Boiling Water withてある and ている

Learners oftentimes question the difference between てある and ている. Let’s boil up some water and see what these auxiliaries really do.

てある

お湯が沸いてある has that distinct nuance of someone having intentionally set up this state – it implies human agency and purpose. It’s like “the water has been put into/left in a boiling state (for some purpose).”

This fits the general pattern where てある tends to focus on:

1. Resultant states of intentional actions
2. States maintained for a purpose
3. Someone’s deliberate arrangement

ている

沸いている can naturally describe water just boiling (either in process or resultant state), 沸いてある strongly suggests someone boiled it deliberately and left it that way for some purpose – like for tea or cooking.

This same contrast shows up in other pairs:

• 窓が開いている (window is open – could be natural or intentional)
• 窓が開いてある (window has been left open – someone opened it for a purpose)

Conclusion

The ている can be more “neutral” about agency, while てある nearly always implies human intervention and purpose. This likely relates to ある’s historical use in describing existence of situations/states rather than progressive actions.

Yes, there’s a conceptual link there – いる fundamentally expresses ongoing presence/existence, which maps nicely to both:

1. Animate beings actively existing (requires continuous “energy”/agency to maintain)
2. Ongoing processes/states (continuous aspect)

This might help explain why いる rather than ある was recruited for the ている construction. The inherent “active/ongoing” quality of いる makes it suitable for expressing:

• Progressive actions (沸いている – actively boiling)
• Maintained states (壊れている – continuing to be in broken state)
• Continuous existence (座っている – continuing to sit)

While ある, which has more of a static/resultative feel, is better suited for:

• Resultant states with purpose (開けてある – has been opened and left that way)
• Arranged situations (準備してある – has been prepared and exists in that state)