Do the martyrs under the altar demonstrate that the dead are conscious?

The organization known as the "Iglesia Ni Cristo" claims that when the dead await judgment, they remain unconscious. However, some narratives in the Bible, such as the narrative of the martyrs under the altar, seem to contradict this teaching.

Revelation 6:9-11 (ESV) - 9 When he opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God and for the witness they had borne. 10 They cried out with a loud voice, "O Sovereign Lord, holy and true, how long before you will judge and avenge our blood on those who dwell on the earth?" 11 Then they were each given a white robe and told to rest a little longer, until the number of their fellow servants and their brothers should be complete, who were to be killed as they themselves had been.

Does this passage actually teach the dead are conscious? Indeed, it does.

These are actually martyrs and not a metaphor for something else.

While many of the things in the book of Revelation are symbolic, we have legitimate reasons to call them symbolic as opposed to actual or visions of the actual. We are told that martyrs cry out and are given no reason to think that a martyr is a metaphor for something that is not a martyr or that crying out is a metaphor for something that is not crying out. What would such things represent? The martyrs have been treated unjustly and they yearn for God's righteous judgment.

One objection raised is that an altar would not be large enough to fit that many martyrs under, but there are three errors being made here:
1. Under does not mean directly beneath, but at the foot of the altar, so the martyrs are not constrained by the space of the altar itself.
2. We have no way of knowing how large the altar is. How could we say it's not big enough?
3. A soul does not take up physical space. These martyrs are separated from their physical bodies. They do not consume physical space and if they did we would have no way of estimating how much space they consume.

It is silly to argue on the basis of the altar that this must be metaphor for something else.

Conclusion

The martyrs under the altar are conscious and yearn for justice. When we claim that the dead are unconscious, we call God a liar given what he has told us about the martyrs.

The martyrs will receive the justice they request. Let us make sure we are on the right side of God's justice by reading the scriptures and trusting in Christ alone for our salvation.