Whatever begins to exist has a cause to its existence
The Kalam Cosmological Argument begins like this:
1. Whatever begins to exist has a cause to its existence.
2. The universe began to exist.
3. Therefore, the universe has a cause to its existence.
Today, I want to respond to two objections I hear frequently to the first premise.
Objection #1: The first premise equivocates on the phrase "begins to exist." In all of our experience, we only witness things coming into existence in the sense that matter or energy is restructured in some way. My car is made up of pre-existing material. The material that I am made of came out of star dust billions of years ago. When something comes into existence in this sense, our uniform experience tells us that there is always a cause. But when the Kalam argument uses the phrase "begins to exist" it isn't talking about the universe being made out of pre-existing material. It's talking about all the material of the universe coming into existence from nothing. Since we have no experience of anything coming into existence from nothing, we are not in a position to say whether it would require a cause or not.
Answer #1: My biggest problem with this objection is that it assumes our knowledge of causation is based on experience. I think that is a mistake. As David Hume pointed out, all we ever witness is contiguity in space and time. We don't actually witness causation. We assume causation when we witness contiguity in space and time. I think our knowledge of causation is a rational intuition. I know for a certainty that something cannot come into existence out of nothing without a cause, but my knowledge isn't based on anything I've experienced.
Objection #2: Some things do come into existence uncaused out of nothing. Pair production is an example. Electrons and positrons spontaneously pop in and out of existence. The universe could have, too.
Answer #2: When electron/positron pairs pop in and out of existence, they don't do so from and to absolute nothingness. Electron/positron pairs are produced from pre-existing material, namely gammas. And when they annihilate each other, they are converted back into gammas. So pair production and annihilation does not provide a counter-example to the principle that something cannot come into existence uncaused out of nothing.