The antinomies, from the Critique of Pure Reason, are contradictions which Immanuel Kant argued follow necessarily from our attempts to cognize the nature of transcendent reality by means of pure reason.
Kant thought that some certain antinomies of his (God and Freedom) could be resolved as "Postulates of Practical Reason".
Empirical reason cannot here play the role of establishing rational truths because it goes beyond possible experience and is applied to the sphere of that which transcends it.
They are connected with (1) the limitation of the universe in respect of space and time, (2) the theory that the whole consists of indivisible atoms (whereas, in fact, none such exist), (3) the problem of free will in relation to universal causality, and (4) the existence of a necessary being.
The second two are dubbed "dynamical" antinomies, presumably because the proponents of the thesis are not committing themselves solely to claims about spatio-temporal objects.