In this paper, conditions for existence of Gödel and Gödel-type solutions in Brans–Dicke (BD) scalar–tensor theory and their main features are studied. The consistency of equations of motion, causality violation and existence of CTCs (closed time-like curves) are investigated. The role which cosmological constant and Mach principle play to achieve the consistency of this model is studied
We verify the consistency of the Gödel-type solutions within the four-dimensional Chern-Simons modified gravity with the nondynamical Chern-Simons coefficient for different forms of matter including dust, fluid, scalar field, and electromagnetic field and discuss the related causality issues. We show that, unlike general relativity, a vacuum solution is possible in our theory. Another essentially new result of our theory having no analogue in general relativity consists in the existence of the hyperbolic causal solutions for a physically well-motivated matter.