It is possible to build a complex argument by answering just the first four of the five questions of argument:
What do you claim?
What are the reasons on which you base your claim?
What is the evidence on which you base your claim?
What warrants connect your reasoning to your claim?
But when an issue is contestable, you can seem arrogant or even ignorant if you fail to consider and to acknowledge the fifth question most readers are certain to ask:
How would you respond to someone who claimed something different?
What about their alternatives?
What about their objections?
What about their reservations?
Could you qualify your claim in any way?
It can be hard to answer questions like these, because we don’t like to admit that we might be, if not wrong, then at least not completely right. Our impulse is to be defensive, to counter-attack, fighting off our adversaries’ objections (Note the combative metaphors).
But when you can anticipate and then answer such questions, not just once, but throughout your argument, you can deepen and broaden its persuasive appeal by projecting a thoughtful and judicious attitude that can make friends and influence people.
When we say that there are two sides to every question, we understate the case by underestimating how complex most problems are. There are three, four, or even more sides to most issues and they differ not just over claims, but over warrants, over what counts as reasoning and evidence, and even over the existence of a problem at all. In conversation, those who offer endless alternatives and objections can sometimes seem deliberately obstructive – and they sometimes are. But in arguments about serious problems, you serve those around you poorly if, to avoid seeming obstructive, you offer only mindless agreement or silent dissent. All parties to an argument have a duty to air alternatives and raise objections in a spirit not of contention but of collaboration.
Most of us find it hard to engage with alternatives and objections for these reasons:
We are ignorant about them; we have overlooked them or we never sought them out at all.
We can’t imagine (even in principle) that there exist other views to consider.
We are afraid to acknowledge that we might be wrong or only partly right.
We fear we undercut our own claims when we acknowledge the existence of others.

Regardless of age, intelligence, education, even experience, we all have to resist the most common flaw in human thinking: We hold tightly to our own beliefs, seeking only what supports our prior claims, ignoring contradictory evidence, or distorting what we see until it fits our preconceptions. We don’t do this in purpose, but it’s something that we’re all inclined to do.
You can compensate for that flaw if you actively seek out views that contradict your own and study them until you understand why someone could believe them. If you are making an argument about an issue without well-known contradictory views, imagine a skeptical but helpful friend questioning two aspects of your argument:
Your friend might challenge the soundness of your argument; objecting that your claims, reaons, evidence, or warrants are incorrect or unjustified.
Your friend might acknowledge that your argument is sound, but offer alternatives – other claims, reasons, evidence, or warrants that complicate or qualify your argument.
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Either/Or thinking encourages us to reason in what are called disjunctive syllogisms:
You are either a conservative or a liberal.
You are not a conservative? Therefore, you must be a liberal.
You are not a liberal? Therefore, you must be a conservative.
The answer to the drug problem is either punishment or treatment.
You think treatment is the answer? You must be opposed to punishment.
You think punishment is the answer? You must be opposed to treatment.
In both examples, the reasoning is formally sound, but substantively false.
It offers what seem to be mutually exclusive choices, but are in fact not contradictory at all:
Maybe both choices are right; maybe we need tougher laws and better treatment.
Maybe we need slightly tougher laws and some new treatment programs.
Maybe both choices are wrong and a third one is right – smarter education.
Maybe all three are right – tougher laws, better treatment, smarter education.
Issues in the popular culture tend to be framed in either/or terms: TV shouting matches, bumper-sticker slogans, etc. But things are almost always more complex than either/or thinking allows. You owe readers a duty to avoid making problems more complex than they have to be, but also (as Einstein once said) no simpler than they really are.