1. Time, Self and Mind (ATS1835) Introduction to Philosophy B Semester 2, 2015
Dr Ron Gallagher
Week 10: Knowledge and Scepticism (1 tutorial left)
swGtM1IuY
What is knowledge? What is justifed true belief?
What is scepticism?
What is doubt?
What is justification?
Can any knowledge be justified?
Can ordinarily accepted statements be justified?
Radical doubt is nonsensical, selective doubt needs grounds for doubt.

2. Time - Introduction and Time Travel
Week
Beginning
Topic
Assessment
Readings W1
27-Jul-14
Time - Introduction and Time Travel
Readings 1.1 & 1.2 W2
03-Aug-14
Time Travel; Freedom, Determinism, and Indeterminism
Readings 1.5 & 1.6 (sections 1-2 & 6-10) W3
10-Aug-14
Logic Primer
AT1 Mon August 10, 10am
Readings W4
17-Aug-14
Mind- Dualism versus Materialism about the Mind
Readings W5
24-Aug-14
Mind - Can Machines Think? Computationalism and the Turing Test
Readings 3.3 W6
31-Aug-14
Mind - Can Machines Think? Objections to Computationalism
AT2 Mon Aug 31st, 10am
Reading 3.4 W7
07-Sep-14
Self - Lockean Psychological Theory and Identity
Readings W8
14-Sep-14
Self - Identity, the Body & Person Stages
Readings W9
21-Sep-14
Knowledge What is Knowledge and Gettier's Account
AT3 Mon Sep 21st, 10am
Readings
28-Sep-14
Mid-semester Break
W10
05-Oct-14
Knowledge - Nozick's Account and Scepticism
Readings
W11
12-Oct-14
Knowledge - The Moorean Response
AT4 Essay Mon Oct 12th
Readings 5.5
W12
19-Oct-14
Revision (no lectures, no tutorials)

3. Assessment Hurdle Requirements to Pass this Unit
Due Date
Assessment Task
Value
Mondays 10am
Reading Quizzes (10)
5% (bonus)
Mon Aug 10th
AT1 words)
10%
Mon Aug 31st
AT2 words)
Mon Sep 21st
AT3 words)
Mon Oct 12th
AT4 Essay words)
30%
TBA
Exam
40%
Hurdle Requirements to Pass this Unit
Your overall grade for the unit must be at least 50%
You must achieve a grade of 40% or more on the final exam
You must not fail more than one assessment task (not including Reading Quizzes)
You cannot miss more than 3 tutorials

4. AT2: Essay Assignment (Due: October 12, 10am)
General Instructions
Word Limit: 1250 words Value: 30%
Presentation Requirements: Your assignment should be presented in 12-point font and 1.5 or double-spaced. It will require references and a bibliography.
Acceptable Formats: .doc or .rtf. (If you want to use some other format, clear it with your tutor beforehand.) Only submit an electronic copy; no hard copy submission required.
File Name: Name your file using the following convention:
[Question Number] [Surname]
Example: "3Silva.doc," "5Smith.rtf", "1Jones.docx"
Referencing and Citation: 
In your essay, you should try to fulfill the following requirements, especially the first:
The essay must address the question asked.
It should have a structure that is clear and organised to form a coherent argument.
You should explain, in your own words, views and arguments in the prescribed readings that are relevant to the topic. Be careful to present these views fairly and accurately, with adequate citation detail.
You should try to evaluate the arguments you have discussed, and in the process work out your own position. When you criticise a philosopher, try to think how she might reply to your objections.
You must carefully identify all connections between your essay and the writings of others.

11. ESSAY MARKING CRITERIA - from ATS1835 Unit Guide

12. ESSAY FAQs The word limit is +/- 10% of 1250 words.
You are required to use at least one of the readings (not just the commentary or lecture slides) from the TSM Reader as your primary text.
You can reference the TSM Reader by page number, eg (Kane, 2007,TSM Reader p.56), you do not need to use the original page numbers of the individual papers in the Reader.
Begin the essay with a statement of YOUR thesis (eg You believe that machines do not think, and that Turing is wrong for such and such a reason and that Searle makes some good points) and how you are going to support it with arguments from the TSM Reader

13. From Sample Exam - now on Moodle
11. What is the traditional analysis of knowledge? Explain it and then provide a Gettier-style counterexample to it—either one of Gettier’s own counterexamples, one discussed in the literature, or one you have made up yourself (doing the latter of course is most impressive). Explain exactly how the counterexample is meant to work.
12. How does Nozick try to use his tracking theory to object to the “closure argument” used by skeptics who maintain we cannot know if there is an external world? (Note: If you use abbreviations or formal symbols, be sure to say what they represent.)
13. What is Cartesian skepticism? And how does Descartes’ line of reasoning support it?

14. AT4 Essay - Mon Oct 12th, 10am - @1250 words – 30%
Essay Topics
Write on one of the following topics.
AT4 Essay - Mon Oct 12th, 10am words – 30%
5. Knowledge
Gettier raises some serious challenges for the traditional account of knowledge. Nozick develops his tracking account in part to answer the problems identified by Gettier. After explaining both Gettier's challenge and Nozick's proposal, evaluate the strength of Nozick's proposal as a response to Gettier's challenge.
Required reading:
Edmund Gettier, 'Is Justified True Belief Knowledge?'
Robert Nozick, 'Knowledge and Skepticism'

15. 1. Knowledge as Justified True Belief
There are three components to the traditional (“tripartite”) analysis of knowledge. According to this analysis, justified, true belief is necessary and sufficient for knowledge.
The Tripartite Analysis of Knowledge:
S knows that p iff
p is true;
S believes that p;
S is justified in believing that p.
The tripartite analysis of knowledge is often abbreviated as the “JTB” analysis, for “justified true belief”.
From

16. The Basing Demand The Basing Demand:
General Issue:
S can have terrific evidence to think P true.
S can believe P is true.
But S can fail to believe P because of the evidence.
= S can fail to base her belief in P on the evidence.
= S can believe P for obviously irrelevant reasons.
The Basing Demand:
In order to know P one must have a justified belief in P.
In order to have a justified belief one must base that belief on good reasons.

17. Epistemic Luck (Russell)

18. 3. The Gettier Problem
In his short 1963 paper, “Is Justified True Belief Knowledge?”, Edmund Gettier presented two effective counterexamples to the JTB analysis (Gettier 1963). One of these goes as follows. Suppose Smith has good evidence for the false proposition
(1)Jones owns a Ford.
Suppose further Smith infers from (1) the following three disjunctions:
(2)Either Jones owns a Ford or Brown is in Boston.
(3)Either Jones owns a Ford or Brown is in Barcelona.
(4)Either Jones owns a Ford or Brown is in Brest-Litovsk.
Since (1) entails each of the propositions (2) through (4), and since Smith recognizes these entailments, his beliefs in propositions (2)–(4) are justified. Now suppose that, by sheer coincidence, Brown is indeed in Barcelona. Given these assumptions, we may say that Smith, when he believes (3), holds a justified true belief. However, is Smith's belief an instance of knowledge? Intuitively, Smith's belief cannot be knowledge; it is merely lucky that it is true.

19. Gettier and Propositional Knowledge
Gettier argues that one could have a true justified belief which is not knowledge in a situation in which one reasons from some already justified beliefs to a new belief that, as it happens, is coincidentally true. Since it would then be a matter of coincidence that one’s belief was correct, it would not count as knowledge, even though it was a justified belief because it was knowingly inferred from already justified beliefs.

20. From http://plato.stanford.edu/entries/knowledge-analysis/index.html
Most epistemologists have accepted Gettier's argument, taking it to show that the three conditions of the JTB account—truth, belief, and justification—are not in general sufficient for knowledge. How must the analysis of knowledge be modified to make it immune to cases like the one we just considered? This is what is commonly referred to as the “Gettier problem”.
Above, we noted that one role of the justification is to rule out lucky guesses as cases of knowledge. A lesson of the Gettier problem is that it appears that even true beliefs that are justified can nevertheless be epistemically lucky in a way inconsistent with knowledge.
Epistemologists who think that the JTB approach is basically on the right track must choose between two different strategies for solving the Gettier problem
From

21. Structure of the Counterexample
Reminder: Traditional account says JTB is necessary & sufficient for knowledge.
Question: What does this counterexample teach us about the JTB account of knowledge? JTB is…
(a) Not necessary for knowledge.
(b) Not sufficient for knowledge.
(c) Neither necessary nor sufficient for knowledge.
Structure of the Counterexample:
S has JTB
But: S doesn’t know that p
So: JTB is insufficient for knowledge
How to Proceed: S knows that p iff JTB + ?
Any guesses as to what should be added?

22. Nozick (sensitivity conditions) S knows that p iff: p is true.
S believes p.
If p were false, S would not believe p.
If p were true, S would believe p.
Which is to say:-
s knows that p when the following conditions hold
p is true
s believes p
If p were the case then s would believe p
If p were not the case then s would not believe it

23. Another Gettier-style Case
Second Counterexample: The Sheep Case
You see a white fluffy animal in the field that looks very, very sheep-like. You form the belief there’s a sheep in the field. And, indeed, there is a sheep in the field. But you can’t see it.
So you have a JTB that a sheep is in the field.
But, what you see is not a sheep, but a fluffy white dog that looks very sheep-like. The unseen sheep in the field is hidden from view.
This is not only JTB, but JTB that is not based on any false belief.
From: Chisholm (1966), Theory of Knowledge

24. The Sheep Case (NTA): S knows that p only iff: p is true.
S believes p.
If p were not true, then S would not believe p. …
Question: Is condition 3 satisfied in the Sheep Case? That is, is the following true:
(A) If there were no sheep in the field, S would not believe that there are sheep in the field.
NO! I.e., S would still believe it.
So condition 3 is not satisfied.
So according to Nozick’s theory, one does not know that there is a sheep in the field. This is exactly the conclusion we want.

25. From Sample Exam
What do the Gettier examples show?
(A) That knowledge is justified true belief.
(B) That having a justified, true belief is
sufficient for knowledge.
(C) That having a justified, true belief is
necessary for knowledge.
(D) None of the above.

26. 4. The Self
If you teletransport to another planet, we might wonder whether the resulting individual is you---whether you've really survived. Parfit argues that identity is not what matters when we consider our futures in such cases. How does he reach this conclusion by considering the problem of fission? Is this a good argument? Is there more reason to think that identity does matter to survival? (Here you might focus more on Williams or Lewis, rather than discussing them both in detail.)
Parfit: Not persistence of identity but concern for survival.
Williams: Not psychological continuity, but physical (bodily) continuity)
Lewis: Connected time-stages of personal timelines ensure perdurance.

27. Teleportation
Imagine a teleport machine that works as follows. It scans and records everything about your body, down to the atomic level. That information is then sent to the receiving teleport machine, which reconstructs your body exactly from a stock pile of raw material. The scanning process destroys all the original atoms of your body. Question: Is this really a way to travel? Would you use it?

28. Teleportation

29. Teleportation
Imagine the machine breaks down. An exact duplicate of you is created at the destination, but the original you is not destroyed. Or what if two copies of you were created at the other end? Again, the person / people at the other end are psychologically continuous with you, But are they really you? Most people answer no – this kind of machine is not a way to travel. It just creates a duplicate of you (like an identical twin). Perhaps it is bodily continuity that really matter then, rather than psychological continuity. (Williams)

30. This isn’t what I asked for!
The A-body person has all B’s memories.
Swapping bodies
This isn’t what I asked for! A
A-body person
Yay! B
B-body person
The B-body person has all A’s memories.

31. Parfit’s argument
(1) Identity is a one-one relation that does not admit of degrees. (2) Psychological continuity need not be one-one and can come in degrees. (Fission and fusion cases) (3) What matters in survival is psychological continuity (whether your mental life continues on) Therefore: (C) What matters in survival is not identity. Lewis wants to accept all three premises, but reject the conclusion.

32. Lewis’s theory
Suppose I am wondering whether I will survive a future event. What matters to me? Answer 1: Psychological continuity: whether my mental life ‘flows on’. My current mental states should have successors that are appropriately linked to my current state. Answer 2: Identity: I want there to be someone who is me after the event. Parfit argues that there are cases (eg fission) where these two answers will disagree. Lewis argues against this. Both answers are right and they can never disagree!

33. Temporal stages
Lewis makes use of the idea that a person is a unified whole consisting of temporal stages or temporal parts. Think of a person as a four-dimensional object which is stretched out in time. At any particular time, only the temporal parts are present, never the whole person. This conception of identity through time should be distinguished from an endurantist conception, according to which the whole person is present at all the times that it exists.

34. Tensed Identity
“You may feel certain that you count persons by identity and not tensed identity. But how can you be sure? Normal cases provide no evidence…. The problem cases provide no very solid evidence either. They are problem cases just because we cannot consistently say quite all the things we feel inclined to, We must strike the best compromise among our conflicting opinions. Something must give way: and why not the opinion that of course we count by identity, if that is what can be sacrificed with the least total damage?” Lewis, ‘Survival and Identity’, p. 227

36. 3. Thinking Machines
On the question whether machines can think, Descartes and Turing are in strong disagreement. Evaluate the arguments on either side. Does Searle's 'Chinese Room' argument help resolve the debate?
Required reading:
Alan Turing, 'Computing Machinery and Intelligence'
John Searle, 'Minds, Brains and Programs'
(Quotes from Descartes can be found in the Notes to Part 3 of the Study Guide.)
How does Descartes’ argue against thinking machines?
How does Turing’s argue for thinking machines?
How does Searle argue against thinking machines?
TIP
Don’t confuse thinking, intelligence and consciousness (or syntax, semantics, understanding and intentionality).

37. 2. Free Will
Consider this argument: 'If the future is already determined, then it must be possible to know in advance what will happen. But, if that is so, then free will is impossible.' Do you agree? Is there any satisfactory way of acting freely if determinism is true?
Required reading:
David Lewis, 'The Paradoxes of time Travel'
Richard Taylor, 'Freedom, Determinism and Fate'
Kane, ‘Libertarianism’

38. Consider this argument:
2. Free Will
Consider this argument:
'If the future is already determined, then it must be possible to know in advance what will happen. But, if that is so, then free will is impossible.’
Do you agree?
Is there any satisfactory way of acting freely if determinism is true?
Required reading:
David Lewis, 'The Paradoxes of time Travel'
Richard Taylor, 'Freedom, Determinism and Fate'
Kane, ‘Libertarianism’
Lewis – The future is as fixed as the past, but argues against the ‘tricks of fatalists’ See Lewis p.31 TSM Reader (one assumes he is a compatibilist)
See “Arguments for Incompatibilism” Stanford.
Taylor – Determinism entails fatalism. (He denies free will, his argument here is therefore incompatibilist) Taylor’s Osmo story is a fatalist parable.
Kane – The complexity of ‘free agents’ ensures that choices are real and free.
Kane is a Libertarian – he denies determinism and is therefore an incompatibilist.

39. 1. Fatalism from Stanford
A good deal of work in the philosophy of time has been produced by people worried about Fatalism, which can be understood as the thesis that whatever will happen in the future is already unavoidable (where to say that an event is unavoidable is to say that no human is able to prevent it from occurring). Here is a typical argument for Fatalism.
(1) There exist now propositions about everything that might happen in the future.
(2) Every proposition is either true or else false.
(3) If (1) and (2), then there exists now a set of true propositions that, taken together, correctly predict everything that will happen in the future.
(4) If there exists now a set of true propositions that, taken together, correctly predict everything that will happen in the future, then whatever will happen in the future is already unavoidable.
(5) Whatever will happen in the future is already unavoidable.

40. 1. Time Travel
How can David Lewis's solution to the Grandfather paradox be used to solve the problem of the logically pernicious self-inhibitor discussed in your Unit Reader? Be sure to clearly lay out the problem and the solution to the grandfather paradox, draw the parallels between that paradox and the logically pernicious self-inhibitor problem. Discuss whether the solution to this problem seems as plausible as the solution to the Grandfather paradox.
Required reading:
David Lewis, 'The Paradoxes of Time Travel’
The Logically Pernicious Self‐inhibiter
If time travel is possible, it must be possible to build ‘a logically pernicious self inhibiter’. Here is an example devised by John Earman: Imagine a rocket ship that can fire a probe into its own recent past. Suppose the rocket is programmed to fire the probe unless a safety switch is set to on, and that the safety switch is turned on if and only if the rocket detects the return of the probe. The rocket will fire the probe if and only if it does
not fire the probe. That is impossible. (TSM Reader Page 10)
That is: it can fire the probe and it can’t fire the probe.

41. Earman asks us to consider a rocket ship that at some space-time point x can fire a probe that will travel along a timelike loop into the past lobe of x's light cone. Suppose the rocket is programmed to fire the probe unless a safety switch is on and the safety switch is turned on if and only if the "return" of the probe is detected by a sensing device with which the rocket is equipped ( ). Is the probe fired or not? The answer is that it is fired if and only if it is not fired, which is logically absurd.This contradiction does not suffice to show that time travel per se is impossible. Rather the whole situation is impossible, and this includes assumptions about the programming of the rocket, the safety switch, the sensing device, and so forth. But, although the contradiction could be avoided by giving up some of these assumptions, Earman suggests that we have good evidence that rockets can be so programmed. Earman concludes, "Thus, although we cannot exclude closed timelike lines on logical grounds, we do have empirical reasons for believing that they do not exist in our world" (232).
Earman, John (1972) Implications of causal propagation outside the null cone. Australasian Journal of Philosophy, 50 (3). pp ISSN

42. Logical Paradoxes
This sentence is false.
Everything I say is always a lie.
The Barber Paradox and the Set of All Sets.
“The male barber shaves every man in town who does not shave himself. Who shaves the barber?”
Assuming that every man in town has to get shaven, there is no escape from this dilemma. Bertrand Russell used this exercise to show that certain kinds of classification were impossible.

43. From Sample Exam - now on Moodle
11. What is the traditional analysis of knowledge? Explain it and then provide a Gettier-style counterexample to it—either one of Gettier’s own counterexamples, one discussed in the literature, or one you have made up yourself (doing the latter of course is most impressive). Explain exactly how the counterexample is meant to work.
12. How does Nozick try to use his tracking theory to object to the “closure argument” used by skeptics who maintain we cannot know if there is an external world? (Note: If you use abbreviations or formal symbols, be sure to say what they represent.)
13. What is Cartesian skepticism? And how does Descartes’ line of reasoning support it?

44. 13. What is Cartesian skepticism
13. What is Cartesian skepticism? And how does Descartes’ line of reasoning support it?

46. See p.233 of TSM Reader for summary of Descartes argument.
P1. If I know that P, then I know that I am not a brain in a vat
P2. I do not know that I am not a brain in a vat
Thus, I do not know that P.
The Brain in a Vat Argument is usually taken to be a modern version of René Descartes' argument (in the Meditations on First Philosophy) that centers on the possibility of an evil demon who systematically deceives us.
P1. If I know that P, then I know that I am not being systematically deceived by an evil demon
P2. I do not know that I am not systematically deceived by an evil demon

47. “Knowledge is closed under know logical entailment”
12. How does Nozick try to use his tracking theory to object to the “closure argument” used by skeptics who maintain we cannot know if there is an external world? (Note: If you use abbreviations or formal symbols, be sure to say what they represent.)
Note:-
The argument referred to is the “epistemic closure argument”. See p TSM Reader.
“Knowledge is closed under know logical entailment”
E.g. You know you have hands only if you know you’re not a brain in a vat.
Nozick argues that a belief counts as knowledge only if it tracks the truth.
It’s probably best to outline closure argument first.

51. Nozick’s Tracking Theory (sensitivity conditions)
S knows that p iff:
p is true.
S believes p.
If p were false, S would not believe p.
If p were true, S would believe p.
Which is to say:-
s knows that p when the following conditions hold
p is true
s believes p
If p were the case then s would believe p
If p were not the case then s would not believe it

52. The BIV hypothesis fails to satisfy condition
4. If p were true, S would believe p.
Because:-
If the envatted brain were not electrically stimulated to believe that it was in a vat by its envatters, it would not believe it was in a vat even if it remained true that it was in a vat.
Hence, the following counterfactual is not true of the envatted brain: “If p were true, S would believe that p”.

53. 11. What is the traditional analysis of knowledge
11. What is the traditional analysis of knowledge? Explain it and then provide a Gettier-style counterexample to it—either one of Gettier’s own counterexamples, one discussed in the literature, or one you have made up yourself (doing the latter of course is most impressive). Explain exactly how the counterexample is meant to work.

54. 1. Knowledge as Justified True Belief
There are three components to the traditional (“tripartite”) analysis of knowledge. According to this analysis, justified, true belief is necessary and sufficient for knowledge.
The Tripartite Analysis of Knowledge:
S knows that p iff
p is true;
S believes that p;
S is justified in believing that p.
The tripartite analysis of knowledge is often abbreviated as the “JTB” analysis, for “justified true belief”.
From

55. Epistemic Luck (Russell)

56. Gettier and Propositional Knowledge
Gettier argues that one could have a true justified belief which is not knowledge in a situation in which one reasons from some already justified beliefs to a new belief that, as it happens, is coincidentally true. Since it would then be a matter of coincidence that one’s belief was correct, it would not count as knowledge, even though it was a justified belief because it was knowingly inferred from already justified beliefs.

57. 3. The Gettier Problem
In his short 1963 paper, “Is Justified True Belief Knowledge?”, Edmund Gettier presented two effective counterexamples to the JTB analysis (Gettier 1963). One of these goes as follows. Suppose Smith has good evidence for the false proposition
Jones owns a Ford.
Suppose further Smith infers from (1) the following three disjunctions:
Either Jones owns a Ford or Brown is in Boston.
Either Jones owns a Ford or Brown is in Barcelona.
Either Jones owns a Ford or Brown is in Brest-Litovsk.
Since (1) entails each of the propositions (2) through (4), and since Smith recognizes these entailments, his beliefs in propositions (2)–(4) are justified. Now suppose that, by sheer coincidence, Brown is indeed in Barcelona. Given these assumptions, we may say that Smith, when he believes (3), holds a justified true belief. However, is Smith's belief an instance of knowledge? Intuitively, Smith's belief cannot be knowledge; it is merely lucky that it is true.

58. From http://plato.stanford.edu/entries/knowledge-analysis/index.html
Most epistemologists have accepted Gettier's argument, taking it to show that the three conditions of the JTB account—truth, belief, and justification—are not in general sufficient for knowledge. How must the analysis of knowledge be modified to make it immune to cases like the one we just considered? This is what is commonly referred to as the “Gettier problem”.
Above, we noted that one role of the justification is to rule out lucky guesses as cases of knowledge. A lesson of the Gettier problem is that it appears that even true beliefs that are justified can nevertheless be epistemically lucky in a way inconsistent with knowledge.
Epistemologists who think that the JTB approach is basically on the right track must choose between two different strategies for solving the Gettier problem
From

59. Structure of the Counterexample
Reminder: Traditional account says JTB is necessary & sufficient for knowledge.
Question: What does this counterexample teach us about the JTB account of knowledge? JTB is…
(a) Not necessary for knowledge.
(b) Not sufficient for knowledge.
(c) Neither necessary nor sufficient for knowledge.
Structure of the Counterexample:
S has JTB
But: S doesn’t know that p
So: JTB is insufficient for knowledge
How to Proceed: S knows that p iff JTB + ?
Any guesses as to what should be added?

60. Nozick’s Tracking Theory (sensitivity conditions)
S knows that p iff:
p is true.
S believes p.
If p were false, S would not believe p.
If p were true, S would believe p.
Which is to say:-
s knows that p when the following conditions hold
p is true
s believes p
If p were the case then s would believe p
If p were not the case then s would not believe it

61. The Sheep Case (NTA): S knows that p only iff: p is true.
S believes p.
If p were not true, then S would not believe p. …
Question: Is condition 3 satisfied in the Sheep Case? That is, is the following true:
(A) If there were no sheep in the field, S would not believe that there are sheep in the field.
NO! I.e., S would still believe it.
So condition 3 is not satisfied.
So according to Nozick’s theory, one does not know that there is a sheep in the field. This is exactly the conclusion we want.

62. Imagine the following situation: (a) you are a brain in a vat stimulated by scientists who have fed you all your experience so far in life, (b) the scientists have made you aware of this, (c) you are familiar with Nozick’s tracking theory of knowledge.
According to Nozick, why is it still the case that your belief in the proposition “I am a brain in a vat” (call it P) will not count as knowledge?
Nozick's Tracking Theory S knows that P iff
(i) P is true
(ii) S believes that P
(iii) If P were false, then S would not believe that P.
(iv) If P were true, then S would believe that P.
(A) Condition (i) of Nozick’s Tracking Theory is not satisfied.
(B) Condition (ii) of Nozick’s Tracking Theory is not satisfied.
(C) Condition (iii) of Nozick’s Tracking Theory is not satisfied.
(D) Condition (iv) of Nozick’s Tracking Theory is not satisfied.