The goal of this paper is to analyze the dialectic nature of Aristotle's Metaphysics' Beta in the light of the content, process and utility of the dialectical method exposed by Aristotle in the Topics. After analyzing Beta book in the light of the Topics we can say that: a) on the nature of the assumptions used in Beta, although most of them are plausible opinions (endoxa), many of them are not, but empirical statements that Aristotle gives for good because these are true and self-evident. In addition, Beta aporiai are not formulated in terms of the four predicables; b) regarding the procedure of Beta, the development of aporiai adapts effectively to diaporetic method described in Top. I and dialectic dispute exposed in Top. VIII. However, Beta does not use polysemy, similarities and differences about terms included in the formulation of aporiai, neither uses topoi, argumentative schemes; c) Finally, as to the validity, the aim of Beta book is to reflect about the first principles of first philosophy and about the truth and falsity of plausible views concerning those first principles.