possibilist

Someone who advocates possibilism, the position that things do not need to actually exist in order to have properties.

A socialist who advocates focusing on small, achievable forms of immediate progress rather than an all-or-nothing commitment to revolution.

Someone who neither hopes without reason, nor fears without reason. Someone who uses analysis of data to understand the relative probability of future possibilities, instead of relying on intuition, emotions, personal experience, dogma, superstition, mainstream thought, or mental models (e.g., pessimism or optimism).