mentioned memory: a past or future being might be you if and only if you can now remember an experience she had then, or vice versa. This proposal faces two objections, dating back to Sergeant and Berkeley in the 18th century (see Behan 1979), but more famously discussed by Reid and Butler (see the snippets in Perry 1975).

Assume a young student is fined for late library books and later, as a middle-aged lawyer, she recalls paying the fine.Later, in her dotage, she recalls her legal career but has completely forgotten not only paying the fine but also all the other events of her youth, according to the memory criterion.If x and y are one and y and z are one, then x and z cannot be two. Identity is transitive; memory continuity is not.

Second, it appears to be inherent in the concept of remembering that you can only remember your own experiences; remembering paying a fine (or the experience of it) is to remember yourself paying.That makes saying that you are the person whose experiences you can remember trivial and uninformative—that memory continuity is sufficient for us to persist—trivial and uninformative because you cannot know whether someone genuinely remembers a past experience without first knowing whether she is the one who had it.If we want to know whether Blott, who exists now, is the same as Clott, who we know existed at some point in the past, the memory criterion tells us that Blott is Clott if Blott can now recall an experience Clott had at that point in time.However, Blott's appearing to remember one of Clott's experiences counts as genuine memory only if Blott is Clott. Thus, we should already know whether Blott is Clott before applying the principle that is supposed to tell us whether she is Clott.(However, the claim that memory connections are required for us to persist is not trivial or uninformative; we can know that the corpse resulting from my death cannot remember any events from my life without already knowing whether it is me.)

The first problem (about transitivity) is commonly addressed by changing the memory criterion from direct to indirect memory connections: the old woman is the young student because she can recall experiences the lawyer had at a time when the lawyer remembered the student's life. The second problem is commonly addressed by replacing memory with a new concept, "retrocognition" or "quasi-memory," which is similar to memory but lacks the identity requirement: even if it's

Neither move, however, gets us very far because both the original and modified memory criteria face a more obvious problem: there are many times in our pasts that we cannot remember or quasi-remember at all, and to which we are not even indirectly linked by an overlapping chain of memories.The memory criterion implies that you never existed when you were unconscious, and that the person sleeping in your bed last night must have been someone else.

A better solution replaces memory with the broader concept of causal dependence (Shoemaker 1984, 89ff.).A being is psychologically connected to you at some future time if she is in the psychological states she is in now in large part because of the psychological states you are in now (and this causal link is of the right sort: see Shoemaker 1979).The important point is that our current mental states can be caused in part by unconscious mental states; for example, most of your current beliefs are the same ones you had while sleeping last night: they have caused themselves to continue existing.We can then say that you are psychologically continuous right now, with a past or future being just if some of your current mental states are related to those he or she is in right now via a chain of psychological connections.

Assume that a person x who exists at one time is the same thing as something y who exists at another time if and only if x is psychologically continuous with y at both times, avoiding the most obvious objections to the memory criterion.

However, it leaves important questions unanswered. Suppose we could somehow copy all of your brain's mental contents to mine, much like we can copy the contents of one computer drive to another, and that this erased the previous contents of both brains.Whether this is a case of psychological continuity depends on the type of causal dependence considered; the resulting being (with my brain and your mental contents) would be mentally as you were before, rather than as I was.In a strange way, he would have inherited your mental properties. Is this the correct way? Could you literally move from one organism to another by "brain-state transfer"? Psychological-continuity theorists disagree (Shoemaker (1984: 108-111, 1997) says yes; Unger (1990: 67-71) says no; see also van Inwagen 1997)(Another type of objection to the psychological-continuity strategy is advanced by Schechtman in 2001.)

5. Fission

A more serious concern for proponents of psychological continuity is that you could be psychologically continuous with two people in the past or future at the same time. If your cerebrum—the upper part of the brain largely responsible for mental features—were transplanted, the recipient would be psychologically continuous with you (even if there would be significant psychological differences).Any psychological-continuity viewpoint will imply that she is you, and if we destroyed one of your cerebral hemispheres, the resulting being would be psychologically continuous with you as well.(Hemispherectomy—even the removal of the left hemisphere, which controls speech—is considered a drastic but acceptable treatment for otherwise-inoperable brain tumors: see Rigterink 1980.) What if we did both at the same time, destroying one hemisphere and transplanting the other? Then, too, the person who received the transplanted hemisphere would be psychologically continuous with you, and would be you according to the psychological-continuity view.

Assume that both hemispheres are transplanted, each into a different empty head. (We don't have to pretend that the hemispheres are identical.) The two recipients, dubbed Lefty and Righty, will be psychologically continuous with you.As previously stated, the psychological-continuity view implies that any future being who is psychologically continuous with you must be you, implying that you are both Lefty and Righty.But that cannot be: if you and Lefty are one and you and Righty are one, Lefty and Righty cannot be two, yet they are: there are undeniably two people following the operation.One thing cannot be numerically identical to two distinct things. For example, suppose Lefty is hungry when Righty isn't.If you're a Lefty, you're hungry at that time; if you're a Righty, you're not.If you are both Lefty and Righty, you are both hungry and not hungry at the same time: a blatant contradiction.

Psychological-continuity theorists have proposed two solutions to this problem. The first, known as the "multiple-occupancy view," contends that if fission occurs in the future, there will be two of you even now.What we call you are actually two people who are now identical and in the same place, doing the same things and thinking the same thoughts; the surgeons simply separate them (Lewis 1976, Noonan 2003: 139-42; Perry 1972 offers a more complex variant).

The multiple-occupancy view is frequently combined with the broader metaphysical claim that people and other persistent things are made up of temporal parts (often referred to as "four-dimensionalism"; see Heller 1990: ch. 1, Hudson 2001, Sider 2001a, Olson 2007: ch.5). For each person, there is a first half: an entity similar to the person but shorter in duration, similar to the first half of a meeting.According to this account, Lefty and Righty coincide before the operation by sharing their pre-operative temporal parts or "stages," and diverge later by having different temporal parts located afterwards; they are analogous to two roads that coincide for a stretch and then fork, sharing some but not all of their spatial parts.Where the roads intersect, they are just like one road; similarly, before the operation, when Lefty and Righty share their temporal parts, they are just like one person.Even they can't tell they're two, but whether we're really made up of temporal parts is debatable.(Its implications are discussed further in Section 8.)

The alternative solution to the fission problem rejects the intuitive claim that psychological continuity alone is sufficient for us to persist, instead stating that a past or future being is you only if she is psychologically continuous with you and no other being is.(There is no circularity here; we don't need to know the answer to the persistence question to know how many people are present at any given time; that comes under the population question.) This means that neither Lefty nor Righty is you.They both exist when your cerebrum is divided; if both of your cerebral hemispheres are transplanted, you die (though you would survive if only one were transplanted and the other destroyed).(Shoemaker 1984: 85; Parfit 1984: 207; 2012: 6f., Unger 1990: 265, Garrett 1998: ch.)4).

The "non-branching view" proposes that if your brain is divided, you will survive if only one half is preserved, but you will die if both halves are preserved, which appears to be the opposite of what we should expect: if your survival depends on the functioning of your brain (because that is what underpins psychological continuity), then the more of that organ we preserve, the better your chances of survival should be.In fact, the non-branching view implies that you would die if one of your hemispheres were transplanted while the other remained in place: you can only survive hemispherectomy if the hemisphere to be removed is first destroyed.If your brain is to be divided, why do we need to destroy half of it in order to save you? (See Noonan 2003: 12-15 and ch. 7.)

If brain-state transfer is considered psychological continuity, even copying your entire brain state to another brain without causing you any physical or psychological harm would kill you.("Best-candidate" theories like Nozick 1981: chapter 1 try to avoid this.)

When faced with the prospect of having one of your hemispheres transplanted, there is no obvious reason to prefer having the other destroyed, according to the non-branching viewpoint.Most of us would prefer to preserve both, even if they go into different heads; however, on the non-branching view, that is to prefer death over continued existence,This leads Parfit and others to argue that this is exactly what we should prefer: we have no reason to continue existing, at least for our own sake.What you really want is for someone to be psychologically consistent with you in the future, whether or not she is you.

The usual way to accomplish this is to continue existing yourself, but the fission story demonstrates that this is not required; similarly, even the most selfish person has a reason to care about the well-being of the beings who would result from her fission, even if, as the non-branching view implies, neither would be her.The kinds of practical concerns you normally have for yourself apply to someone else in the fission case, implying that facts about who is who have no practical significance.(Lewis 1976 and Parfit 1976 debate whether the multiple-occupancy view can maintain the conviction that identity is what matters practically.)

6. The Too-Many-Thinkers Problem

Another criticism leveled at psychological-continuity theories is that they rule out our existence as biological organisms (Carter 1989, Ayers 1990: 278-292, Snowdon 1990, Olson 1997: 80f., 100-109, 2003a). This is because no type of psychological continuity appears to be either necessary or sufficient for a human organism to persist.Human organisms have brute-physical persistence conditions; if your brain were transplanted, the person who received it would be psychologically and physically continuous with you (and this continuity would be continuously realized).She would be you in any psychological-continuity view: the person would go with her transplanted brain, but no organism would go with its transplanted brain.The operation appears to simply transfer an organ from one organism to another.It follows that if you were an organism, you would remain behind with an empty head, which, while unlikely, demonstrates that we have a property that no organism has, namely the ability to move from one organism to another via brain transplant.

Again, a human organism could continue to exist in an irreversible vegetative state with no psychological continuity, as could you if you were an organism.But, according to psychological-continuity theories, you couldn't, so human animals have a property that we don't, namely the ability to survive as a vegetable.

This not only rules out our being organisms essentially or "fundamentally," but also our being organisms at all: nothing that is even contingently an organism would go with its transplanted brain, or would cease to exist simply by entering an irreversible vegetative state.

However, a healthy, adult human organism appears to be a paradigm case of a thinking being. If human organisms can think, but we are not organisms (as psychological-continuity views imply), three difficulties arise.First, you are one of two intelligent beings reading this entry, and there are two thinking beings where we thought there was only one.

Second, the organism would presumably be psychologically indistinguishable from you, making it a person if being a person entails having certain mental or behavioral properties (according to Locke's definition)—a second person in addition to you.In that case, it cannot be true that all people (or even all human beings) persist through psychological continuity, because some—those that are organisms—would have brute-physical persistence conditions.

Third, it's difficult to see how you could tell if you were a nonanimal person with psychological persistence conditions or an animal person with brute-physical ones; if you thought you were the nonanimal, the organism would use the same logic to conclude that you were too.It appears that you, for all you know, are the one making this mistake.

Imagine a three-dimensional duplicating machine that reads off your complete physical (and mental) condition and uses this information to assemble a perfect duplicate of you in the "out" box when you step into the "in" box.The process induces temporary unconsciousness but is otherwise safe; two beings awaken, one in each box.Because each being will have the same apparent memories and perceive identical surroundings, each will believe, for the same reasons, that he or she is you.But only one will be correct, and if this happened to you, it's difficult to know whether you were the original or the duplicate.(Assume the technicians who operate the machine are sworn to secrecy and immune to bribes.) You would wonder, "Who am I? Did I do the things I seem to remember doing? Or did I come into being only a moment ago, complete with false memories of someone else's life?" And you would have no way of answering these questions. In the same way, psychological-continuity views raise the questions, "What am I? Am I a nonanimal that

The "too-many-thinkers" or "thinking-animal" problem refers to these three objections.

The most popular psychological-continuity defense against this objection is that, despite sharing our brains and displaying all the outward signs of consciousness and intelligence, human organisms do not think and are not conscious; thinking animals are not a problem for psychological-continuity views because there are none (Shoemaker 1984: 92-97, Lowe 1996: 1, Johnston 2007: 55; Baker 2000 is a subtle variant).If human organisms cannot be conscious, it would seem that no biological organism of any kind could have any mental properties at all, according to Shoemaker's functionalist theory of mind (1999, 2008, 2011).This raises the possibility that human organisms are "zombies" in the philosophical sense: beings that are physically identical to conscious beings, have the same behavior, but lack consciousness (Olson 2018).

Another option is to admit that human organisms are psychologically indistinguishable from us while attempting to explain how we can still know that we are not those organisms. The most well-known proposal of this type focuses on personhood and first-person reference.It states that a person is not just any being with mental properties like yours and mine—rationality and self-consciousness, for example—but that a person must also persist through psychological continuity.As a result, human animals are not people (which solves the second problem of personhood).

Furthermore, personal pronouns such as 'I' and the thoughts they express only refer to people, so when your animal body says or thinks 'I,' it is referring to you, the person.The organism's statement 'I am a person' expresses the true belief that you are, not the false belief that it is a person, so the organism is not confused about what it is: it has no first-person beliefs about itself at all.You are also not mistaken; you can deduce that you are a person based on the linguistic facts that you are whatever you refer to when you say 'I,' and that 'I' never refers to anything other than a person.You can tell that you are not the animal thinking your thoughts because it is not a person and personal pronouns never refer to nonpeople (thus solving the third, epistemic problem).

Alternatively, human organisms have psychological persistence conditions. Contrary to appearances, the transplant operation would cut an organism down to the size of a brain, move it across the room, and then give it new parts to replace the ones it lost—presumably destroying the animal into which the brain is implanted.(This is consistent with Wiggins (1980: 160, 180) and McDowell (1997: 237), as well as Madden (2016); see also Langford 2014, Olson 2015: 102-106.)

7. Brute-Physical Views

None of these objections arise from animalism, the belief that we are organisms; however, this does not imply that all organisms, or even all human organisms, are people: as we previously discussed, human embryos and animals in a persistent vegetative state may not be considered people.Being a person, like being a student, may be a temporary property of yours, and animalism does not imply that all people are organisms.It is consistent with the existence of entirely inorganic people, such as gods, angels, or conscious robots, and it does not state that being an animal is part of what it is to be a person (a viewpoint supported by Wiggins 1980: 171 and Wollheim 1984: ch).1 and criticized in Snowdon 1996). Animalism leaves the question of personhood unanswered.(It is, for example, consistent with Locke's definition quoted in section 2.)

Animalism implies a version of the brute-physical view, assuming that organisms persist due to some sort of brute-physical continuity; some endorse a brute-physical view without saying that we are animals.They claim that we are our bodies (Thomson 1997), or that our identity over time consists in the identity of our bodies (Ayer 1936: 194), and this is known as the bodily criterion of personal identity.It is enigmatic, and its relationship to animalism is unclear.

Most versions of the brute-physical view imply that human beings have the same persistence conditions as certain nonhumans, such as dogs, and that our persistence conditions differ from those of immaterial people, if such distinctions are possible.As a result, there are no persistence conditions for people as such (Baker (2000: 124) strongly disagrees.)

The most common objection to brute-physical views is the implication that if your brain were transplanted, you would remain behind (e.g., Unger 2000; for an important related objection, see Johnston 2007, 2016).In other words, brute-physical viewpoints are unappealing in the same way that psychological-continuity viewpoints are appealing.

Animalists generally acknowledge the force of this, but believe it is outweighed by other considerations. For starters, animalism avoids the problem of too many thinkers.Second, it is consistent with our beliefs about who is who in real life: every actual case in which we believe someone will live or die is a case in which a human organism will live or die.Psychological-continuity beliefs, on the other hand, contradict the appearance that each of us was once a foetus. When we see an ultrasound picture of a 12-week-old foetus, we normally think we are seeing something that will be born, learn to speak, and eventually become an adult human being if all goes well.However, none of us are psychologically compatible with a 12-week-old fetus.

And the "transplant argument" may be less compelling than it appears (Snowdon 2014: 234). Assume you have a tumor in your brain that will kill you unless it is replaced with a healthy donated organ.This would have serious consequences: it would destroy your memories, plans, preferences, and other mental properties, and it is unclear whether you would be able to survive such an event.But it's not impossible that you could survive it; perhaps the operation could save your life, albeit at a high cost.Even if the new brain gave you memories, plans, and preferences from the donor, we can't rule it out with certainty. But if it's not obvious that the brain recipient isn't you, it's not obvious that it's the donor.The claim is not that a brain transplant is obviously true, but rather that it is not obviously false.And it is not obvious that a person must go with her transplanted brain in that case.

8. Wider Themes

The debate between psychological-continuity and brute-physical viewpoints cannot be resolved without considering more general issues outside of personal identity, such as why human organisms are unable to think as we do.This will necessitate an explanation of the nature of mental properties, or, if human organisms can think, how we can know that we are not those organisms.This will depend on how personal pronouns and proper names are referenced, as well as the nature of knowledge.

Some general metaphysical viewpoints contend that there is no single correct answer to the persistence question; the best-known example is the ontology of temporal parts discussed in section 5.It states that for every period of time when you exist, whether short or long, there is a temporal part of you that exists only at that time, which gives us many likely candidates for being you—that is, many different beings now sitting there reading this.Assume you are a material thing, and we know what determines your spatial boundaries; this should tell us what counts as your current temporal part or "stage"—the temporal part of you that exists now and nowhere else.However, that stage is one of many temporally extended objects (Hudson 2001: ch. 4).

It is, for example, a part of a being whose temporal boundaries are determined by psychological continuity relations (Section 4) among its stages; that is, one of the beings thinking your current thoughts is an aggregate of person-stages, each of which is psychologically continuous with each of the others but not with any other stage.If this is who you are, you will survive through psychological continuity; your current stage is also a part of a being whose temporal boundaries are determined by psychological connectedness relations.That is, one of the beings now thinking your thoughts is a collection of person-stages, each of which is psychologically connected to the others but not to any other stage; this may not be the same as the first being, as some stages may be psychologically continuous with your current stage but not psychologically connected with it.If this is who you are, then psychological connectedness is both necessary and sufficient for your survival (Lewis 1976). Furthermore, your current stage is a part of a human organism that survives through brute-physical continuity, as well as a part of many bizarre and gerrymandered objects, such as "contacti persons" (Hirsch 1982, ch.Some even claim that you are your current stage (Sider 2001a, 188-208).There would be numerous other candidates.

The temporal-parts ontology implies that each of us shares our current thoughts with countless beings that diverge from one another in the past or future; if this were true, which of these things should we be? Of course, we are the referents of our personal pronouns and proper names.However, these words are unlikely to be successful in referring to only one type of thing—to only one of the many candidates on each occasion of utterance; there would almost certainly be some indeterminacy of reference, so that each such utterance referred ambiguously to many different candidates.That would make it unclear what we are, and even what kind of things we are, and because the candidates have different histories and persistence conditions, it would be unclear when we came into being and what it takes for us to persist (Sider 2001b).

What happens when a dog walks through fertilized grass?

Fertilizers and Cats and Dogs If your pet consumes commercial lawn fertilizer, it may cause serious health problems such as abdominal pain, excessive drooling, vomiting, discolored gums, bowel obstruction, difficulty breathing, cardiac arrest, and even liver and pancreas inflammation.abdominal pain, excessive drooling, vomiting, discolored gums, bowel obstruction, difficulty breathing, cardiac arrest, and even inflammation of the liver and pancreas.

How long after lawn treatment are pets safe?

How to Protect Your Pet from Lawn Pesticides. If you believe you have no choice but to use pesticides on your lawn, the only thing you can do to protect your pet is to keep it off the lawn for at least 48 hours after the lawn treatment.at least 48 hours after the lawn treatment.

How long until dogs can eat fertilizer?

Waiting two days ensures that pets are not exposed to potentially toxic substances. When our professionals visit your home for a spring fertilizer application, we can provide you with specific information about the fertilizer we are using and its ingredients.two whole days is a surefire way to minimize potentially toxic exposure to pets. When our professionals visit your home for a spring application of fertilizer, we can give you specific information about the fertilizer we are using and its ingredients.

Can dogs become ill after walking on a fertilized lawn?

While commercial fertilizers may provide nutrition for plants, they also contain toxic chemicals that your dog can consume by running and playing outside and then grooming himself.they contain harmful chemicals which are toxic to dogs. Your dog can accidentally consume these chemicals when they are sprinkled on the lawn or garden just by running and playing outside and then grooming himself.