Sorry, everyone ... I meant on their own, with no help from God
That was how I understood your OP which is why I posted what I did because I thought it needed further clarification in that salvation is impossible for man without the grace of God.
God supplies what is needed for man to see the truth and in seeing, what man really prefers, light or dark, is revealed.
God does not decide who believes or who doesn't believe but His promise is to save believers. It is by His determination alone that believers are saved and not by the act of our believing.
People seem to get confused by this. If you say "you have to believe in the Gospel" (which you do for salvation (Rm.1:16), they seem to think you are saying that it's one's own believing that saves them, forgetting it is only because this is what God has determined for believers in His great love and mercy.
John 3:16
For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.
The promise is to believers. There are only two types of people in the world, believers and unbelievers. The grace of God does not
cause us to be one or the other, His grace
reveals which one we are.