Tense Graph: A Tool for Visualizing the Logical Structure of Tense

TenseGraph is a web-based service that visualizes the structure of English tenses based on Gilles Fauconnier’s Mental Spaces theory. Rather than viewing tense as a simple timeline, this approach treats it as a process of creating and connecting different "spaces" in our minds. TenseGraph explains this process using the following four core elements:

Base Space
	The foundational starting point of the discourse. Usually representing the "present" where the speaker stands, it serves as the root for all temporal shifts.
Viewpoint Space
	The location where the "internal eye" or perspective is positioned. When speaking of the past, our viewpoint moves to a specific point in the past to observe the situation.
Event Space
	The specific point where an actual action or state occurs. The viewpoint and the event may coincide in the same space or exist in separate ones.
Focus Space
	The "active workspace" where new information is currently being added. It represents the specific space we are focusing on at the moment of communication.

In the subjunctive mood, the tense graph does not rely on the usual Viewpoint and Event space. Instead, it highlights two distinct conceptual spaces: Foundation and Expansion space.

Foundation space
	This represents the conditional base or premise. It is not anchored in actual time or events, but rather sets up a hypothetical situation — “if X were true.”
Expansion space
	From the Foundation, this space unfolds the possible consequences or developments. It shows what would happen if the condition were realized.

Irrealis structure

Thus, the irrealis sentence does not simply place events along a timeline. Instead, it structures meaning through a conditional base (Foundation) and the imagined outcomes (Expansion space), making visible how English uses hypothetical reasoning to extend beyond real-world temporal events. So, we represent the border of the node with a dotted line.

Arrows are used to indicate the flow of time:

	wavy arrows represent progression(continuous)
	dashed arrows represent completion(perfect)
	solid arrows indicate intervals and the direction of temporal flow rather than a specific point in time

By visualizing how these elements are arranged and linked, TenseGraph helps users understand the logical mechanics of language in a clear and structured way.