Final answer:
The example provided represents deductive reasoning, where a general theory or premise is applied to arrive at a specific conclusion.
Step-by-step explanation:
The provided example, 'If all chocolate is fattening, and if this dessert has chocolate in it, then this dessert must be fattening,' represents deductive reasoning. Deductive reasoning involves starting with a general theory or premise and applying it to arrive at a specific conclusion. In this case, the general theory is that all chocolate is fattening, and the specific conclusion is that this dessert must be fattening because it contains chocolate.
Deductive reasoning can guarantee truth when the argument structure is valid and the premises are true, making it an essential method in scientific investigation and logical argumentation, as highlighted in the examples provided about scientists using hypotheses to reach conclusions about ducks and energy