In the 1950s, doctors appeared in cigarette advertisements. Not actors playing doctors — physicians, lending their authority to a product we now know kills people.

That's what certainty looks like from fifty years away.

Yesterday I wrote about how we judge the future by today's rules, and how the future ignores our rules and brings its own. I keep returning to the thought because of what it asks of us right now.

If some of what we're certain of today will look quaint in fifty years — and history says it will — what should we do with our certainty in the meantime?

Not abandon it. A conviction tested by decades of listening and engineering is worth holding firmly. Cables matter. Power quality matters. The room has the final say. I'll defend each of those all day, because the evidence of my own ears and our lab keeps confirming them.

But there's a difference between holding a conviction and sealing it shut. The audiophiles who insisted digital could never be musical sealed theirs shut — and missed twenty years of progress while the rest of us kept listening as DACs got better. The engineers who declared measurements had settled every question sealed theirs from the other direction. Both camps stopped asking.

How many wonderful surprises did each of them miss?

At PS Audio, we've built plenty of things we were sure about that later got humbled by something better — often our own next design. Good. That's the system working. Every product we've ever improved was an admission that yesterday's certainty had room in it.

So hold your convictions. Test them against everything you hear.

Just keep a hinge on the door.

Because somewhere out there is a piece of the puzzle none of us has heard yet — and the whole point of this hobby is that we get to keep listening for it.