Summary of "Alvin Plantinga - If God Knows the Future, What is Free Will?"

Focus

Alvin Plantinga evaluates common “defeaters” for theism — arguments or beliefs alleged to make belief in God irrational. He explains what counts as a defeater, surveys several prominent candidates (argument from evil, postmodern relativism, religious diversity), and argues that none of them automatically makes belief in God irrational so long as one’s belief was initially justified, rational, and warranted.

Key concepts and distinctions

Justified, rational, warranted belief Plantinga asks us to suppose a belief in God can be initially justified (not contrary to intellectual duty), rational (not a result of a mental malfunction), and have some degree of “warrant” — the difference between mere true belief (or a lucky guess) and knowledge.
Defeater (definition)

A defeater is a belief you acquire such that, given that new belief, you can no longer rationally hold the original belief. Example: believing someone was born in Los Angeles is defeasible if they tell you they were born in Seattle.
Epistemic distance Our cognitive perspective is far removed from God’s; just because we don’t know God’s reasons doesn’t mean there aren’t any.

Defeaters considered and Plantinga’s responses

Argument from evil (suffering and moral evil)

What it is:

The wide-ranging suffering and moral evil in the world makes belief in an all-powerful, all-good God seem unlikely.

Plantinga’s response:

God might have reasons for permitting evil (e.g., the Free Will Defense); we are unlikely to know those reasons because of epistemic distance.
The existence of evil can be a serious emotional or existential problem for the believer (anger, rebellion like Job), but that emotional or existential difficulty is not the same as an epistemic defeater that makes belief irrational.

Postmodernism / cultural relativism about truth

What it is:

The claim that truth is relative (e.g., “truth is what your peers will let you get away with saying”).

Plantinga’s response:

He rejects this account of truth: there is no good reason to think truth depends on what your cultural peers permit.
He highlights absurd or self-defeating consequences (for example, the idea that one could “not have done” a wrong act merely by getting peers to accept a lie).
Even if postmodernism casts doubt on some accepted standards, there is no reason to accept postmodernism itself as the final verdict on truth.

Religious diversity / disagreement

What it is:

Many religions and differing claim sets exist worldwide; this diversity is offered as a defeater for belief in a particular theistic claim (especially particular religions like Christianity).

Plantinga’s response:

The global prevalence of theism (broadly construed) means diversity doesn’t automatically defeat theism itself, though it may challenge particular religious formulations.
Disagreement with intelligent and morally upright people does not by itself show a position is irrational. After careful reflection, if you remain convinced, continuing to hold the belief is not automatically irrational.

Moral and philosophical disagreements more generally

Such disagreements are common; their mere existence does not amount to defeaters if one has reconsidered the evidence and still finds one’s belief justified.

Method for evaluating a putative defeater (implicit in Plantinga’s discussion)

Ask whether the original belief was initially justified, rational, and warranted.
Define the putative defeater precisely (a belief which, if true, would rationally undermine the original belief).
Ask whether the defeater provides reasons that are epistemically available and conclusive — for example, does it supply knowledge or evidence you would necessarily grasp?
Consider epistemic limitations (the epistemic distance to God); lack of understanding of God’s possible reasons is not sufficient to conclude there are none.
Reflect carefully and fairly on the defeater; if, after careful re-examination, your original belief still seems justified, the defeater hasn’t rendered your belief irrational.

Overall conclusion

The argument from evil, postmodern relativism, religious diversity, and ordinary moral and philosophical disagreement can pose serious challenges or emotional problems for believers and can undermine specific religious claims in some cases. But none of these automatically functions as a defeater that makes belief in God irrational, provided the believer’s belief was initially justified, rational, and warranted and survives careful reflection.

Speakers and sources featured

Alvin Plantinga — speaker and primary commentator.
References and cited items:
- The Book of Job (Job as an example of rebellion/anger toward God).
- The Free Will Defence / theodicy tradition.
- Postmodernism and cultural relativism.
- A newspaper anecdote (an unnamed man with a cement truck and the tragic death of his child) used illustratively.