# Philosophy

> Motion is a conversation, not a performance. The three pillars of interanimate — Respond, Continue, Respect.

## Motion is a conversation, not a performance [#motion-is-a-conversation-not-a-performance]

Most animation on the web is a *performance*: something decides in advance what will happen, presses play, and the person watches. A 300 ms slide. A 600 ms fade. The interface talks; the person waits.

interanimate starts from the opposite premise. **Interface motion is a conversation.** The person acts, the interface answers, the person acts again — often before the interface has finished answering. A good conversational partner responds immediately, never talks over you, can change course mid-sentence, and knows when to say nothing at all.

This framing comes from Apple's work on fluid interfaces, which describes animation as an ongoing exchange between a person and an object rather than something the interface prescribes. When an interface behaves this way, it stops feeling like a machine you operate and starts feeling like an extension of your own movement.

Everything in interanimate follows from taking that idea seriously and making it the default.

## The three pillars [#the-three-pillars]

The twelve [principles](/docs/principles) group under three pillars. If you remember nothing else, remember these.

### 1. Respond [#1-respond]

**The interface answers immediately — or not at all.**

Response is the foundation everything else sits on. Humans perceive a response within roughly a tenth of a second as caused by themselves; beyond that, they feel the machine. So acknowledgment happens on the press, not the release. Motion never sits between a person and the result they asked for. And when motion would only slow a frequent action down, the right response is no motion.

*Principles:* Respond first · Purpose or nothing · Frequency sets the budget · Fast is a feature

### 2. Continue [#2-continue]

**Nothing jumps, nothing restarts, nothing waits.**

Values on screen are continuous. When motion is interrupted, it continues from exactly where it is, at exactly the speed it was going. When a finger lets go, the finger's velocity carries into the animation without a seam. Objects come from somewhere and go somewhere, and the path tells you where. The user can grab anything that's moving, at any moment.

*Principles:* Never lock the user out · Continuity of value and velocity · Behavior over timelines · The hand is the source of truth · Every motion has an origin and a destination

### 3. Respect [#3-respect]

**Motion is for the person, on their terms.**

Motion spends a person's attention, time, and — for some people — physical comfort. It must earn that cost. Restraint is the default and expressiveness is earned. Motion is always optional; meaning never depends on it. And the experience has to hold up on a slow phone, a low battery, and a person mashing a button.

*Principles:* Restraint by default, expression earned · Motion is optional, meaning is not · Smooth under stress

## Three questions before anything moves [#three-questions-before-anything-moves]

Every motion in an interanimate interface should be able to answer three questions, in this order. The framework's defaults answer them for you; when you override a default, you're answering them yourself.

1. **Why does this move?** Name the purpose — feedback, orientation, state change, attention, or delight. If there is no purpose, nothing moves.
2. **How often will someone see it?** Frequency sets the budget. Things seen hundreds of times a day get no motion; rare moments may get more.
3. **What happens if they don't want it?** Every motion has a defined reduced-motion behavior before it ships.

## Design stance [#design-stance]

A few positions interanimate takes deliberately, so contributors and users know what to expect:

- **Opinionated defaults, unopinionated ceiling.** The intent layer is strongly opinionated. The layers underneath are not. Anyone can drop down a layer; nobody should *have* to.
- **Behavior over appearance.** The framework specifies how things move and respond, never how they look.
- **Physical, not literal.** Motion borrows the *feel* of the physical world — mass, momentum, resistance — because people already understand it. It does not simulate reality for its own sake.
- **The platform is a partner.** Where the web platform provides a capability natively (transitions, view transitions, scroll timelines, user preferences), interanimate's model maps onto it rather than competing with it.
- **Grounded in sources.** Every principle cites where it comes from. Where the framework departs from a source, it says so and says why.