diff --git a/CHANGELOG.md b/CHANGELOG.md
index d2f8d6c..496648f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Queries requiring and excluding the same condition now return no matches instead of raising `AssertionError`.
 - Component reads and tag cleanup no longer retain unused entities through empty registry rows.
 - Failed component removals no longer create empty rows, and clearing removes existing empty rows.
 - Replacing component relations from an inherited view now preserves values which depend on the destination.
diff --git a/tcod/ecs/query.py b/tcod/ecs/query.py
index 5c42921..6b16fcb 100644
--- a/tcod/ecs/query.py
+++ b/tcod/ecs/query.py
@@ -237,10 +237,6 @@ class _QueryLogicalAnd:
     _all_of: frozenset[_Query] = frozenset()
     _none_of: frozenset[_Query] = frozenset()
 
-    def __attrs_post_init__(self) -> None:
-        """Verify the current state."""
-        assert self._all_of.isdisjoint(self._none_of)
-
     def _add_to_cache(self, registry: Registry, cache: _QueryCache) -> None:
         for dependency in itertools.chain(self._all_of, self._none_of):
             cache.dependencies[dependency].add((registry, self))
diff --git a/tests/test_ecs.py b/tests/test_ecs.py
index 4887fdd..006c2c2 100644
--- a/tests/test_ecs.py
+++ b/tests/test_ecs.py
@@ -7,7 +7,7 @@
 import pickletools
 import sys
 from collections.abc import Callable, Iterator  # noqa: TC003
-from typing import Final
+from typing import Any, Final
 
 import pytest
 
@@ -330,3 +330,29 @@ def test_type_form() -> None:
 
 def test_unpickle_is_a() -> None:
     assert pickle.loads(PICKLED_ISA) is tcod.ecs.IsA  # noqa: S301
+
+
+@pytest.mark.parametrize("kind", ["component", "tag", "relation"])
+@pytest.mark.parametrize("reverse", [False, True])
+def test_query_contradictory_filters(kind: str, *, reverse: bool) -> None:
+    """A conjunction excluding its own required condition has no matches."""
+    world = tcod.ecs.Registry()
+    actor = world["actor"]
+    conditions: dict[str, Any]
+    if kind == "component":
+        actor.components[int] = 3
+        conditions = {"components": [int]}
+    elif kind == "tag":
+        actor.tags.add("actor")
+        conditions = {"tags": ["actor"]}
+    else:
+        actor.relation_tag["room"] = world["room"]
+        conditions = {"relations": [("room", world["room"])]}
+    included = world.Q.all_of(**conditions)
+    excluded = world.Q.none_of(**conditions)
+    query = excluded.all_of(**conditions) if reverse else included.none_of(**conditions)
+    assert not query
+    assert not query.get_entities()
+    actor.clear()
+    assert not query
+    assert not included