Custom Post Type capabilities

I would really appreciate some help here. I have created custom post types and mapped capabilities. The custom post types show up in the admin panel, but I can’t add a new post. When I remove capabilities=> $capabilities and change it to capability_type => ‘post’ it starts working.

// Human Sciences posts

    $capabilities = array(
     'publish_posts'        => 'publish_human',
     'edit_posts'           => 'edit_humans',
     'edit_others_posts'    => 'edit_others_human',
     'delete_posts'         => 'delete_human',
     'delete_others_posts'  => 'delete_others_human',
     'read_private_posts'   => 'read_private_human',
     'edit_post'            => 'edit_human',
     'delete_post'          => 'delete_human',
     'read_post'            => 'read_human',

);

$labels = array(
    'name'                  => 'Human Sciences Post',
    'singular_name'         => 'Post',
    'menu_name'             => 'Human Sciences Posts',
    'name_admin_bar'        => 'Human Sciences',
    'add_new'               => 'Add New',
    'add_new_item'          => 'Add New Post',
    'new_item'              => 'New Human Sciences Post',
    'edit_item'             => 'Edit Post',
    'view_item'             => 'View Posts',
    'all_items'             => 'All Human Sciences Posts',
    'search_items'          => 'Search Human Sciences Posts',
    'parent_item_colon'     => 'Parent Posts',
    'not_found'             => 'No Post Found',
    'not_found_in_trash'    => 'No Post Found in Trash',

);

$args = array(
    'labels'                => $labels,
    'public'                => true, 
    'publicly_queryable'    => true,
    'show_ui'               => true,
    'show_in_menu'          => true,
    'menu_position'         => 6,
    'menu_icon'             => 'dashicons-visibility',
    'query_var'             => true,
    'rewrite'               => array( 'slug' => 'human-science' ),
    'capabilities'          => $capabilities,
    'has_archive'           => true,
    'hierarchical'          => true,
    'supports'              => array( 'title', 'editor', 'thumbnail', 'comments', 'post_formats' ),
    'taxonomies'            => array( 'category', 'post_tag')
);

I imagine that I have made a simple mistake, but I can’t figure it out. Could someone please have a look over the code and let me know what I have done wrong, please? I am pulling my hair out over here.