You cannot count of the fact that true premises will lead to a true conclusion. The concepts of validity and invalidity will later help us determine fallacious arguments. One can reach a conclusion through a process of deduction or induction. Deduction is the process of deriving a conclusion that necessarily follows from a set of premises. In a deductive argument, if all the premises are true, the conclusion must be true.
All mammals are warm-blooded.
Therefore, all cats are warm-blooded. Induction is the process of drawing a conclusion, or supposing based on past observation, that a particular hypothesis is true. Therefore all birds probably have feathers. In science, the process of inductive inference is presented as the process from which one moves from a specific case, or cases, to a general hypothesis. So, each time we observe birds with feathers we help confirm the general hypothesis that all birds have feathers.