tend to devote more time to executing putative solutions. Deliberation and decision Deliberation is an important form of practical thinking. It aims at formulating possible courses of action and assessing their value by considering the reasons for and against them. This involves foresight to anticipate what might happen. Based on this foresight, different courses of action can be formulated in order to influence what will happen. Decisions are an important part of deliberation. They are about comparing alternative courses of action and choosing the most favorable one. Decision theory is a formal model of how ideal rational agents would make decisions. It is based on the idea that they should always choose the alternative with the highest expected value. Each alternative can lead to various possible outcomes, each of which has a different value. The expected value of an alternative consists in the sum of the values of each outcome associated with it multiplied by the probability that this outcome occurs. According to decision theory, a decision is rational if the agent chooses the alternative associated with the highest expected value, as assessed from the agent's own perspective. Various theorists emphasize the practical nature of thought, i.e. that thinking is usually guided by some kind of task it aims to solve. In this sense, thinking has been compared to trial-and-error seen in animal behavior when faced with a new problem. On this view, the important difference is that this process happens inwardly as a form of simulation. This process is often much more efficient since once the solution is found in thought, only the behavior corresponding to the found solution has to be outwardly carried out and not all the others. Episodic memory and imagination When thinking is understood in a wide sense, it includes both episodic memory and imagination. In episodic memory, events one experienced in the past are relived. It is a form of mental time travel in which the past experience is re-experienced. But this does not constitute an exact copy of the original experience since the episodic memory involves additional aspects and information not present in the original experience. This includes both a feeling of familiarity and chronological information about the past event in relation to the present. Memory aims at representing how things actually were in the past, in contrast to imagination, which presents objects without aiming to show how things actually are or were.