There are two parts of debate or critical thinking. First, you present an idea. Second, you make and evaluate arguments. After some arguing you can still do more presenting. You can’t start with arguing before any presenting, though.
When presenting, you say what an idea is. You explain what the idea says and why. You say how it works. You say what its goal is and how it achieves that goal. Or equivalently say what problem its trying to address and how it solves it. Or what its objective is and how it succeeds. You may also say the history of the idea, e.g. how it tries to improve on a previous flawed idea.
In the arguing part, you argue about an idea. You try to say why the idea is right or wrong, will or won’t work, is good or bad, etc. You have to know what the idea is before talking about it. Arguments are meta-ideas because they talk about prior ideas instead of standing on their own.
Critical Fallibilism (CF) says arguments should be negative (they should contradict an idea and say why it fails at a goal). Negative arguments are called criticism. Positive (supporting or justifying) arguments are OK only if they are equivalent to a negative argument. It’s impossible to positively prove that ideas work. CF also says arguments should be decisive (instead of arguing that something is mediocre, specify some goals it fails at).
Splitting debate into two parts is common. E.g. essay writers are often told to state a thesis and then give arguments for that thesis. Your thesis could be “X is false”, which allows arguing against someone else’s thesis.
You have to know what some ideas are before you can argue about them. There’s a simple logical need to present an idea before debating it.
People don’t always separate presenting an idea from arguing about it. Both are common parts of debates, and people often try to make some arguments while presenting their idea instead of waiting until after. This results in some confusion about the difference between presenting and arguing, and sometimes people call them both arguing.
It’s important to CF to separate presenting from arguing because CF says argument is negative but does not say presenting is negative. All argument is either criticism or implied criticism (the reason positive arguments seem to work is that they often imply a criticism and could be reworded as a criticism). But presenting an idea is not criticism.
Sometimes people see ideas being presented and think that shows that positive arguments are important. But presenting an idea itself is different than arguing about an idea. Presenting is non-meta and arguing is meta (meta means being about something else).
Part of why people mix up presentations of ideas with positive arguments is because presenting an idea has persuasive power. People often find the presentation itself pretty convincing without needing to hear any arguments. When people understand an idea, they may quickly persuade themselves of it. This can be viewed another way: when people dislike ideas, it’s often because they don’t understand those ideas. It can also be viewed as showing that people’s intuitions match CF’s claim that ideas start as non-refuted (the good status, rather than refuted) by default – just presenting an idea is often enough for people to like it as long as there are no criticisms to refute it.
When presenting an idea, we say why and how we think it will work. That might reasonably be referred to as saying why the idea is good. But saying why an idea is good could also mean giving positive arguments about the idea rather than sharing the idea itself.
The important thing to understand is that when CF says to use criticism not positive arguments, that doesn’t exclude presenting ideas. You still can and should share and explain ideas. It’s important to say what ideas are, how they work, and why they’re designed the way they are.
This is related to the Critical Rationalist view that ideas begin and stay unjustified, and can never gain additional positive status, but may become refuted by criticism. We learn by error correction, which uses negative arguments.
So we need (positive) presentations of ideas and (negative) arguments about ideas. CF’s advocacy of negative arguments only makes sense when presenting ideas is understood as separate from arguing about ideas.