In my thesis I will be proposing situationalism: a new theory of how it is that things change over time. It is B-theoretic, eternalist and endurantist. The central contention of the theory is that what is true can differ in a metaphysically significant way from time to time. The theory emerges as a solution to the problem of change. In my first chapter, I argue that change is genuinely problematic (contra some of the recent literature). There are at least three ways to generate problems from change, and I elucidate problems from the law of non-contradiction and the indiscernibility of identicals. In the second chapter, I examine the nature of change and contend that the current major solutions to the problem fail to uphold our intuitive not...