A responsible researcher supports a claim with reasons based on evidence. But thoughtful readers don't accept a claim just because you back it up with your reasons and your evidence. Unless they think exactly as you do, they will probably think of evidence you haven't, interpret your evidence differently, or, from the same evidence, draw a different conclusion. They may reject the truth of your reasons, or accept them as true but deny that they are relevant to your claim and so cannot support it. They may think of alternative claims (and counterarguments) you did not consider. 

If you think that readers might question your argument in a certain way, you should acknowledge and respond to that question. This process of acknowledgment and response strengthens your argument by making it more realistic.

Example: TV violence can have harmful psychological effects on children (claim 1) because those exposed to large amounts of it tend to adopt the values of what they see (reason 1 supporting claim 1 / claim 2 supported by reason 2). Their constant exposure to violent images makes them unable to distinguish fantasy from reality (reason 2 supporting reason 1 / claim 2). Smith (1997) found that children ages 5-9 who watched more than three hours of violent television a day were 25 percent more likely to say that most of what they saw on television was "really happening" (evidence supporting reason 2). It is conceivable, of course, that children who tend to watch greater amounts of violent entertainment already have violent values (acknowledgment), but Jones (1989) found that children with no predisposition to violence were just as attracted to violent entertainment as those with a history of violence (response).