Philosophical Arguments (WritePhilosophy Guide)

Philosophical Arguments (WritePhilosophy Guide)

The first step to writing a good philosophy paper is to understand what a philosophy paper is. Fortunately, unlike most philosophical problems, we have a simple answer to that question. Quite simply:

A philosophy paper is an argument for a thesis.

We’ll say more about what an argument and a thesis are below. But the next step is to understand what makes a philosophy paper good. There are many things that affect how a reader will judge your paper. Some are unique to the psychology of that reader. But a philosophical reader, attuned to the norms and standards of philosophy, judges a paper primarily by one standard: how good is the argument for the thesis? In other words, they’re asking how well your paper does the job of being a philosophy paper.

The most important thing in writing a philosophy paper, then, is to make the strongest, most convincing argument for your thesis that you can. Everything else is window-dressing.

An argument for a thesis

Now that we know what a philosophy paper is, we can explore that definition in more detail to figure out what makes a philosophy paper good. The first thing to note is that the definition is given in the singular form. It’s an argument for a thesis. Not some arguments for a thesis, or even some arguments for some theses. The archetypal philosophy paper advances a single claim, its thesis, and devotes the entirety of the paper to convincing the reader of the truth of that claim.

To be sure, some of the best philosophical papers don’t do exactly this. They demonstrate multiple theses and offer a host of arguments in different directions. But these are papers written by remarkable philosophers whose skills have been finely honed and who can break this golden rule without scuppering their argumentative power, like a virtuoso musician who plays in ways no one else can, or a chess grandmaster who knows just when to do the unexpected to turn a match on its head. To put it another way, those papers are good despite the fact that they don’t offer a single argument for a single thesis, not because of it. Unless you are Wittgenstein, don’t try to write like Wittgenstein…


Your philosophy paper should articulate a single thesis, and use a single line of argument to persuade your reader of it. Because you have only one thesis in your paper, you might hope that it’s a good one! What exactly is your thesis?

Your thesis is a single sentence which you will defend throughout the paper. It must be a declarative sentence. It is not a question. Rather, it is probably an answer to some question. If the prompt for your paper is a question such as “Is active euthanasia morally permissible?”, then your thesis might be a direct response to that question, like: “Active euthanasia is morally permissible.” It also should not be an order or instruction. Imperative sentences such as orders are not defended by arguments. For instance, rather than “Do not perform active euthanasia”, your thesis would be something like: “Doctors should not perform active euthanasia”. Your thesis is a proposition, not a question or instruction.

Your thesis must be a declarative sentence because only declarative sentences can be the conclusion of a logical argument. You can think about your thesis as the conclusion of the argument which you are making. This can be challenging: after all, how do you know what argument you are making unless you know what conclusion you are trying to demonstrate? Many writers start with a thesis they want to prove, then construct the argument working backwards from there. But, as we’ll see, it might turn out that what you wanted to prove and what you are able to prove with your argument are different. In that case, your thesis must be what you actually argue for, not what you wanted to argue for. There is no shame in defending a less ambitious, more specific thesis, or in defending a thesis which you originally did not believe to be true. A hallmark of philosophy is going where the arguments take us, without attachment to principles or ideas which have not been rigorously demonstrated by logical argument.

Your thesis must be what you actually argue for, not what you wanted to argue for.

For most philosophy papers, if you cannot state your thesis as a single sentence, your paper is too complex or you simply have not yet chosen a specific thesis. It’s fine if you need a few more sentences to explain your thesis (perhaps by defining terms or contextualising it), as long as it can be stated in one. A thesis statement is always a single sentence, but it can be quite a complicated sentence. Consider, for example the following thesis:

“If Abrams’ objection to James Rachels’ argument is invalid, then active euthanasia is morally permissible if and only if the patient is able to actively and autonomously consent to the procedure and the patients’ life is irreversibly not worth living as judged by the patient themselves.”

Or this:

“Either scientific realism is true or the success of scientific theories in allowing us to predict novel facts about our universe cannot be explained.”

The first thesis here is in the conditional form – an ‘if … then …’ statement (see below for more detail). The second is in disjunctive form – an ‘either … or … ‘ statement. This is perfectly permissible, as long as this is precisely the claim for which you are arguing. Indeed, you will often find that it is almost impossible to argue convincingly for broad, general claims like “Scientific realism is true” or “Active euthanasia is morally permissible”. Good philosophers will find themselves narrowing their thesis by adding qualifiers (e.g. ‘if and only if the patient is able to actively and autonomously consent to the procedure’). Again, this is not weakness, it is a strength of your paper: precision about what you are and are not defending is the only way to ensure that you will convince your reader.

The scope of your thesis usually matches the length of your paper. In a short paper, you won’t be able to defend a broad, general claim. Rather, you will make a small inroad towards a defence of that larger claim. If you are interested in whether active euthanasia is morally permissible, but are writing only a 1,500 word paper, your thesis might relate to a specific objection to an argument for the permissibility of euthanasia. For example: “Abrams’ objection to Rachels’ bathtub case fails to undermine the validity of his argument that the distinction between killing and letting die is not morally relevant.” If you were writing a 70,000-word book, on the other hand, your thesis’s scope might be much larger.

When writing a philosophy paper for a course, in response to a prompt or question, you will need to show the relevance of your thesis to that question. If the question was “Is active euthanasia morally permissible?” and your thesis relates only to Abrams’ objection to Rachels’ argument that the distinction between killing and letting die is morally irrelevant, then you need to do some work to explain why that matters to the question. Why is the distinction between killing and letting die pertinent to the moral permissibility of euthanasia? Why is Rachels’ argument relevant to that distinction? How does Abrams’ objection relate to Rachels’ argument? It may be that a significant portion of your paper is devoted to explaining why and how your thesis relates to the question at hand. Generally speaking, this is fine and expected. Do not let the generality of the question trick you into thinking you must defend a very general thesis! This is luring you down the path of writing a weak paper, in which you are unable to fully convince your reader of your thesis because you don’t have the space to demonstrate such a sweeping claim. Think of your defence of your thesis as a contribution towards the wider philosophical literature which, taken together, might allow us to answer the question.

Most of the time, your thesis will evolve over the writing process. When you first start out on your paper, you might only have a broad sense of what you want to argue. You might know that you think Rachels’ argument that the killing/letting die distinction is morally irrelevant seems very important to the permissibility of euthanasia, and be convinced by his argument. So your initial draft thesis might be something like: “Rachels’ argument that the killing/letting die distinction is morally irrelevant proves that active euthanasia can be morally permissible.” How would you prove that claim? You’d need to show that Rachels’ argument works. But to do that, it seems you’d need to dispense with all of the possible objections people could have to Rachels’ argument. That seems like too much to achieve in 1,500 words (and it is!) Perhaps, as you do more reading and writing, you find that it’s Abrams’ objection to Rachels’ argument which is giving you the most trouble in defending that claim. But you think you have a convincing response to Abrams that dispenses with her objection while leaving Rachels’ original argument intact. The only problem is that to explain Rachels’ argument, Abrams’ objection, and your response, is going to take the entire paper! No problem. Modify your thesis to focus only on showing that Abrams’ objection fails. Again, do not fear this refinement process: it is a good sign.

A more vexing question that we’ll have to bracket is what makes a thesis philosophical. A thesis could be purely factual, empirical, such as: “The average weight of a mute swan is 10kg.” This is not going to be the thesis of a philosophy paper – but might be the thesis of a particularly niche piece of ornithology. Generally, the thesis of a philosophy paper won’t be a scientific claim about the world, like that one. We might postpone the question by saying that a philosophical thesis is a claim which is relevant in answering some philosophical question. A premise in a philosophical argument for some philosophically-important claim. We’ll talk more about the range of philosophical questions in the Areas of Philosophy guide.


Your philosophy paper stands or falls primarily on whether you successfully persuade your reader of the truth of your thesis. Your argument is your tool to achieve this. Formally, an argument is a series of premises and a conclusion. Each premise and the conclusion must be declarative sentences. There can be many premises, or just one. When we present an argument, we make the claim that the conclusion follows (in some sense – much more on that to come) from the premises. Arguments come in many shapes and sizes but they all share that same basic structure:


Therefore, Conclusion

The word “Therefore” signifies the transition from premises to conclusion, and embeds our claim that the conclusion follows from the premises. In day-to-day writing, we could also use ‘thus’, ‘ergo’, ‘so’, etc. – but for simplicity, always stick to the philosophical convention and use ‘therefore’.

Here’s an example of an argument:

If God is all-powerful, then he could prevent evil. If God is all-loving, then he would want to prevent evil. So, God has the means and the desire to prevent evil. But evil exists. Therefore, there is no all-powerful and all-loving God.

We can break this down into the premises and the conclusion. The conclusion comes after the ‘Therefore’: it’s “There is no all-powerful and all-loving God”. The premises could be:

  1. Evil exists
  2. If God is all-powerful, then he could prevent evil.
  3. If God is all-loving, then he would want to prevent evil.
  4. An all-powerful, all-loving God has the means and the desire to prevent evil.

Four premises. If we look closely, we see that premise 4 as presented here is written as: “So, God has the means and the desire to prevent evil.” We know that ‘so’ is one of our synonyms for ‘therefore’. And indeed, what is happening here is an argument-within-an-argument. From premises 2 and 3, we can infer the truth of premise 4. So the broader argument has a mini-argument within it, namely:

1. If God is all-powerful, then he could prevent evil.
2. If God is all-loving, then he would want to prevent evil.

Therefore, an all-powerful, all-loving God has the means and the desire to prevent evil.

We also had to clarify that conclusion – in the original argument as laid out in plain text, it was left implicit that ‘God’ is all-loving and all-powerful. But there might be other kinds of God – so we state that explicitly in our logical formulation.

Technically, we don’t need to state premise 4 in our formulation of the argument, because the conclusion follows from premises 1, 2 and 3. We like to remove any redundant premises because they could be a source of criticism, while not being necessary to the argument. But spelling out the intermediate step, the mini-argument within the broader argument, can be helpful in bringing the reader along with you, though. We could state our full argument as:

1. If God is all-powerful, then he could prevent evil.
2. If God is all-loving, then he would want to prevent evil.
3. Evil exists.

Therefore, there is no all-powerful, all-loving God.

But there are a few holes in the reasoning. For instance, we might ask whether it follows from God having the means and desire to prevent evil that he would have gone ahead and done it. After all, there are plenty of things that we have the means and desire to do which we don’t do! To avoid that trap, we might add a new revised version of the old premise 4:

4. If God has the means to prevent evil and wants to prevent evil, then God would prevent evil.

Now, that fourth premise is no longer redundant – it is adding something new that we didn’t get from the first three premises, namely the requirement that for God, means and motive to prevent evil are sufficient for him to act.

This simple argumentative jiu-jitsu isn’t enough to avoid the problem, it merely makes it explicit. Anyone who might disagree can now clearly see that there is an avenue for objection: to show reasons why God might not prevent evil even though he could do it and wants to do it. If this was the argument we were making in a philosophy paper, we’d probably have to focus a lot of attention on defending that fourth premise.

A persuasive argument for a thesis

Our philosophy paper is an argument for a thesis. So, our philosophy paper, in a very real sense, is a series of premises and a conclusion. But it won’t be enough to simply state the premises and conclusion. We want the reader to be persuaded by our argument into believing that our thesis (the conclusion) is true. This gives us a golden rule for writing philosophy papers:

In order to persuade a reader of your thesis, they need to accept two things:

1. That the conclusion follows from the premises.

2. That the premises are all true.

Every good philosophy paper achieves these two things. This is about crafting an argument in which the conclusion follows from the premises, and about defending your premises to the point that the reader is persuaded to accept them. If your argument is deductive, this is the same as saying that your argument is sound.

Sometimes we need to demonstrate that the argument works by showing that the conclusion does indeed follow from the premises. In the next article in this guide, on validity and soundness, we’ll talk about one approach to doing this. If your reader looks at your premises and conclusion and can see a reason to doubt that the conclusion actually follows, then they are unlikely to be persuaded, and the battle is lost. That was what happened with the first version of the Problem of Evil argument above – there was a way to accept all of the premises while still denying the conclusion (namely, to say that God might have the means and the motive to prevent evil, but not do so for another reason). Usually, you want your argument to be watertight, so that the conclusion follows indisputably from the premises. But that’s not always the case – we’ll talk about some interesting forms of argument where the conclusion does not indisputably follow from the premises in the article on inductive arguments.

We also need to demonstrate the truth of each of the premises! After all, your reader is hardly going to be convinced by your argument if they think one or more of the premises is false. That would give them a very easy reason to disregard the entire paper.

How do you defend a premise? By showing that it is true. Some premises are uncontroversial, accepted by everyone involved in the debate. But in philosophy, this is quite rare. Some philosophers might take the claim that a premise is ‘obvious’ or ‘clearly true’ as a challenge! But if a premise really is uncontroversial, you won’t need a defence of it. Sometimes, your paper will be almost entirely about one premise, to the point that your thesis might, in all honesty, be that premise itself. This should only happen where the other premises are generally accepted. All your work defending premise 1 is for naught if the reader disagrees with premise 2! Remember: a reader is only persuaded if they are convinced of the truth of every premise. If you find that your paper focuses almost entirely on one premise, despite other premises being controversial, that’s absolutely fine: but you need to alter your thesis. Make that premise your thesis, and explain the importance of it to the broader argument (which you now won’t be defending).

Sometimes, there are empirical claims amongst your premises. “Evil exists” might be one example. For simple existential claims like ‘there is evil in the world’ or ‘there is a black swan’, a single example usually suffices. But be careful of your definitions here. Unless you have a robust definition of ‘evil’, a reader might disagree that the example(s) you cite qualify! If your empirical claim is more complex or disputable – e.g. ‘Destruction of the cerebral cortex inhibits conscious experience’ – then your best option is usually to cite scientific or social scientific papers which demonstrate the phenomenon of interest. Your philosophy paper is about the philosophical implications of some fact(s) about the world, not about establishing those facts.

Otherwise, establishing the truth of a premise will require its own mini-argument! This is why philosophy papers which present a single argument for a single thesis may nonetheless contain multiple strands of argumentation. In the original version of the Problem of Evil argument, above, the argument might have looked like this:

1. God has the means and motive to prevent evil.
2. If God has the means and motive to prevent evil, then evil would not exist.
3. Evil exists.

Therefore, God does not exist.

This simpler version of the argumentative schema presented above has a couple of difficult premises. Premise 1 immediately stands out. How do we know that God can and wants to prevent evil? This is where my original version of the argument presented a mini-argument for that premise, drawing on the properties of God as all-powerful and all-loving to try to prove his capability and desire to prevent evil.

Of course, if you are now assembling a new argument to demonstrate the truth of one of your premises, you will need to show the truth of the premises of that new sub-argument too! Uh oh. If we need arguments for the premises in the argument for the premises of our argument (and so on!) where do we end? We’re tumbling down a philosophical rabbit hole.

We only have so much space to defend our argument, so at some point we are going to have to assume that the reader agrees with some claims. Hopefully these are relatively uncontroversial. But there is another way to avoid having to assume the reader’s agreement with a premise: conditionalising our thesis.

Defending a conditional thesis

A conditional thesis has the form ‘If … , then … ‘. We call the first part of the sentence (after ‘if’) the antecedent of the conditional, and the part after ‘then’ the consequent: “If antecedent, then consequent.” To form a conditional thesis, we take one of our premises and assume it. To do this, we make the premise our antecedent and the original thesis becomes the consequent.

For example, suppose I am worried that a reader might not agree with me that ‘God’ means a being which is all-powerful and all-loving. I don’t want to defend the claim ‘God is all-powerful and all-loving’ (perhaps I lack the space or haven’t got a good argument for that claim, or I’m aware there are other conceptions of God but don’t want to discuss them). Instead, I defend the following conditional thesis:

If God is defined as all-loving and all-powerful, then God does not exist.

My original thesis was that there is no God. But now, my thesis is a conditional: assuming ‘God’ would be an all-loving and all-powerful being, there is no God. In the example above, I had actually already embedded the assumption that God is all-powerful and all-loving into the conclusion. Sometimes, we can rewrite a conditional sentence in a simpler way. Previously, I wrote “There is no all-loving, all-powerful God”. This is equivalent to: “If God is defined as all-loving and all-powerful, then there is no God.”

Suppose instead that I was concerned that my reader would not agree that evil exists, or that I don’t want to have to defend that empirical claim in my paper. I could conditionalise my thesis again, and deliver the argument:

1. If God is all-powerful, then he could prevent evil.
2. If God is all-loving, then he would want to prevent evil.
3. If God has the means and the desire to prevent evil, then evil would not exist.

Therefore, if evil exists, then there is no all-powerful, all-loving God.

The more of my premises I bring into my thesis, the less I need to defend in my paper. But, my thesis has become narrower in scope. The claim “If evil exists, then there is no all-powerful, all-loving God” is less powerful than the claim “There is no God”. But as we said before, this would not usually be seen as a problem for a philosophy paper. We don’t expect to prove vast sweeping generalisations in a short paper. If you really did demonstrate that “If evil exists, then there is no all-powerful, all-loving God”, that would be a big enough deal!

There is another approach to integrating a undefended premise into your thesis. Because a conditional sentence can be rewritten as a disjunctive sentence (i.e. ‘Either … , or … ‘), you can include a premise by negating the premise and creating a disjunctive thesis.

For example, instead of “If evil exists, then there is no all-powerful, all-loving God”, I could have written: “Either evil does not exist, or there is no all-powerful, all-loving God”. This works out just the same (for reasons that will have to wait for our discussion of logical equivalences). If your reader might be reluctant to accept either alternative here, this could have the logical form of a dilemma. It is a matter of personal taste (and writing style) whether you choose to render your thesis as a conditional, a disjunction, or through some more elegant phrasing which serves the same purpose.

A persuasive argument for a precise thesis

A philosophy paper is an argument for a thesis. A good philosophy paper gives a persuasive argument for a precise, clearly stated thesis. Leaving aside the psychology of persuasion and assuming a level of rationality in our reader (which we should not do!), an argument is persuasive insofar as the reader is convinced that the conclusion follows from the premises, and that the premises are true. The job of a philosophy paper, then, is to convince the reader of exactly this. To convince them of this, they need to understand the premises and the conclusion, and the words involved. This is the business of defining terms, explaining the debate, recounting the arguments of others, and citing your sources. All of these elements are important because the reader cannot be convinced unless they understand. But the real work of a philosophy paper is in defending your premises and crafting an argument in which the conclusion really does follow from those premises. It’s that art to which we’ll now turn.

Latest edit: 01/03/2021 by CJ Blunt