The Earth is flat

The support for the earth being a sphere is a combination of both direct and indirect observation.

1.) Images from space.

Multiple organizations that have sent rockets into space have all shown that the earth is curved. These pictures are from the ESA[1], Russian Space Agency[2], NASA[3] the ISS live stream[4], amateur rocketry organizations[5], non-governmental space corporations such as Space X[6] and James May, a former presenter of Top Gear [7].

Given the scope of these images, the quantity of the evidence, and the number of individuals (and associated technology) that must be dedicated to creating these images - the idea that this is all a massive conspiracy is not plausible. This is before considering that many images were created before modern photo editing software made high quality adjustments to images possible.

2.) Terrestrial images.

Multiple examples of terrestrial images reveal demonstrate that there is detectable curvature.

Power lines curving over lake Pontchartrain are a good example.[8]

These clearly show the power lines following the curvature of the earth over longer distances.

3.) Terrestrial observation

The best and easiest to observe facet of the earth not being flat, is the ubiquity of the horizon.

In all cases, boats, cities, objects frequently appear partially obscured by water when viewed from far enough away.[9][10][11][12]

On a broadly flat earth, with the waters surface being flat - there is no geometric configuration in which the water that is lower than the level of the building can appear higher.

Instead, what is being observed is the objects appearing behind the curvature of the earth.

4.) Days and Nights

At some point on the earth, it is day time, while night time for another. As there is no point in time where the entire earth is dark, if the were a flat plane, this would mean that the sun is above the plane - and thus the entire earth should be in daylight at all times.[13]

The pattern of 24 hour days, with time zones where different parts of the earth are in daylight whilst the opposite sides are in darkness is consistent with the earth being a sphere - and rotating at constant speed.

5.) The moon and sun travel at constant angular speed.

Both the moon and sun travel across the sky at constant angular speed. The sun specifically travels at around 15 degrees per hour. The moon travels a little faster.[14]

This is true at all times for all observes at all locations on the earth.

When an object moves over a flat plane, keeping constant height and constant speed. The angular speed compared to an individual on the ground is variable:

The apparent angle of the object is determined by its distance and height of the object from the observer - the angle governed by tan (height/distance). Given the tan identity, the change in angle produced by a change in distance is not linear.

IE, an object a 1 mile high, and 1 mile away, will appear at 45 degrees, once it moves 1 mile, it will appear at 26.5 degrees above horizontal, another 1 mile it will be 18.4 degrees above horizontal, with each movement, comes a different angular change.

This means that the apparent angle of the sun and moon could not change constantly to an observer on the ground without it changing height and speed.

If the sun and moon changed height and speed compares to one observer, another observer at another location would perceive a completely different change in angle.

As a result, this means the earth cannot possibly be flat and produce observations of the sun and moon as they are.

Sources.
  
[1]http://m.esa.int/spaceinimages/Images/2016/06/Spain_and_Portugal_photobomb
[2] http://en.roscosmos.ru/310/
[3] https://visibleearth.nasa.gov
[4] https://m.youtube.com/watch?v=Gy5PC5Auoak
[5] https://m.youtube.com/watch?time_continue=2&v=sQw_C5KLhFM
[6] https://m.youtube.com/watch?v=4jEz03Z8azc
[7] https://m.youtube.com/watch?v=jIJRoj2qwsc
[8]https://m.youtube.com/watch?v=kADO7nkt-rk
[9] https://goo.gl/images/MqX5z7
[10]https://goo.gl/images/XKr5Ww
[11] https://goo.gl/images/wK3qJD
[12] https://goo.gl/images/GEAZpu
[13] https://goo.gl/images/GEAZpu
[14] https://en.m.wikipedia.org/wiki/Sundial (apparent motion)

I thank my opponent for his quality response. I’ll be covering the points Con has detailed, directly following a concession.
I initially wrote some ten pages of response before deciding that I needed to make one key concession, for the benefit of this debate. I will present this concession first, then present the reformulation of my remaining points. (The reader will not see the original formulation, but it should be noted that everything you’re about to read is edited from another formulation and, as such, there might be some confusing statements.)
My Concession
I decided that it would be good for this debate if I accepted one of my opponent’s definitions for the BoP.
I initially was going to argue that the BoP requires absolutely nothing of me. That I essentially could remain silent and argue that the opponent has not sufficiently proved his claim. And while I do think this position is justified, in the context of the skeptical point I am trying to make, I must admit it isn’t particularly useful or educational.
So instead, I will give up some ground and use the opponent’s definition, “Unilateral BoP is a situation in which one debater has a special obligation to provide evidence for a position, whereas the other debater technically needs only provide evidence negating that position.”
My Evil Demon argument constitutes an evidenced negation, so I believe this concession will allow us to spend more time focusing on the philosophical aspects of this debate. If I did not make this concession, then the opponent and I could easily spend five rounds digging up increasingly obscure definitions to make our point. This would make for a valid, but boring debate, so best to avoid it.
Importantly, I am not implicitly accepting any extensions to that definition which may be present in the opponent's source.
0. “Pro concedes the entire debate.”
Con claims that, because I have rejected the notion that the Earth can be proved to absolutely have a shape, I have negated my own position, thus conceding the debate.
One must only refer to the now-accepted definition of BoP to see that I have no obligation to provide evidence that “the earth is flat”. In fact, I am “allowed” to believe it false. My sole obligation is in negating the opponent’s case, which I have done. Thus, nothing has been conceded.
1. Burden of Proof
This section, previously three pages in length, can now be countered in just a few sentences.
I have accepted one of my opponent’s definitions for the BoP. Under this definition, my Evil Demon argument constitutes a negation of my opponent’s case. Since we are now using an agreed upon definition, there is little else for me to say in this section.
The opponent can no longer argue that I am using some oppressive, unfair, absurd or punishing definition, since it is his. Any injury this definition has on the opponent is now utterly “fair”, since it is his definition.
Further, the opponent can no longer argue that I am using some notion of the BoP which is “out of context”.
We may need to return to this topic, specifically regarding this so-called “Standard of Proof” concept. A quick Google reveals this is a concept which seems to uniquely exist in the philosophy of law and is not generally applied to all manner of proof. However, I will not further justify this if not necessary. With my acceptance of the opponent’s definition, this may not be worth considering.
2. Evil Demon
The opponent makes a variety of arguments here.
A. “It concedes the entire debate.”
Again, refer to point (0). I have no obligation to offer evidence that the “earth is flat”, as per the opponent’s definition of BoP. I only have to negate the opponent’s case, which this argument does. (For reasons below.)
B. “It lacks any warrant.”
I demonstrated in the last round that my Evil Demon scenario is possible, immeasurably probable and mutually exclusive with the opponent’s case. (It holds that the earth does not exist.)
The opponent has not directly countered any of these facts. The mutual exclusivity constitutes clash and, further, negation. Both of our scenarios cannot simultaneously be true. It is evidenced via a logical argument which is, arguably, more compelling than any empirical argument, since it is fundamentally deductive rather than inductive in nature.
The opponent is now obligated under his BoP to demonstrate that my argument does not effectively negate his case.
C. “The inherent assumption of the Kritik is itself invalid.”
The opponent argues that if my position is correct, then everything is meaningless. If everything is meaningless, then no one should vote on this debate, or in fact debate or do anything at all.
The opponent opens a can of worms here. I grant that he is correct that, if my position is true, then nothing has any objective meaning. However, the opponent fails to appreciate that, if his position is correct, then we still have no reason to believe anything has objective meaning.
If his notion of the universe is correct, then we are all the product of some complicated physical and chemical reactions. We are particles bumping against other particles and there is still no means of ascribing life (or anything) any sort of “true” or “objective” meaning.
Subjectively speaking, things can still have meaning in either of our scenarios. The reader must admit that, even if they do exist at the whims of some Evil Demon, that they find meaning in voting for a debate. It is possible to admit the philosophical possibility that “nothing except myself is real” and simultaneously accept this and find personal purpose.
I maintain that both of our positions are equally as meaningless. Despite this, we will continue debating and the voters will continue voting. It is human nature to create meaning where none objectively exists.
Then the opponent’s rejection of my argument on this basis is flawed. We have no reason to believe anything has “objective meaning” or that his scenario is any more “meaningful” than my own.
D. “It’s not even relevant.”
This is my favorite argument that the opponent has presented, as it is the most philosophically interesting.
The opponent argues that the earth is real in some context, even if that context is imaginary or fictional. He then argues that, because there is some shared context in which it is round, he has proved his claim.
This argument is problematic. First, it directly implies that, while the Earth is round, it is also flat. There certainly exists a context in which it is round, but there also exists a context in which it is flat.
Consider that “Flat Earthers” are real. [1] In my scenario, the earth exists only in the context of their minds. This particular conceptual earth, existing in their minds, is certainly flat, because they believe it to be so. Their concept of earth assigns the planet the property of “flatness”. All flat earthers have arguments as to “why” their notion of the earth is correct. Thus, flat earthers have a shared context in which the earth is flat.
Similarly, there are those who, like the opponent, share a context in which the earth is round, complete with their own arguments.
My opponent’s argument would hold that the earth, then, is both round and flat. The reason that this is a problem is, for one, that it makes it impossible for either of us to lose this debate. In this context, my opponent would have “proved” his claim, and I similarly would have “proved” mine. Both of our positions would be “true”, in the sense of truth my opponent is arguing. What is a voter to do?
If the voter decides this argument is meritorious, then there cannot be a winner, since we’ve both proved our claims to the maximal extent possible. Perhaps this would even be fitting for a skeptical debate such as this. If the voter wishes there to be a winner, however, then this argument must be rejected. For a winner to be chosen, it is not enough to demonstrate that something is true in an imaginary context, but instead that the claim must be true in a “real” context.
That is, if we are assuming the voters wish there to be a winner, the opponent must prove that the earth is round in the physical context of the universe. This further implies he must prove that the earth exists in this way, as opposed to being a delusion brought on by the Evil Demon.
It is probably most useful for the debaters and the voters to reject this argument. If our standard of truth is “true is some context, even if imaginary”, then any debates regarding reality would be largely useless. Most everything is both true and false, depending upon context. Allowing for imaginary contexts effectively renders debate a pointless exercise. (Pointless in the sense that there is nothing to be learned from it.)
TL;DR Summary
While my concession has allowed me to shorten this response, I still think it will be useful to give a condensed overview of each of my arguments.
0. Pro concedes debate.
The opponent’s definition of BoP does not require I present any evidence that “the earth is flat”. I merely have to negate the opponent’s case, which I’ve done.
1. Burden of Proof
I accepted one of my opponent’s definitions, rendering this point moot.
2a. It concedes the debate.
See point (0).
2b. It lacks warrant.
The Evil Demon scenario is logically possible, immeasurably probable, and mutually exclusive with the opponent’s scenario. It thus constitutes a warranted negation of my opponent’s thesis.
2c. The Kritik is invalid. (Meaninglessness)
We have no reason to believe anything has objective meaning, in either of our scenarios. Subjective meaning exists in both scenarios and, thus, the voters will still be able to vote.
2d. It’s not relevant. (Multiple contexts)
If we accept that the opponent’s “it’s true in some context” argument holds, then neither debater can lose, since both debaters have proved their thesis according to this standard of truth. If the voters desires a winner, then this argument must be rejected, implying the opponent must demonstrate that the earth is round in a specific context, rather than just “any” context. We should prefer the latter scenario, otherwise we have effectively rendered most debate useless.
Final Summary
I hope that my mild concession has allowed this debate to become more focused on the philosophical issue at hand. By accepting this shared definition, many of my opponent’s critiques do not stand.
I have not provided positive evidence that “the earth is flat”, but the shared definition of "BoP" does not require me to. The opponent cannot simultaneously uphold his definition and demand that I have obligations not required by that definition.
I have negated the opponent’s case with the Evil Demon argument. The opponent must demonstrate this negation is either not an actual negation or that it is insufficient in order to win the debate.
Source
[1] - https://www.tfes.org/

I apologize to voters - Pros insistence at making an anti-social attempt to shift the burden of proof to such an extreme and absurd degree that its impossible to meet, is somewhat tying my hands. I would have loved this to have been a scientific discussion - however this has now become bogged down in dealing with pros tactics of trying to dodge his burden. 

0.) Pro negates the resolution. Concedes he negates the resolution.

The resolution is “The earth is flat”.

If pro - who is arguing affirmative - argues or proves that the earth is not flat, pro has negated the resolution - and pro loses the debate.

Pro isn’t claiming he didn’t negate the resolution, he is simply claiming that it doesn’t matter that he negated the resolution.

As a reminder, pros only argument stated:

Burden of Proof only matters if there is a dispute[1], if we both agree on a point no Burden of Proof is required any more as both side agree the claim is false.

The charging party has burden of proof in a trial - but if the defendant proves or admits his own guilt - he is still guilty.[2]

At this point voters have a pretty simply choice: Pros argument is that the earth is not flat. Cons argument is that the earth is not flat. This is an open and shut vote for the side that claims the earth is not flat.

1.) Burden of Proof

In a debate on some point, when one side has provided detailed evidence in support of their position - the other side cannot simply throw around absurd and unsupported speculation as pro does - and argue it is a genuine argument that refutes provided evidence.[3]

I pointed this out in the previous round. l detailed what the burden of proof actually means, and pointed out that pro completely misunderstands the meaning and intent. Pro dropped this entire argument in his previous round, and conceded that we should use this working definition:

As pro has dropped the remainder of the points about burden - he claimed I have beat infinite standard, and had to prove all other theories impossible: pro drops all of these - and thus conceded his claims here are false.

As I have provided evidence for my position in round 1 - I have met my burden of proof for this debate as per the definition. Pro accepts that he must provide evidence to negate my claims now that I have satisfied the burden of proof.

Let’s return to pros only argument he has made: Pro argues that if the earth doesn’t exist, then the earth isn’t a sphere (and also can’t be flat either - as noted).

The important word in this summary is the following:

If.

Let’s say that we accept this argument on its face: if the earth doesn’t exist, my position is negated, conversely if the earth does exist my position is not negated.

If there is some non zero possibility the earth doesn’t exist - it doesn’t negate my position: it merely implies that there is a non zero possibility my position is negated. 

Pro has to show that my arguments are wrong, which means pro has to establish - at the very least - that it is at least marginally probable that the earth doesn’t exist: pro must therefore convince voters that the earth doesn’t exist. Obviously, it is wildly irrational to assume the default position is that the earth does not exist, and so pro must provide evidence to move voters from the default position.

Pros argument here is asserted without warrant, he has not supported his position with any probability - and as the premise is absurd: pros argument is less valid than someone simply asserting a photograph was a fake, or that NASA was involved in a conspiracy: an even more patently absurd claim as pro makes requires even more justification.

Pro may continue to opine that I am required to disprove his claims here - but as he conceded - I only have to provide evidence for my position that the earth is not flat for my burden. The rest is on him.

2.) Whoops! Pros implicit concession #2

Pros entire prior argument completely misunderstood what BoP meant - and pro previously argued that I had an infinite standard of proof beyond any doubt:

Now that pro has conceded - by accepting the previous definition - that I don’t actually have to do any of the things he originally claimed I did, not only has he undermined the only argument he made as to why his position should be accepted: but his previous admissions about his argument demonstrate he can’t meet the burden he just accepted.

How can he convince voters that it is even marginally probable that earth doesn’t exist - if he himself admits no probabilities can be assigned?

He even went so far as to say:

Indeed, pro went to great lengths in his first round to tell us all how impossible it is for there to be any evidence for or against his position, and then claims:

Are voters expected to believe that the very thing you just said has no evidence for or against, nor can be proven or disprove is now something you have provided evidence for?

No. Pro has dug himself a hole where he implicitly concedes he has to show the evidence supporting the probability of his claim, after spending an entire round telling us all how no one is able to do that.

3.) Pros argument renders debate meaningless.

Pro seems not to understand the issue.

If pros whole argument is that objective and agreed meaning is impossible. His entire response to (4) was how there is no framework to agree on anything - and now appears to argue it’s quite possible to have a debate without that framework.

Pros whole position is that objective agreement is not possible - which he continues to affirm in this round with his argument about context. If that is the case then pro has essentially negated the possibility of this being a debate in the first place - or that debate is even possible - if a debate is not possible as agreement is not possible, then he cannot be deemed the winner.

4.) Context of earth.

You, me, flat earthers, all voters, and all human beings appear to collectively observe the same earth with the same properties. 

Even the flat earthers - which pro asserts without any evidence at all seem to agree on the observations that are being made[4][5][6][7] what they claim to see is what we also see, but disagree with the explanation.

It is this collective observation of the earth, that is obviously the obvious context of the resolution.

The Earth can’t be both spherical, and flat - it violates the laws of non contradiction[8] and the very nature of what being flat and spherical entail preclude it. [9][10]. This means if one earth is a sphere and one is flat - there is not a single objective earth, but multiple subjective earths.

The earth is either an objectively measurable and observable thing that all humans view and perceive or it’s not.

If it is - then it’s spherical based on the evidence mentioned in round 1.

If it is not, then there is no “the earth”, and merely a collection of conceptualized imaginations. As a result - as “the earth” doesn’t exist - it can’t be flat.

In both cases the resolution is negated.

Summary.

Quite frankly, pro is engaging in a ridiculous semantic argument, repeatedly attempting to shift the burden of proof.

He has completely mischaracterized what our burdens are.

At this point, it’s fairly clear that pro isn’t engaging in good faith, and likely appears to be simply trolling - as I don’t believe anyone who appears as cogent as pro would misunderstand burden of proof so profoundly by accident.

Here are the take aways.

1.) Pros argument negates the resolution. He didn’t contest this, so voters should conclude the resolution is negated and award the debate to con.

2.) Pro conceded definition shows that I have met my burden of proof. 

3.) To win, pro must provide an argument that convinces voters that the earth doesn’t exist. He offers no such argument.

4.) Pros argument is asserted speculation, pro concedes he must provide evidence for it, after spending his entire last round saying that there can be no evidence for it.

5.) Pro inherently misunderstands the issues with assumptions.

6.) The earth is either not flat because it doesn’t exist - or there is some common observed earth, which the evidence shows is not flat. Either way it is not flat.

Sources:

[1] https://www.collinsdictionary.com/dictionary/english/burden-of-proof
[2] https://en.m.wikipedia.org/wiki/Plea
[3] https://en.m.wikipedia.org/wiki/Hitchens's_razor
[4] https://en.m.wikipedia.org/wiki/Bedford_Level_experiment
[5] https://m.youtube.com/watch?v=zEqDbsPUgH8 (general observations)
[6] https://m.youtube.com/watch?v=17PFDyrweXg (general observations)
[7] https://m.youtube.com/watch?v=hqUXu8aZdsU
[8]  https://en.m.wikipedia.org/wiki/Law_of_noncontradiction
[9] https://en.m.wikipedia.org/wiki/Sphere
[10] https://en.m.wikipedia.org/wiki/Flat_(geometry)

Preface
I thank my opponent for submitting a response, but I’m not pleased with his sudden indignation or his implications. Con is attempting to paint my argument as some sort of unfair trickery.
The reader will note that in my previous round, I gave up ground by accepting the opponent’s definition of the Burden of Proof. The opponent cannot reasonably claim that I am “dodging my burden” and “shifting the burden of proof” when I’m using his definition. If the opponent is uncomfortable with the implications of his definition, then he should have considered offering a different one.
The opponent would like to claim I am acting in “bad faith”, when I gave in and allowed him additional ground. Not only did he get to define the rules of this debate, but I let him define the very definition which is key to my argument. Reject the opponent’s abuse claims as pathos rhetoric with the sole purpose of trying to emotionally manipulate the reader.
Second, do not pity the opponent for wishing this was a scientific discussion. Everyone knows what topic he chose -- he cannot seriously claim he did this “for science”. He was looking for an easy win. When confronted in the comments about the possible implications of a skeptical, philosophical argument, he rebuffed this as “probably ineffective”.
I have given him multiple opportunities to take control of this debate, be it warning him that the rules allow my argument or letting him define “burden of proof”. If he has squandered these opportunities, that’s his bad.
With that said, we’ll now cover the arguments from the opponent’s submission, following his order.
Arguments
0) Pro negates the resolution; concedes he negates the resolution.
The opponent’s argument boils down to this: The opponent [I] conceded that the earth is not flat, therefore the burden of proof no longer applies.
The sole justification for this argument seems to be based upon the legal system in the U.S., in which a guilty plea creates the circumstance where the trial for determining innocence does not occur.
The opponent would need to do a lot better in order to cross-apply this legal concept into this debate. The problems are myriad. First, we aren’t debating a legal topic. Second, we aren’t determining someone’s guilt. We aren’t even debating a binary issue -- each of us has a different claim and these two claims do not entail all possible scenarios. (The world could be neither flat or round, as a product of not existing.)
Reject the opponent’s claim that the BoP has “fallen off of him” and that he is no longer bound by it on the grounds that the opponent’s justification does not apply here.
Further remarks from the opponent here indicate that “BoP only matters if there is a dispute”. Recall that the opponent is claiming the earth is round and that I am negating this claim. This entails a dispute.
Next, recall that the opponent is not tasked with proving “the earth is not flat”. In his debate description, he clearly claims he’ll be arguing that “the earth is spherical”.
Finally, we must again appeal to the opponent’s definition of BoP. As per that definition, I am not responsible for proving my claim. This directly implies I am not even responsible for maintaining it. If the opponent did not assign himself the unilateral burden of proof, this would not be a problem for him. However, he did.
1. Burden of Proof
Con notes my acceptance of his definition of BoP, then moves into the more pertinent discussion of his obligations under his Burden of Proof, as he defined it.
We work backwards, from his conclusion, in order to most clearly see where his argument that he has satisfied his burden is fault. His conclusion statement is telling: “I only have to provide evidence for my position that the earth is not flat for my burden.”
I can understand why the opponent would like his position to be “the earth is not flat”. If this were his position, it would be difficult not to hand him this round. But this is not his position. Refer to the opponent’s debate description (which he wrote). He says, “Con arguing for a spherical earth.”
As I have noted, the earth is not necessarily flat or spherical. It might not exist, it might be a half sphere, or it might be shaped like a pointed Christmas ornament. There are many shapes besides “round” and “flat”, so we cannot assume the claims “earth is spherical” and “earth is not flat” are in any way equivalent.
The opponent does not get to “only” prove the earth isn’t flat; he has to further prove it is indeed spherical.
--------------
Another critical portion of my opponent’s argument surrounds his claim, “it is wildly irrational to assume the default position is that the earth does not exist.” He does not justify this in any way; it is an assertion.
Why should we assume the earth to exist by default? The entire purpose of my Evil Demon argument is to show that, not only is there the possibility that it does not exist, but that we further cannot assign probabilistic values to its likelihood. That is, we cannot make the claim, “It is more likely the earth exists than it does not.” And if we cannot make this claim, we certainly cannot say that we should assume the earth exists “by default”.
The opponent claims I have to show it is “marginally probable that the earth doesn’t exist”, and I have shown we cannot assume either scenario is more probable. In multiple rounds I have clearly stated that it was important to note that we cannot assign probabilistic values to our scenarios, and he ignores this, claiming we should just accept his assumption by default.
In summary, do not allow the opponent to get away with a weaker claim; he must prove the earth is spherical, not just that it isn’t flat. Second, do not allow the opponent’s assertion that earth’s existence is the “default assumption” if he does not provide any reason to believe this is the case.
For these reasons, the opponent has not yet satisfied his burden. He made an evidenced claim that “the earth is spherical”. I presented an argument which directly negates this. As of this point, he has yet to demonstrate that my argument is false, unreasonable or unlikely. If he cannot do this, he has not effectively rebuffed my negation, meaning he has not upheld his unilateral burden of proof.
2. “Whoops”
Here the opponent finally takes note of my “probabilities” argument. His argument boils down to this: “If we can’t assign probabilities, then how do we know the situation has a probability of being true? And if we can’t determine this probability of being true, how does this argument constitute an evidenced one?”
The opponent has created a sticky situation for himself by responding in the way he did.
The opponent had two choices in combating this argument. He could either claim that we can determine probabilities or he would concede that we cannot. He appears to have done the latter.
If we cannot assign probabilities to the situation, then we have no means of assigning a probability that the earth does exist. And if we can’t assign a probability to the likelihood that earth does exist, then how can we claim it is even marginally possible? If we can’t reasonably claim that it’s even marginally possible that the earth exists, then how does the opponent’s case constitute an evidenced claim?
If we are to accept that the opponent has conceded that we cannot assign probability values to our scenarios and buy his claim that this implies a total lack of evidence, then we must conclude that the opponent concedes his evidence is worthless, since he has not proved that it is “marginally possible” that it is true.
Of course, in this case my argument would be equally as useless. I would still win the debate, however, because the opponent would have an unevidenced claim while possessing the unilateral burden of proof.
In summary, the opponent assumes that my point regarding the impossibility of assigning probabilistic values to our scenarios was some mistake which would sink me. He then (implicitly) conceded that you can’t assign probabilities, rendering his entire case baseless, by his own argument. He renders my case baseless as well in doing this, but it only harms him, since he possesses the burden of proof.
Of course, since the opponent only implicitly conceded this, he is free to explicitly claim otherwise. In doing so, he would further need to show his scenario more likely than my own.
3. Pro’s argument renders debate meaningless.
The opponent asserts that my skeptical argument effectively render debate meaningless. This is because, “if objective agreement is not possible… [I have] negated the possibility of this being a debate in the first place - or that debate is even possible - if a debate is not possible as agreement is not possible, then he cannot be deemed the winner.”
There are a lot of assertions in there to unpack, but it is not necessary to do so. The reader is free to ask him/herself the following questions:
a) Are you reading a debate right?
b) Have you learned anything?
If the answers to those questions are yes, then you have convinced yourself that this is a debate and that it was not meaningless.
My entire argument revolves around the idea of epistemological doubt. Nothing can be “objectively proved to be true” that wasn’t ultimately based upon some sort of system of axioms. An axiom is something you assume to be true, but can’t actually prove. Even the system of mathematics is this way, only being true if you accept that some “basic rules” are also true (with absolutely no additional warrant.)
The is the nature of the limitations of knowledge. Nothing can truly, truly be known to be absolutely true and there is no way of objectively agreeing on any fact. Despite this, debate and discussions are tools which are critical to advancing human understanding of the world around them. Without debate, we would not ever have created numerous philosophical, legal, mathematical and scientific ideas we have now.
The opponent’s conclusion that the impossibility of “objective agreement” effectively neuters debate is insulting. We will never be able to prove something in an absolute sense, but that should never stop us from trying.
Reject Con’s pessimism.
4. Conext of earth
The opponent again mischaracterizes his resolutional obligation. He does not only have to prove “the earth is not flat”, but further that “the earth is spherical”. His rules in his description.
Thus, his argument boils down to “if the earth is real, then it is spherical. If it is not real, then it is not flat”. Even if this claim is true, it does not render him the winner. Proving it is not flat is not sufficient. He must prove it is spherical.
In both of our scenarios, the opponent would live in a world where everyone around him had the same physical experience of observing the same earth. In his scenario, he would actually be on a “real” earth with other “real” people. In my scenario, this earth and those people would be a delusion brought on by the Evil Demon.
Thus, I am still arguing within the context of the debate. My argument accounts for the apparent shared experience of the earth. This does not have further implications strengthening the opponent’s case.
Critical Question
I need to be extra clear here, as it’s important that the opponent address the following point if he wishes to win this debate on the grounds of a philosophical argument.
Why should we believe it is more likely that the earth exists than not? Can we assign a likelihood to it and, if so, how? Why should we believe, by default, that the earth exists?
If the opponent cannot answer these questions, then he has not demonstrated that this case has any more validity than my own. Do note that the opponent’s entire case rests upon the assumption that the earth exists and that it is this assumption which I am negating.
If the opponent’s case is no stronger than my negation, then I have won, since I do not possess the burden of proof.
Summary
I have accepted my opponent’s definition of the BoP and, immediately, he engages in rhetoric that I am treating him unfairly. I will not rehash what I said at the beginning of the round, but the conclusion was to reject his complaints. I have already detailed why my argument is fair and how the opponent had ample opportunity to avoid it.
Reject the opponent’s claim that I have mischaracterized our burdens; I have accepted his definition.
Reject the opponent’s claim that I am making semantic arguments; I have accepted and am using his definition.
Reject the opponent’s claim that I am not engaging in “good faith” debate. I accepted his definition of the BoP, even when I didn’t think it strictly necessary. I gave him additional ground and he responds by painting me as an unethical person. No good deed, I suppose.
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1. I have no obligation to uphold my claim, as per the opponent’s own definition of BoP.
2. The opponent resolutional burden is not to prove “the earth is not flat”, it is to prove “the earth is spherical”.
3. To win, the opponent must show that we have (significantly) greater reason to believe the earth exists than it doesn’t.
4. The opponent has not rejected my argument that the Evil Demon scenario is possible and of immeasurable probability. Thus, it constitutes a negation of my opponent’s fundamental assumption that the earth exists.
5. The opponent cannot be rewarded for claiming I “woefully misunderstand the BoP” when I have yielded to his own definition.
Key Takeaways
The opponent pivots most of his arguments to rest on the assumption that he merely needs to show the earth is not flat. This is not the case; he has a stronger resolution to uphold.
The opponent agrees that we cannot assign probabilistic likelihoods to our scenarios, rendering both of our cases worthless, defaulting the win to the one who does not hold the unilateral burden of proof. 
I look forward to my opponent’s response.

I thank Con for his response. Whereas this debate has apparently frustrated him, I’ve found it to be interesting and engaging.
I will be structuring this round differently, given that it is the final round. I will be making my case to the voters that I have won this debate, based upon everything that has preceded. While I will need to respond to a few of my opponent’s new arguments, I will not be making new arguments of my own.
I will first justify my position, in an ethical sense. I will demonstrate that my position is fair, that I have no engaged in “abusive burden shifting” as my opponent’s current rhetorical strategy insists, and I will finally demonstrate that this debate has been more educational and useful than if I had been arguing my case on traditional, scientific grounds.
We then briefly discuss resolutional burdens, as this has somehow become an issue of contention. (Though an important enough issue that it warrants its own section.)
Next, we’ll cover the main arguments in a high level way. The intent here is to show what has been argued thus far in a condensed formats. This will include new and continued arguments from the opponent as well as my responses.
Finally, we’ll look at voting issues, where I’ll attempt to convince the voter’s not just that the opponent cannot be given the win, but that it must be given to me. Note that the Conduct point will be argued in the justify section.
Justification
The purpose of this section is to justify my argument, ethically. I will demonstrate that the argument was fairly presented and is not abusive. The opponent has taken a hardline abuse position. While these rhetorical strategies aren’t particularly interesting, they are every debater’s right. I have covered all of what I’m about to say before, but I’m now putting it all in one section.
Is my argument a “gotcha” argument and did I “derail” the debate? No. Refer to the comment section, where I told the opponent (before accepting) that a skeptical argument would likely be effective here. The opponent rejected this idea. Thus, the opponent had every reason to suspect that I would be making a skeptical argument.
It is clear from the context of the comment section that I would be making a “Brain in the vat” argument and the opponent had no problem with this until the argument was actually applied against his case. If the opponent did not want to debate a “Bair in the Vat” argument, he merely had to say so. A simple, “That type of argument is not what I’m looking for here,” would have sufficed. The opponent failed to do this.
Because he had reason to suspect I’d be making this argument and failed to do or say anything about it, it cannot be said I have derailed this debate. In fact, I acted exactly as should have been predicted based upon the comment section. Because my argument was expected, it is additionally fair.
My case would have been a “gotcha” case if this comment section conversation had not occurred. But again, had it not occurred, I would not have taken this case.
The opponent had reason to suspect I’d make this argument beforehand and was given the opportunity to change the debate or otherwise declare he’d like more “traditional” arguments. He did not take this opportunity.
This case was not malice on my part, but hubris on the opponent’s part.
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The next ethical cornerstone of my opponent’s argument is this idea that I have continually shifted the burden of proof. We note that, after R1, I accepted the opponent’s definition for BoP and did not attempt to further change it, or even assume a different interpretation.
We return to this issue later, in “Justification -- Revisited”. We delay this discussion so that it can appear after we have considered the arguments of the debate.
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Finally, one more thing must be said. The voter is encouraged to note that this debate concerns the shape of the earth. If I presented more traditional arguments, the likes of which the opponent claims he was expected, then the opponent and I would be debating about whether the earth is flat or spherical.
The opponent is apparently an intelligent and educated person. I assume he is scientifically literate. How can the opponent reasonably claim I am running a “gotcha” argument when he’s attempting to debate what is, scientifically, one of the most obvious facts out there?
This topic cannot be reasonably debated as a scientific topic. Only the philosophical option allows both debaters ground.
If the opponent was looking for a scientific debate, then he is the one running a “gotcha” case. If he is frustrated that I made a philosophical argument, then he is frustrated that he didn’t get the easy win he was looking for.
The opponent’s abuse argument here is essentially, “I wanted to debate one of the most well-established scientific facts out there and my opponent has the audacity to argue on non-scientific grounds.”
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This leads into my next point. This debate is more valuable and educational than the debate which would have resulted if I had not made a philosophical argument.
This debate highlights the importance of not placing the Burden of Proof entirely on one debater, even in silly topics. I can claim with certainty that this debate has been educational, since I myself have learned something from my opponent’s case.
The claim, “The Burden of Proof should not be placed without limit on one side, unilaterally” is implicitly being argued here and this is an important and potentially controversial issue.
On the other hand, debating the scientific status of the shape of the earth makes for a completely useless debate. While the shape of the earth is socially controversial (for some reason), it is not scientifically controversial. A scientific debate on this issue is not valuable and is not education.
Thus, voters should prefer my philosophical argument over the “scientific argument” for a flat earth. The former allows us a rich and thorough debate, while the latter provides only for the most boring of circuses.
Resolutional Burdens
In the speech before my opponent’s most recent one, he quite suddenly began arguing that he was debating the resolution “the earth is flat”. I pointed out that, as per his own debate description, his resolution was actually, “the earth is spherical”.
Many of my arguments have been predicated upon the assumption that my opponent and I are debating two different resolutions and, throughout this debate, I have been debating based upon that assumption. This assumption is reasonable, because it’s exactly what the opponent stated in his description.
The opponent recently claims I am “only bringing this up now”. He sees this as deeply “unfair” and he doesn’t feel he has time to respond.
Ignore these abuse claims. The opponent’s opening case positively argued for a spherical earth. Up until R3, the opponent had apparently been debating according to his debate description. Obviously I did not need to point out his resolution burden until R3, since it wasn’t until R3 that he decided to go against it.
I did not “wait” until R3 to point this out -- it simply didn’t become an issue until Round 3. The opponent now suggests that his debate description is simply a “suggestion” for what arguments both sides “might” make. This should be rejected. The opponent does not present these as “suggestions”, but instead as our de facto resolutions to-be-argued.
Again, my entire case assumes that we are debating two different resolutions. The opponent cannot simply say, “Haha, I really meant that description as a suggestion,” and get away with it. The opponent did not present these resolutions as suggestions, nor did we have any reason to assume they were merely suggestions. The voter should then treat them as if they are indeed the resolutional burdens.
Arguments
Here, we will offer an overview of the central argument in this debate. This is not necessarily presented in round order.
Before we get started, we should make one note that has been leading to some confusion this round. The opponent is arguing for the resolution “the earth is spherical”. I am technically arguing for the resolution “the earth is flat”. We are arguing two separate resolutions. Additionally, my only obligation to provide evidence is to negate the opponent’s case.
This is actually a somewhat illogical situation. I have a resolution to uphold, but I simultaneously don’t have any obligation to provide evidence for it, as per the opponent’s definition of BoP. How does one uphold a resolution and also have no burden for upholding it? My implicit assumption on how to deal with this was simply that I didn’t have to argue that the earth is flat. I only had to negate the opponent’s case that the earth is spherical.
Thus, it is reasonable that my argument does not support the claim, “the earth is flat”. The BoP does not demand I prove the earth is flat. If I don’t have to present evidence for that claim, why should I have to uphold it?
Consider this central issue to be a contradiction which inherently exists in the framework of the opponent’s case. He gave each of us a different resolution, then enforced a unilateral burden of proof which doesn’t require one side (mine) to actually uphold the resolution.
Thus, if I effectively negate the opponent’s case, I have upheld my obligations under the BoP. The fact that my case clearly denies the existence of a flat earth does not somehow render this a “draw”, since my sole obligation is negating the opponent’s case.
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In the beginning, the opponent argued that the earth was spherical. He had five arguments for this. Each of these arguments were based upon a common assumption: The earth exists.
Opponent’s Contention: The earth is spherical because of this evidence. This evidence assumes that the earth exists.
My Evil Demon argument, amongst other things, demonstrates the possibility that the earth does not exist. Further, it argues that we have no means of determining likelihoods of the earth’s existence. Then my argument makes the assumption that the earth does not exist.
Current Contention: Con asserts the earth exists, with no evidence. Pro asserts the earth does not exist, with no evidence. Pro demonstrates that we cannot establish which position is more likely.
At this point, I have been arguing that the opponent needs to either provide evidence that the earth exists or demonstrate that this is a more reasonable or more likely position. In other words, we need reason to believe his assertion is more valuable than my own. Much of the “burden shifting” my opponent has been perceiving is in not understanding that this is my argument. My position is an assertion that the earth does not exist. But my Evil Demon argument demonstrates that his position is also an assertion. We are both currently making unwarranted assumptions.
Important Issue: This warrants repeating -- this is the source of much of the opponent’s perceived burden shifting. I am not attempting to prove that the Evil Demon scenario is true. Instead, the Evil Demon scenario reveals that the opponent’s assumption regarding the existence of the earth is fundamentally unprovable. That is, the Evil Demon scenario does not exist as a thing which should be proved, but instead a thing which reveals the impossibility of determining a “truth value” for claims such as “the earth exists”. My case argues that it is impossible for the opponent to uphold his resolutional burden. (See my argument response to his “debate is meaningless” to see why this does not apply to all debates.)
In the previous round, the opponent offers us a few reasons to assume that his assertion is more reasonable than my own.
a) “The earth’s existence is implicit in the resolution.”
See the “Justify” section in which I detail how the opponent was made aware of the possibility of my argument in the comment section and given the opportunity to modify the debate. The opponent knew I was going to make a “Brain in a Vat” argument and did not change the debate or ask that I do not. Thus, my not making any modifications (and by further deriding the argument as likely to fail), the opponent implicitly accepted that my “Brain in a Vat” argument would be within the grounds of the resolution.
The “Brain in a Vat” argument does not require the assumption that the earth exists and, often, claims it does not.
If we look at the resolutions alone, the opponent is correct. Given the additional context of the pre-debate comment section, it is clear this implicit assumption is off the table.
b) “Even if the earth is factually flat, I am at least presenting evidence it is spherical and this evidence has not been negated.”
This argument looks at the five points the opponent originally presented which I have not touched. The opponent fails to realize that I am negating his implicit assumption that the earth exists. His entire case is predicated upon this assumption.
Thus, we cannot say that I have not negated his evidence. By negating the claim that the earth exists (or rather, by showing my opponent’s evidence of this assumption is not sufficient), I am also negating his case.
I have directly negated the opponent’s evidence by showing it is based upon an unwarranted assumption. Unless the opponent shows this assumption warranted, his case falls.
c) “If the Earth’s shape is a shared delusion, then it can be considered spherical.”
My opponent incorrectly states that I dropped this argument. The reader will note that I argued that it is not a shared delusion. Many people believe the earth is flat. (They have even formed a society.)
Because it is not a shared delusion (and indeed even if it was), it is not meaningful to assign properties to this delusion. This is my argument regarding objects having multiple truth values in different contexts. If we are only claiming things have to be true in “some context”, then the opponent and I have both upheld our resolutions. There are some people who hold the shared belief that the earth is flat. In this context, the earth would be flat. Similarly, some believe the earth is spherical and, in this context, the earth would be spherical. Clearly, then, any object could have any number of mutually exclusive properties, simply because there is a context or potential context in which that property holds.
I rejected this argument last time because this standard of truth is too weak. If we only need to prove claims “in some shared context”, then most all claims could be proved both true and false. You literally just need two people to agree on some silly fact and, voila, shared context.
I did not drop this argument. The shared context implying truth standard is too weak -- it allows most everything to be considered both true and false, leading to pointless debate.
d) “Occam’s Razor says.”
The opponent claims that Occam’s Razor applies here, indicating the earth’s existence as the default position.
This situation does not allow the application of Occam’s Razor. One is not more simple than the other. See:
My Claim: The earth does not exist, but then something else, like a Demon would have to.
His Claim: The earth does exist.
Both of us are claiming that a thing exists. Further, both of us are claiming that a single thing exists. One situation is not “simpler” than the other. Thus, Occam’s Razor cannot be applied.
Recall that Occam’s Razor is the assertion which essentially claims that the simpler situation is more likely the correct one. The opponent has not convinced us that his assertion that “the earth exists” is any more simple than the assertion that “the earth does not exist”.
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At this point, the opponent and I are still upholding assertions. The opponent’s arguments that his position should be considered the “default” position have been demonstrated as insufficient.
Then my case is an assertion which I cannot prove. The opponent’s case is an assertion which he cannot (or at least has not) proved.
Based upon this, it is easy for the voter to conclude that the opponent has not met this burden of proof. Him and I have made mutually exclusive assertions of equal strength. We have no reason to prefer his assertion over my own.
Were the BoP shared, this situation would require a draw. Neither of us has proved our assertions. However, the BoP is not shared. The opponent has the obligation to provide sufficient evidence for his claims and, at this point, we are only left with the assertion that the earth exists.
This is the fundamental argument of the debate. This is what the opponent tasked himself with proven. He has left us with nothing more than an assertion. The debate must go to Pro.
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His Kritik - Debate is Meaningless
I would be remiss not to address his Kritik. I love his Kritik, not because it has the correct conclusions for all debate cases, but because it has the correct conclusions for some debate cases.
I am not arguing that every debate will ultimately be limited because of our fundamental inability to absolutely prove anything. I am arguing that this debate is limited.
Any debate in which one side accepts the unilateral burden of proof without also providing themselves basic axioms which they are “allowed” to assume true is a debate in which the person owning that burden must lose.
The unrestricted unilateral burden of proof is too strong a burden in any debate. It is because of this fact that I accepted this debate. Explaining this point was the purpose of my argument.
All debate is not meaningless and not all debates cannot be meaningfully resolved. Instead, this specific type of debate is “meaningless”. (In that, if both sides perform optimally, the side without the burden should always win.)
The opponent has repeatedly claimed that I do not “understand” the burden of proof. I maintain that my argument was made precisely because he, and others, do not appreciate what this burden entails. The Burden of Proof is an exceptionally powerful obligation. If one side of a debate receives too much of this burden, their position becomes fundamentally untenable.
This includes debates on ridiculous topics, like this one.
Justification -- Revisited
I enjoy winning debates, but I also see that it is important to admit when one has made mistakes.
My argument throughout this debate was fairly unfocused until R3. Initially, I was going to argue that my opponent had a sort of infinite burden of proof. After realizing that this would not create interesting debate, I accepted his definition. In R2, I was arguing that my opponent needed to somehow disprove my Evil Demon scenario, when my own argued maintained this was impossible.
As of R3, I argued that my Evil Demon scenario highlights the fact that both my opponent and I are making assertions regarding the existence of the earth and that there is no default position on which is true. This is the position I still uphold.
I apologize for the confusion and, to some degree, I understand the opponent’s frustration. However, as of round 3, my argument was focused and clear. The opponent then had his R3 response to cover this focused argument, which he only spent a little bit of time doing.
The opponent wishes to convince you that I have been unfairly shifting the burden. And in the first two rounds, I was shifting the burden. However, I was not doing this out of malice. I was attempting to refine an argument which I had never made before, applying it to an unusual topic.
If my point had not been crystalized by the end of R3, then clearly the opponent should be given the win, as crystallizing the argument here would be too late. However, by R3 my argument was clear. The opponent had some 35,000 characters to say whatever he wanted about it. He only had one speech to make his argument, but this speech had the capability of being as long as he wanted.
The opponent, despite having all this room, spent the majority of his time complaining that my argument was unfocused until R3 and less time actually rebutting the argument. (The time he did spend rebutting this argument are discussed above.)
In conclusion, I sympathize with my opponent and admit that my argument was unfocused prior to R3. The building blocks of my inevitable point were there, they just weren’t crystal clear. This was not out of malice, so the conduct point should not go to Con. The opponent still had ample time to respond to my focused argument, so no abuse is present.
The opponent deserves a pat on the back for dealing with me the first two rounds as I attempted to refine my argument, but he still had plenty of time to debate after it was finally made. Thus, no points should be awarded to him on these grounds.
Voting Issues
The opponent’s case is predicated upon the assertion that the earth exists. My Evil Demon argument reveals that a) this is indeed an assertion and b) that there is not way of determining which assertion is more likely. To win, the opponent would need to prove that his assertion that “the earth exists” is stronger than my assertion that “the earth doesn’t exist”.
The opponent fails to do this. He made a few arguments, but they were not strong enough to convince us that “earth exists” is the valid default position. (Recall that he ran shared context, Occam’s Razor, and resolutional implication.)
Because the opponent has not demonstrated it is any more likely or reasonable to assume the earth exists than doesn’t, he has not upheld his burden of proof by demonstrating the earth is spherical.
The opponent’s resolution is, “The earth is spherical”, as per his own description. We have no reason to believe this was only a “suggestion” or that he otherwise should not be bound by this.
My resolution is, “The earth is flat”, but the opponent’s definition of BoP doesn’t actually require me to uphold this resolution. I merely have to show that he did not provide sufficient evidence to uphold his own resolution.
My argument was expected and able to be mitigated before starting the debate, thus it cannot be considered a “derailment”, “in bad faith”, or “abusive”. My arguments created a debate of greater educational value than it would have been if I’d made the “scientific response”. If any voter is really a stickler for abuse, consider penalizing the opponent for being an intelligent person who decides to argue that the earth is spherical, as if any serious scientific debate could possibly follow.
My argument holds that the opponent’s position is fundamentally untenable because he placed too great a burden on himself. Not all debates are fundamentally untenable, however, as the burden of proof can be shared, to varying degrees, between participants.
Conclusion
I apologize for the unfocused argument, but since R3 I believe everything has been clear. The opponent asserts that the earth is real. I assert the earth is not real and, further, that we cannot determine which scenario is more likely. The opponent was not able to determine which scenario was more likely either, rendering us unable to choose a default position.
Thus, all the voters are left with are two sides making assertions on an issue which has no default existential position. Because the BoP is on Con, he failed to uphold the burden by presenting anything more compelling than an assertion. Thus, the round must go to me, Pro.
While my argument was unfocused, it was not out of malice. I am hopeful that it is obvious to the voter that this is the case. My only concern was in highlighting the limitations of knowledge and the implications this has on debates where one side has the unilateral burden of proof. The comment section discussion with the opponent led me to believe this argument was entirely acceptable and that I would not be catching him by surprise or otherwise attempting to trick him. Thus, the conduct point cannot be given to my opponent either.
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In fact, I am tempted to argue that the conduct point should go to me. The opponent has been claiming throughout the debate that my position is fundamentally flawed. (Of course, that’s largely what debate consists of.) If this was this case, it should have been no great feat to defeat my arguments.
Then it is unclear why the opponent decided to pepper in all the insults he did. He described this debate as “lacking merit” and he repeatedly attempt to paint what was clearly just an unfocused argument as some extreme case of abuse. Some 20% of the last two rounds have been him screaming the word “abuse” and deriding my character.
Again, if my argument was so unfounded, it should have been trivial to dispatch it. There was then no need for the insults, for the dramatic abuse cries and for the accusations. Certainly, there was no need to describe this debate as a “farce”. (Especially given that his idea of a non-farcical debate is one concerning the shape of the earth.)
We are left to conclude, then that the opponent engaged in this rude, deriding, and accusatory style of rhetoric as a strategy. He wanted to bolster the strength of his case by trying to paint his opponent as some sort of unethical monster who is fundamentally trying to ruin debate for everyone. Perhaps it is a product of our current political environment that these rhetorical strategies are used, but they are nonetheless shameful. You do not need to deride your opponent in order to be effective in a debate.
Thus, the conduct point should be awarded to me. If you have ever participated in a debate where your opponent implied you were in some way incompetent and that this debate was a waste of their time, and that made you feel badly, then indicate that this is not okay by taking the conduct point away from the opponent.
The sooner we get rid of the “Let’s not forget that my opponent is stupid,” argument, the better off debate will be.
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I thank the readers their patience and their time. This had been a very long debate, but hopefully something was learned. If anyone learned anything, then this debate has been for good.
Thanks again.