Also known as logical syllogisms, these are a form of deduction
originally arranged by Aristotle. They come in a wide variety of
forms, but only a small number are logically valid.

The two most common are Modus Ponens and Hypothetical

Modus Ponens:                          Hypothetical Inference:

All systems are logical.             If I drink will become drunk.
A is a system                             I am drunk.
A must be logical.                     Therefore, I took a drink.

In both forms, the soundness of the conclusion (s) depends on the
soundness of all of the premises related with the conclusion.

Syllogisms may be called causal forms of inference (an article on
all it's forms
HERE), because the conclusions usually depend on
more than one premise, and there is no rule which says that
conclusions cannot contradict one another.

Since the system cannot be proven coherent, it must be assumed
that the conclusions are derived from the nature of the premises
exclusively, as numerous philosophers have emphasized in the
last 100 years.

For an example of coherent deduction, see
Categorical Deduction.
The difference may be criticized as a distinction between
empirical premises and systematic ones, and depending on the
types of logical biases, one or another may be deemed more or
trivial than the other.