If it is true that...

Christ was claimed to have been seen by many of his disciples, up to 500

and

Few to none of those alleged witnesses recanted their claim despite being faced with death

Then it must be true that...

The alleged witnesses were not lying

If it is true that...

The alleged witnesses were not lying

Then it must be true that...

The natural explanation of the alleged witnesses lying or conspiring about Jesus Christ's post-mortem appearances is false