diff --git a/runtime/src/main/java/org/capnproto/RpcState.java b/runtime/src/main/java/org/capnproto/RpcState.java
index 8310988..b9657ee 100644
--- a/runtime/src/main/java/org/capnproto/RpcState.java
+++ b/runtime/src/main/java/org/capnproto/RpcState.java
@@ -45,7 +45,7 @@ final class RpcState<VatId> {
 
         void dispose() {
             var ref = questions.find(this.id);
-            if (ref != null) {
+            if (ref == null) {
                 assert false: "Question ID no longer on table?";
                 return;
             }