I also think logic is universal, Stu and Joe. Rhetoric isn't, but logic is. To give an example "Buy British to protect British jobs" is expressed as if it is logical, but it is one of the many invalid structures that Bill referred to. It might happen to be true, or it might protect some British jobs at the cost of losing more jobs in the import and transport sector, or it might be wholly false. What it definitely is is a statement intended to persuade you to behave in a certain way.   Almost all the arguments Joe will hear about the shelter will be like this.

Moving onto our aliens: Let's repeat the most famous syllogism:

All men are mortal
Socrates is a man
Therefore Socrates is mortal.

What does it need to enable the aliens have this? Five things, in my book. They need the concept of attribute (mortal, red, noisy, gloopy, ...) They need the concept of discrete group or set (men, whales, planets, stars, ...). They need the concept of individual things (Socrates, 'I', that specific tree ..). They need the concept that individuals have attributes. And they need to agree that the group can be considered to have an attribute if the members have that attribute.

I can imagine aliens with no concept of self, or at least no distinction between the self and the rest of the species. But one of the requirements of life is food, and so any intelligent life will at least distinguish between 'food' and 'not-food'. So I am convinced anything that has those concepts will have analogues of syllogisms, and also that these concepts are themselves universal.

Rhetoric, on the other hand, is a different matter. That depends on what seems 'good' to our aliens, which involves ethics, aesthetics and so much else, which there is no reason to think will be remotely similar to ours - after all, were rarely agree with each other about them ourselves!