You are confusing intelligence with consciousness (qualia). We simply don't know how qualia develops or how to measure it. We cannot discard, for example, than an ant has a greater qualia level than us. There are theories about qualia being connected to microtubules on neurons and quantum effects... the DOOM-playing neurons also have those microtubules. So you cannot say "definitely not".
Why do you quote only the end, the full sentence is: We cannot discard, for example, than an ant has a greater qualia level than
They're saying that since we don't know how to "measure consciousness" we can't be certain that an ant doesn't have more "consciousness" than us. Obviously it seems very unlikely, but we can't be certain
